Commit | Line | Data |
96449e8e |
1 | package SQL::Abstract; # see doc at end of file |
2 | |
39999edd |
3 | use SQL::Abstract::_TempExtlib; |
4 | |
9d9d5bd6 |
5 | use Carp (); |
312d830b |
6 | use List::Util (); |
7 | use Scalar::Util (); |
a82e41dc |
8 | use Module::Runtime qw(use_module); |
3a9aca02 |
9 | use Moo; |
8b9b83ae |
10 | use namespace::clean; |
96449e8e |
11 | |
71c18fce |
12 | # DO NOT INCREMENT TO 2.0 WITHOUT COORDINATING WITH mst OR ribasushi |
13 | our $VERSION = '1.99_01'; |
14 | # DO NOT INCREMENT TO 2.0 WITHOUT COORDINATING WITH mst OR ribasushi |
7479e27e |
15 | |
22f1a437 |
16 | # This would confuse some packagers |
c520207b |
17 | $VERSION = eval $VERSION if $VERSION =~ /_/; # numify for warning-free dev releases |
96449e8e |
18 | |
19 | sub belch (@) { |
20 | my($func) = (caller(1))[3]; |
9d9d5bd6 |
21 | Carp::carp "[$func] Warning: ", @_; |
96449e8e |
22 | } |
23 | |
24 | sub puke (@) { |
25 | my($func) = (caller(1))[3]; |
9d9d5bd6 |
26 | Carp::croak "[$func] Fatal: ", @_; |
96449e8e |
27 | } |
28 | |
a82e41dc |
29 | has converter => (is => 'lazy', clearer => 'clear_converter'); |
96449e8e |
30 | |
3a9aca02 |
31 | has case => ( |
32 | is => 'ro', coerce => sub { $_[0] eq 'lower' ? 'lower' : undef } |
33 | ); |
96449e8e |
34 | |
3a9aca02 |
35 | has logic => ( |
36 | is => 'ro', coerce => sub { uc($_[0]) }, default => sub { 'OR' } |
37 | ); |
96449e8e |
38 | |
3a9aca02 |
39 | has bindtype => ( |
40 | is => 'ro', default => sub { 'normal' } |
41 | ); |
96449e8e |
42 | |
3a9aca02 |
43 | has cmp => (is => 'ro', default => sub { '=' }); |
96449e8e |
44 | |
3a9aca02 |
45 | has sqltrue => (is => 'ro', default => sub { '1=1' }); |
46 | has sqlfalse => (is => 'ro', default => sub { '0=1' }); |
47 | |
48 | has special_ops => (is => 'ro', default => sub { [] }); |
49 | has unary_ops => (is => 'ro', default => sub { [] }); |
59f23b3d |
50 | |
a82e41dc |
51 | # FIXME |
52 | # need to guard against ()'s in column names too, but this will break tons of |
53 | # hacks... ideas anyone? |
8f57728a |
54 | |
3a9aca02 |
55 | has injection_guard => ( |
56 | is => 'ro', |
57 | default => sub { |
58 | qr/ |
59 | \; |
60 | | |
61 | ^ \s* go \s |
62 | /xmi; |
63 | } |
64 | ); |
65 | |
29a3e5dc |
66 | has renderer => (is => 'lazy', clearer => 'clear_renderer'); |
3a9aca02 |
67 | |
29a3e5dc |
68 | has name_sep => ( |
69 | is => 'rw', default => sub { '.' }, |
a82e41dc |
70 | trigger => sub { |
71 | $_[0]->clear_renderer; |
72 | $_[0]->clear_converter; |
73 | }, |
29a3e5dc |
74 | ); |
3a9aca02 |
75 | |
29a3e5dc |
76 | has quote_char => ( |
77 | is => 'rw', |
a82e41dc |
78 | trigger => sub { |
79 | $_[0]->clear_renderer; |
80 | $_[0]->clear_converter; |
81 | }, |
29a3e5dc |
82 | ); |
a9bb5c4c |
83 | |
62d17764 |
84 | has collapse_aliases => ( |
85 | is => 'ro', |
86 | default => sub { 0 } |
87 | ); |
88 | |
a82e41dc |
89 | has always_quote => ( |
90 | is => 'rw', default => sub { 1 }, |
91 | trigger => sub { |
92 | $_[0]->clear_renderer; |
93 | $_[0]->clear_converter; |
94 | }, |
95 | ); |
3a9aca02 |
96 | |
97 | has convert => (is => 'ro'); |
98 | |
99 | has array_datatypes => (is => 'ro'); |
100 | |
a82e41dc |
101 | has converter_class => ( |
dfaa9684 |
102 | is => 'rw', lazy => 1, builder => '_build_converter_class', |
103 | trigger => sub { shift->clear_converter }, |
a82e41dc |
104 | ); |
105 | |
dfaa9684 |
106 | sub _build_converter_class { |
107 | use_module('SQL::Abstract::Converter') |
108 | } |
109 | |
a82e41dc |
110 | has renderer_class => ( |
1fa55ded |
111 | is => 'rw', lazy => 1, clearer => 1, builder => 1, |
dfaa9684 |
112 | trigger => sub { shift->clear_renderer }, |
a82e41dc |
113 | ); |
114 | |
1fa55ded |
115 | after clear_renderer_class => sub { shift->clear_renderer }; |
116 | |
dfaa9684 |
117 | sub _build_renderer_class { |
a60d973a |
118 | my ($self) = @_; |
119 | my ($class, @roles) = ( |
120 | $self->_build_base_renderer_class, $self->_build_renderer_roles |
121 | ); |
122 | return $class unless @roles; |
123 | return use_module('Moo::Role')->create_class_with_roles($class, @roles); |
124 | } |
125 | |
126 | sub _build_base_renderer_class { |
dfaa9684 |
127 | use_module('Data::Query::Renderer::SQL::Naive') |
128 | } |
129 | |
a60d973a |
130 | sub _build_renderer_roles { () } |
131 | |
a82e41dc |
132 | sub _converter_args { |
133 | my ($self) = @_; |
134 | Scalar::Util::weaken($self); |
135 | +{ |
136 | lower_case => $self->case, |
137 | default_logic => $self->logic, |
138 | bind_meta => not($self->bindtype eq 'normal'), |
139 | identifier_sep => $self->name_sep, |
140 | (map +($_ => $self->$_), qw( |
141 | cmp sqltrue sqlfalse injection_guard convert array_datatypes |
142 | )), |
143 | special_ops => [ |
144 | map { |
145 | my $sub = $_->{handler}; |
146 | +{ |
147 | %$_, |
148 | handler => sub { $self->$sub(@_) } |
149 | } |
150 | } @{$self->special_ops} |
151 | ], |
152 | renderer_will_quote => ( |
153 | defined($self->quote_char) and $self->always_quote |
154 | ), |
155 | } |
156 | } |
157 | |
158 | sub _build_converter { |
159 | my ($self) = @_; |
dfaa9684 |
160 | $self->converter_class->new($self->_converter_args); |
a82e41dc |
161 | } |
162 | |
163 | sub _renderer_args { |
3a9aca02 |
164 | my ($self) = @_; |
3a9aca02 |
165 | my ($chars); |
166 | for ($self->quote_char) { |
167 | $chars = defined() ? (ref() ? $_ : [$_]) : ['','']; |
168 | } |
a82e41dc |
169 | +{ |
3a9aca02 |
170 | quote_chars => $chars, always_quote => $self->always_quote, |
171 | identifier_sep => $self->name_sep, |
62d17764 |
172 | collapse_aliases => $self->collapse_aliases, |
3a9aca02 |
173 | ($self->case ? (lc_keywords => 1) : ()), # always 'lower' if it exists |
a82e41dc |
174 | }; |
175 | } |
176 | |
177 | sub _build_renderer { |
178 | my ($self) = @_; |
dfaa9684 |
179 | $self->renderer_class->new($self->_renderer_args); |
b6251592 |
180 | } |
96449e8e |
181 | |
8f57728a |
182 | sub _render_dq { |
183 | my ($self, $dq) = @_; |
9057306b |
184 | if (!$dq) { |
185 | return ''; |
186 | } |
3a9aca02 |
187 | my ($sql, @bind) = @{$self->renderer->render($dq)}; |
b4951847 |
188 | wantarray ? |
189 | ($self->{bindtype} eq 'normal' |
190 | ? ($sql, map $_->{value}, @bind) |
a420b11f |
191 | : ($sql, map [ $_->{value_meta}, $_->{value} ], @bind) |
b4951847 |
192 | ) |
193 | : $sql; |
194 | } |
195 | |
a9bb5c4c |
196 | sub _render_sqla { |
197 | my ($self, $type, @args) = @_; |
a82e41dc |
198 | $self->_render_dq($self->converter->${\"_${type}_to_dq"}(@args)); |
170e6c33 |
199 | } |
200 | |
a9bb5c4c |
201 | sub insert { shift->_render_sqla(insert => @_) } |
fe3ae272 |
202 | |
a9bb5c4c |
203 | sub update { shift->_render_sqla(update => @_) } |
9057306b |
204 | |
a9bb5c4c |
205 | sub select { shift->_render_sqla(select => @_) } |
9057306b |
206 | |
a9bb5c4c |
207 | sub delete { shift->_render_sqla(delete => @_) } |
96449e8e |
208 | |
96449e8e |
209 | sub where { |
210 | my ($self, $where, $order) = @_; |
211 | |
1d6b8d4d |
212 | my $sql = ''; |
213 | my @bind; |
214 | |
96449e8e |
215 | # where ? |
1d6b8d4d |
216 | ($sql, @bind) = $self->_recurse_where($where) if defined($where); |
96449e8e |
217 | $sql = $sql ? $self->_sqlcase(' where ') . "( $sql )" : ''; |
218 | |
219 | # order by? |
220 | if ($order) { |
221 | $sql .= $self->_order_by($order); |
222 | } |
223 | |
9d48860e |
224 | return wantarray ? ($sql, @bind) : $sql; |
96449e8e |
225 | } |
226 | |
a9bb5c4c |
227 | sub _recurse_where { shift->_render_sqla(where => @_) } |
d4e889af |
228 | |
96449e8e |
229 | sub _order_by { |
230 | my ($self, $arg) = @_; |
a82e41dc |
231 | if (my $dq = $self->converter->_order_by_to_dq($arg)) { |
b4951847 |
232 | # SQLA generates ' ORDER BY foo'. The hilarity. |
233 | wantarray |
234 | ? do { my @r = $self->_render_dq($dq); $r[0] = ' '.$r[0]; @r } |
235 | : ' '.$self->_render_dq($dq); |
236 | } else { |
237 | ''; |
f267b646 |
238 | } |
f267b646 |
239 | } |
240 | |
955e77ca |
241 | # highly optimized, as it's called way too often |
96449e8e |
242 | sub _quote { |
955e77ca |
243 | # my ($self, $label) = @_; |
96449e8e |
244 | |
955e77ca |
245 | return '' unless defined $_[1]; |
955e77ca |
246 | return ${$_[1]} if ref($_[1]) eq 'SCALAR'; |
96449e8e |
247 | |
b6251592 |
248 | unless ($_[0]->{quote_char}) { |
170e6c33 |
249 | $_[0]->_assert_pass_injection_guard($_[1]); |
b6251592 |
250 | return $_[1]; |
251 | } |
96449e8e |
252 | |
07d7c35c |
253 | my $qref = ref $_[0]->{quote_char}; |
955e77ca |
254 | my ($l, $r); |
07d7c35c |
255 | if (!$qref) { |
256 | ($l, $r) = ( $_[0]->{quote_char}, $_[0]->{quote_char} ); |
955e77ca |
257 | } |
07d7c35c |
258 | elsif ($qref eq 'ARRAY') { |
259 | ($l, $r) = @{$_[0]->{quote_char}}; |
955e77ca |
260 | } |
261 | else { |
262 | puke "Unsupported quote_char format: $_[0]->{quote_char}"; |
263 | } |
96449e8e |
264 | |
07d7c35c |
265 | # parts containing * are naturally unquoted |
266 | return join( $_[0]->{name_sep}||'', map |
955e77ca |
267 | { $_ eq '*' ? $_ : $l . $_ . $r } |
268 | ( $_[0]->{name_sep} ? split (/\Q$_[0]->{name_sep}\E/, $_[1] ) : $_[1] ) |
269 | ); |
96449e8e |
270 | } |
271 | |
a82e41dc |
272 | sub _assert_pass_injection_guard { |
273 | if ($_[1] =~ $_[0]->{injection_guard}) { |
274 | my $class = ref $_[0]; |
f2a0d52b |
275 | die "Possible SQL injection attempt '$_[1]'. If this is indeed a part of " |
276 | . "the desired SQL use literal SQL ( \'...' or \[ '...' ] ) or supply " |
277 | . "your own {injection_guard} attribute to ${class}->new()" |
a82e41dc |
278 | } |
279 | } |
96449e8e |
280 | |
281 | # Conversion, if applicable |
282 | sub _convert ($) { |
07d7c35c |
283 | #my ($self, $arg) = @_; |
07d7c35c |
284 | if ($_[0]->{convert}) { |
285 | return $_[0]->_sqlcase($_[0]->{convert}) .'(' . $_[1] . ')'; |
96449e8e |
286 | } |
07d7c35c |
287 | return $_[1]; |
96449e8e |
288 | } |
289 | |
290 | # And bindtype |
291 | sub _bindtype (@) { |
07d7c35c |
292 | #my ($self, $col, @vals) = @_; |
07d7c35c |
293 | # called often - tighten code |
294 | return $_[0]->{bindtype} eq 'columns' |
295 | ? map {[$_[1], $_]} @_[2 .. $#_] |
296 | : @_[2 .. $#_] |
297 | ; |
96449e8e |
298 | } |
299 | |
fe3ae272 |
300 | # Dies if any element of @bind is not in [colname => value] format |
301 | # if bindtype is 'columns'. |
302 | sub _assert_bindval_matches_bindtype { |
c94a6c93 |
303 | # my ($self, @bind) = @_; |
304 | my $self = shift; |
fe3ae272 |
305 | if ($self->{bindtype} eq 'columns') { |
c94a6c93 |
306 | for (@_) { |
307 | if (!defined $_ || ref($_) ne 'ARRAY' || @$_ != 2) { |
3a06278c |
308 | puke "bindtype 'columns' selected, you need to pass: [column_name => bind_value]" |
fe3ae272 |
309 | } |
310 | } |
311 | } |
312 | } |
313 | |
96449e8e |
314 | # Fix SQL case, if so requested |
315 | sub _sqlcase { |
96449e8e |
316 | # LDNOTE: if $self->{case} is true, then it contains 'lower', so we |
317 | # don't touch the argument ... crooked logic, but let's not change it! |
07d7c35c |
318 | return $_[0]->{case} ? $_[1] : uc($_[1]); |
96449e8e |
319 | } |
320 | |
96449e8e |
321 | sub values { |
322 | my $self = shift; |
323 | my $data = shift || return; |
324 | puke "Argument to ", __PACKAGE__, "->values must be a \\%hash" |
325 | unless ref $data eq 'HASH'; |
bab725ce |
326 | |
327 | my @all_bind; |
328 | foreach my $k ( sort keys %$data ) { |
329 | my $v = $data->{$k}; |
5cf3969e |
330 | local our $Cur_Col_Meta = $k; |
a9bb5c4c |
331 | my ($sql, @bind) = $self->_render_sqla( |
332 | mutation_rhs => $v |
5cf3969e |
333 | ); |
334 | push @all_bind, @bind; |
bab725ce |
335 | } |
336 | |
337 | return @all_bind; |
96449e8e |
338 | } |
339 | |
340 | sub generate { |
341 | my $self = shift; |
342 | |
343 | my(@sql, @sqlq, @sqlv); |
344 | |
345 | for (@_) { |
346 | my $ref = ref $_; |
347 | if ($ref eq 'HASH') { |
348 | for my $k (sort keys %$_) { |
349 | my $v = $_->{$k}; |
350 | my $r = ref $v; |
351 | my $label = $self->_quote($k); |
352 | if ($r eq 'ARRAY') { |
fe3ae272 |
353 | # literal SQL with bind |
354 | my ($sql, @bind) = @$v; |
355 | $self->_assert_bindval_matches_bindtype(@bind); |
96449e8e |
356 | push @sqlq, "$label = $sql"; |
fe3ae272 |
357 | push @sqlv, @bind; |
96449e8e |
358 | } elsif ($r eq 'SCALAR') { |
fe3ae272 |
359 | # literal SQL without bind |
96449e8e |
360 | push @sqlq, "$label = $$v"; |
9d48860e |
361 | } else { |
96449e8e |
362 | push @sqlq, "$label = ?"; |
363 | push @sqlv, $self->_bindtype($k, $v); |
364 | } |
365 | } |
366 | push @sql, $self->_sqlcase('set'), join ', ', @sqlq; |
367 | } elsif ($ref eq 'ARRAY') { |
368 | # unlike insert(), assume these are ONLY the column names, i.e. for SQL |
369 | for my $v (@$_) { |
370 | my $r = ref $v; |
fe3ae272 |
371 | if ($r eq 'ARRAY') { # literal SQL with bind |
372 | my ($sql, @bind) = @$v; |
373 | $self->_assert_bindval_matches_bindtype(@bind); |
374 | push @sqlq, $sql; |
375 | push @sqlv, @bind; |
376 | } elsif ($r eq 'SCALAR') { # literal SQL without bind |
96449e8e |
377 | # embedded literal SQL |
378 | push @sqlq, $$v; |
9d48860e |
379 | } else { |
96449e8e |
380 | push @sqlq, '?'; |
381 | push @sqlv, $v; |
382 | } |
383 | } |
384 | push @sql, '(' . join(', ', @sqlq) . ')'; |
385 | } elsif ($ref eq 'SCALAR') { |
386 | # literal SQL |
387 | push @sql, $$_; |
388 | } else { |
389 | # strings get case twiddled |
390 | push @sql, $self->_sqlcase($_); |
391 | } |
392 | } |
393 | |
394 | my $sql = join ' ', @sql; |
395 | |
396 | # this is pretty tricky |
397 | # if ask for an array, return ($stmt, @bind) |
398 | # otherwise, s/?/shift @sqlv/ to put it inline |
399 | if (wantarray) { |
400 | return ($sql, @sqlv); |
401 | } else { |
402 | 1 while $sql =~ s/\?/my $d = shift(@sqlv); |
403 | ref $d ? $d->[1] : $d/e; |
404 | return $sql; |
405 | } |
406 | } |
407 | |
96449e8e |
408 | 1; |
409 | |
410 | |
96449e8e |
411 | __END__ |
32eab2da |
412 | |
413 | =head1 NAME |
414 | |
415 | SQL::Abstract - Generate SQL from Perl data structures |
416 | |
417 | =head1 SYNOPSIS |
418 | |
419 | use SQL::Abstract; |
420 | |
421 | my $sql = SQL::Abstract->new; |
422 | |
521647e7 |
423 | my($stmt, @bind) = $sql->select($source, \@fields, \%where, \@order); |
32eab2da |
424 | |
425 | my($stmt, @bind) = $sql->insert($table, \%fieldvals || \@values); |
426 | |
427 | my($stmt, @bind) = $sql->update($table, \%fieldvals, \%where); |
428 | |
429 | my($stmt, @bind) = $sql->delete($table, \%where); |
430 | |
431 | # Then, use these in your DBI statements |
432 | my $sth = $dbh->prepare($stmt); |
433 | $sth->execute(@bind); |
434 | |
435 | # Just generate the WHERE clause |
abe72f94 |
436 | my($stmt, @bind) = $sql->where(\%where, \@order); |
32eab2da |
437 | |
438 | # Return values in the same order, for hashed queries |
439 | # See PERFORMANCE section for more details |
440 | my @bind = $sql->values(\%fieldvals); |
441 | |
442 | =head1 DESCRIPTION |
443 | |
444 | This module was inspired by the excellent L<DBIx::Abstract>. |
445 | However, in using that module I found that what I really wanted |
446 | to do was generate SQL, but still retain complete control over my |
447 | statement handles and use the DBI interface. So, I set out to |
448 | create an abstract SQL generation module. |
449 | |
450 | While based on the concepts used by L<DBIx::Abstract>, there are |
451 | several important differences, especially when it comes to WHERE |
452 | clauses. I have modified the concepts used to make the SQL easier |
453 | to generate from Perl data structures and, IMO, more intuitive. |
454 | The underlying idea is for this module to do what you mean, based |
455 | on the data structures you provide it. The big advantage is that |
456 | you don't have to modify your code every time your data changes, |
457 | as this module figures it out. |
458 | |
459 | To begin with, an SQL INSERT is as easy as just specifying a hash |
460 | of C<key=value> pairs: |
461 | |
462 | my %data = ( |
463 | name => 'Jimbo Bobson', |
464 | phone => '123-456-7890', |
465 | address => '42 Sister Lane', |
466 | city => 'St. Louis', |
467 | state => 'Louisiana', |
468 | ); |
469 | |
470 | The SQL can then be generated with this: |
471 | |
472 | my($stmt, @bind) = $sql->insert('people', \%data); |
473 | |
474 | Which would give you something like this: |
475 | |
476 | $stmt = "INSERT INTO people |
477 | (address, city, name, phone, state) |
478 | VALUES (?, ?, ?, ?, ?)"; |
479 | @bind = ('42 Sister Lane', 'St. Louis', 'Jimbo Bobson', |
480 | '123-456-7890', 'Louisiana'); |
481 | |
482 | These are then used directly in your DBI code: |
483 | |
484 | my $sth = $dbh->prepare($stmt); |
485 | $sth->execute(@bind); |
486 | |
96449e8e |
487 | =head2 Inserting and Updating Arrays |
488 | |
489 | If your database has array types (like for example Postgres), |
490 | activate the special option C<< array_datatypes => 1 >> |
9d48860e |
491 | when creating the C<SQL::Abstract> object. |
96449e8e |
492 | Then you may use an arrayref to insert and update database array types: |
493 | |
494 | my $sql = SQL::Abstract->new(array_datatypes => 1); |
495 | my %data = ( |
496 | planets => [qw/Mercury Venus Earth Mars/] |
497 | ); |
9d48860e |
498 | |
96449e8e |
499 | my($stmt, @bind) = $sql->insert('solar_system', \%data); |
500 | |
501 | This results in: |
502 | |
503 | $stmt = "INSERT INTO solar_system (planets) VALUES (?)" |
504 | |
505 | @bind = (['Mercury', 'Venus', 'Earth', 'Mars']); |
506 | |
507 | |
508 | =head2 Inserting and Updating SQL |
509 | |
510 | In order to apply SQL functions to elements of your C<%data> you may |
511 | specify a reference to an arrayref for the given hash value. For example, |
512 | if you need to execute the Oracle C<to_date> function on a value, you can |
513 | say something like this: |
32eab2da |
514 | |
515 | my %data = ( |
516 | name => 'Bill', |
96449e8e |
517 | date_entered => \["to_date(?,'MM/DD/YYYY')", "03/02/2003"], |
9d48860e |
518 | ); |
32eab2da |
519 | |
520 | The first value in the array is the actual SQL. Any other values are |
521 | optional and would be included in the bind values array. This gives |
522 | you: |
523 | |
524 | my($stmt, @bind) = $sql->insert('people', \%data); |
525 | |
9d48860e |
526 | $stmt = "INSERT INTO people (name, date_entered) |
32eab2da |
527 | VALUES (?, to_date(?,'MM/DD/YYYY'))"; |
528 | @bind = ('Bill', '03/02/2003'); |
529 | |
530 | An UPDATE is just as easy, all you change is the name of the function: |
531 | |
532 | my($stmt, @bind) = $sql->update('people', \%data); |
533 | |
534 | Notice that your C<%data> isn't touched; the module will generate |
535 | the appropriately quirky SQL for you automatically. Usually you'll |
536 | want to specify a WHERE clause for your UPDATE, though, which is |
537 | where handling C<%where> hashes comes in handy... |
538 | |
96449e8e |
539 | =head2 Complex where statements |
540 | |
32eab2da |
541 | This module can generate pretty complicated WHERE statements |
542 | easily. For example, simple C<key=value> pairs are taken to mean |
543 | equality, and if you want to see if a field is within a set |
544 | of values, you can use an arrayref. Let's say we wanted to |
545 | SELECT some data based on this criteria: |
546 | |
547 | my %where = ( |
548 | requestor => 'inna', |
549 | worker => ['nwiger', 'rcwe', 'sfz'], |
550 | status => { '!=', 'completed' } |
551 | ); |
552 | |
553 | my($stmt, @bind) = $sql->select('tickets', '*', \%where); |
554 | |
555 | The above would give you something like this: |
556 | |
557 | $stmt = "SELECT * FROM tickets WHERE |
558 | ( requestor = ? ) AND ( status != ? ) |
559 | AND ( worker = ? OR worker = ? OR worker = ? )"; |
560 | @bind = ('inna', 'completed', 'nwiger', 'rcwe', 'sfz'); |
561 | |
562 | Which you could then use in DBI code like so: |
563 | |
564 | my $sth = $dbh->prepare($stmt); |
565 | $sth->execute(@bind); |
566 | |
567 | Easy, eh? |
568 | |
569 | =head1 FUNCTIONS |
570 | |
571 | The functions are simple. There's one for each major SQL operation, |
572 | and a constructor you use first. The arguments are specified in a |
9d48860e |
573 | similar order to each function (table, then fields, then a where |
32eab2da |
574 | clause) to try and simplify things. |
575 | |
83cab70b |
576 | |
83cab70b |
577 | |
32eab2da |
578 | |
579 | =head2 new(option => 'value') |
580 | |
581 | The C<new()> function takes a list of options and values, and returns |
582 | a new B<SQL::Abstract> object which can then be used to generate SQL |
583 | through the methods below. The options accepted are: |
584 | |
585 | =over |
586 | |
587 | =item case |
588 | |
589 | If set to 'lower', then SQL will be generated in all lowercase. By |
590 | default SQL is generated in "textbook" case meaning something like: |
591 | |
592 | SELECT a_field FROM a_table WHERE some_field LIKE '%someval%' |
593 | |
96449e8e |
594 | Any setting other than 'lower' is ignored. |
595 | |
32eab2da |
596 | =item cmp |
597 | |
598 | This determines what the default comparison operator is. By default |
599 | it is C<=>, meaning that a hash like this: |
600 | |
601 | %where = (name => 'nwiger', email => 'nate@wiger.org'); |
602 | |
603 | Will generate SQL like this: |
604 | |
605 | WHERE name = 'nwiger' AND email = 'nate@wiger.org' |
606 | |
607 | However, you may want loose comparisons by default, so if you set |
608 | C<cmp> to C<like> you would get SQL such as: |
609 | |
610 | WHERE name like 'nwiger' AND email like 'nate@wiger.org' |
611 | |
3af02ccb |
612 | You can also override the comparison on an individual basis - see |
32eab2da |
613 | the huge section on L</"WHERE CLAUSES"> at the bottom. |
614 | |
96449e8e |
615 | =item sqltrue, sqlfalse |
616 | |
617 | Expressions for inserting boolean values within SQL statements. |
6e0c6552 |
618 | By default these are C<1=1> and C<1=0>. They are used |
619 | by the special operators C<-in> and C<-not_in> for generating |
620 | correct SQL even when the argument is an empty array (see below). |
96449e8e |
621 | |
32eab2da |
622 | =item logic |
623 | |
624 | This determines the default logical operator for multiple WHERE |
7cac25e6 |
625 | statements in arrays or hashes. If absent, the default logic is "or" |
626 | for arrays, and "and" for hashes. This means that a WHERE |
32eab2da |
627 | array of the form: |
628 | |
629 | @where = ( |
9d48860e |
630 | event_date => {'>=', '2/13/99'}, |
631 | event_date => {'<=', '4/24/03'}, |
32eab2da |
632 | ); |
633 | |
7cac25e6 |
634 | will generate SQL like this: |
32eab2da |
635 | |
636 | WHERE event_date >= '2/13/99' OR event_date <= '4/24/03' |
637 | |
638 | This is probably not what you want given this query, though (look |
639 | at the dates). To change the "OR" to an "AND", simply specify: |
640 | |
641 | my $sql = SQL::Abstract->new(logic => 'and'); |
642 | |
643 | Which will change the above C<WHERE> to: |
644 | |
645 | WHERE event_date >= '2/13/99' AND event_date <= '4/24/03' |
646 | |
96449e8e |
647 | The logic can also be changed locally by inserting |
7cac25e6 |
648 | a modifier in front of an arrayref : |
96449e8e |
649 | |
9d48860e |
650 | @where = (-and => [event_date => {'>=', '2/13/99'}, |
7cac25e6 |
651 | event_date => {'<=', '4/24/03'} ]); |
96449e8e |
652 | |
653 | See the L</"WHERE CLAUSES"> section for explanations. |
654 | |
32eab2da |
655 | =item convert |
656 | |
657 | This will automatically convert comparisons using the specified SQL |
658 | function for both column and value. This is mostly used with an argument |
659 | of C<upper> or C<lower>, so that the SQL will have the effect of |
660 | case-insensitive "searches". For example, this: |
661 | |
662 | $sql = SQL::Abstract->new(convert => 'upper'); |
663 | %where = (keywords => 'MaKe iT CAse inSeNSItive'); |
664 | |
665 | Will turn out the following SQL: |
666 | |
667 | WHERE upper(keywords) like upper('MaKe iT CAse inSeNSItive') |
668 | |
669 | The conversion can be C<upper()>, C<lower()>, or any other SQL function |
670 | that can be applied symmetrically to fields (actually B<SQL::Abstract> does |
671 | not validate this option; it will just pass through what you specify verbatim). |
672 | |
673 | =item bindtype |
674 | |
675 | This is a kludge because many databases suck. For example, you can't |
676 | just bind values using DBI's C<execute()> for Oracle C<CLOB> or C<BLOB> fields. |
677 | Instead, you have to use C<bind_param()>: |
678 | |
679 | $sth->bind_param(1, 'reg data'); |
680 | $sth->bind_param(2, $lots, {ora_type => ORA_CLOB}); |
681 | |
682 | The problem is, B<SQL::Abstract> will normally just return a C<@bind> array, |
683 | which loses track of which field each slot refers to. Fear not. |
684 | |
685 | If you specify C<bindtype> in new, you can determine how C<@bind> is returned. |
686 | Currently, you can specify either C<normal> (default) or C<columns>. If you |
687 | specify C<columns>, you will get an array that looks like this: |
688 | |
689 | my $sql = SQL::Abstract->new(bindtype => 'columns'); |
690 | my($stmt, @bind) = $sql->insert(...); |
691 | |
692 | @bind = ( |
693 | [ 'column1', 'value1' ], |
694 | [ 'column2', 'value2' ], |
695 | [ 'column3', 'value3' ], |
696 | ); |
697 | |
698 | You can then iterate through this manually, using DBI's C<bind_param()>. |
e3f9dff4 |
699 | |
32eab2da |
700 | $sth->prepare($stmt); |
701 | my $i = 1; |
702 | for (@bind) { |
703 | my($col, $data) = @$_; |
704 | if ($col eq 'details' || $col eq 'comments') { |
705 | $sth->bind_param($i, $data, {ora_type => ORA_CLOB}); |
706 | } elsif ($col eq 'image') { |
707 | $sth->bind_param($i, $data, {ora_type => ORA_BLOB}); |
708 | } else { |
709 | $sth->bind_param($i, $data); |
710 | } |
711 | $i++; |
712 | } |
713 | $sth->execute; # execute without @bind now |
714 | |
715 | Now, why would you still use B<SQL::Abstract> if you have to do this crap? |
716 | Basically, the advantage is still that you don't have to care which fields |
717 | are or are not included. You could wrap that above C<for> loop in a simple |
718 | sub called C<bind_fields()> or something and reuse it repeatedly. You still |
719 | get a layer of abstraction over manual SQL specification. |
720 | |
deb148a2 |
721 | Note that if you set L</bindtype> to C<columns>, the C<\[$sql, @bind]> |
722 | construct (see L</Literal SQL with placeholders and bind values (subqueries)>) |
723 | will expect the bind values in this format. |
724 | |
32eab2da |
725 | =item quote_char |
726 | |
727 | This is the character that a table or column name will be quoted |
9d48860e |
728 | with. By default this is an empty string, but you could set it to |
32eab2da |
729 | the character C<`>, to generate SQL like this: |
730 | |
731 | SELECT `a_field` FROM `a_table` WHERE `some_field` LIKE '%someval%' |
732 | |
96449e8e |
733 | Alternatively, you can supply an array ref of two items, the first being the left |
734 | hand quote character, and the second the right hand quote character. For |
735 | example, you could supply C<['[',']']> for SQL Server 2000 compliant quotes |
736 | that generates SQL like this: |
737 | |
738 | SELECT [a_field] FROM [a_table] WHERE [some_field] LIKE '%someval%' |
739 | |
9d48860e |
740 | Quoting is useful if you have tables or columns names that are reserved |
96449e8e |
741 | words in your database's SQL dialect. |
32eab2da |
742 | |
743 | =item name_sep |
744 | |
745 | This is the character that separates a table and column name. It is |
746 | necessary to specify this when the C<quote_char> option is selected, |
747 | so that tables and column names can be individually quoted like this: |
748 | |
749 | SELECT `table`.`one_field` FROM `table` WHERE `table`.`other_field` = 1 |
750 | |
b6251592 |
751 | =item injection_guard |
752 | |
753 | A regular expression C<qr/.../> that is applied to any C<-function> and unquoted |
754 | column name specified in a query structure. This is a safety mechanism to avoid |
755 | injection attacks when mishandling user input e.g.: |
756 | |
757 | my %condition_as_column_value_pairs = get_values_from_user(); |
758 | $sqla->select( ... , \%condition_as_column_value_pairs ); |
759 | |
760 | If the expression matches an exception is thrown. Note that literal SQL |
761 | supplied via C<\'...'> or C<\['...']> is B<not> checked in any way. |
762 | |
763 | Defaults to checking for C<;> and the C<GO> keyword (TransactSQL) |
764 | |
96449e8e |
765 | =item array_datatypes |
32eab2da |
766 | |
9d48860e |
767 | When this option is true, arrayrefs in INSERT or UPDATE are |
768 | interpreted as array datatypes and are passed directly |
96449e8e |
769 | to the DBI layer. |
770 | When this option is false, arrayrefs are interpreted |
771 | as literal SQL, just like refs to arrayrefs |
772 | (but this behavior is for backwards compatibility; when writing |
773 | new queries, use the "reference to arrayref" syntax |
774 | for literal SQL). |
32eab2da |
775 | |
32eab2da |
776 | |
96449e8e |
777 | =item special_ops |
32eab2da |
778 | |
9d48860e |
779 | Takes a reference to a list of "special operators" |
96449e8e |
780 | to extend the syntax understood by L<SQL::Abstract>. |
781 | See section L</"SPECIAL OPERATORS"> for details. |
32eab2da |
782 | |
59f23b3d |
783 | =item unary_ops |
784 | |
9d48860e |
785 | Takes a reference to a list of "unary operators" |
59f23b3d |
786 | to extend the syntax understood by L<SQL::Abstract>. |
787 | See section L</"UNARY OPERATORS"> for details. |
788 | |
32eab2da |
789 | |
32eab2da |
790 | |
96449e8e |
791 | =back |
32eab2da |
792 | |
02288357 |
793 | =head2 insert($table, \@values || \%fieldvals, \%options) |
32eab2da |
794 | |
795 | This is the simplest function. You simply give it a table name |
796 | and either an arrayref of values or hashref of field/value pairs. |
797 | It returns an SQL INSERT statement and a list of bind values. |
96449e8e |
798 | See the sections on L</"Inserting and Updating Arrays"> and |
799 | L</"Inserting and Updating SQL"> for information on how to insert |
800 | with those data types. |
32eab2da |
801 | |
02288357 |
802 | The optional C<\%options> hash reference may contain additional |
803 | options to generate the insert SQL. Currently supported options |
804 | are: |
805 | |
806 | =over 4 |
807 | |
808 | =item returning |
809 | |
810 | Takes either a scalar of raw SQL fields, or an array reference of |
811 | field names, and adds on an SQL C<RETURNING> statement at the end. |
812 | This allows you to return data generated by the insert statement |
813 | (such as row IDs) without performing another C<SELECT> statement. |
814 | Note, however, this is not part of the SQL standard and may not |
815 | be supported by all database engines. |
816 | |
817 | =back |
818 | |
32eab2da |
819 | =head2 update($table, \%fieldvals, \%where) |
820 | |
821 | This takes a table, hashref of field/value pairs, and an optional |
86298391 |
822 | hashref L<WHERE clause|/WHERE CLAUSES>. It returns an SQL UPDATE function and a list |
32eab2da |
823 | of bind values. |
96449e8e |
824 | See the sections on L</"Inserting and Updating Arrays"> and |
825 | L</"Inserting and Updating SQL"> for information on how to insert |
826 | with those data types. |
32eab2da |
827 | |
96449e8e |
828 | =head2 select($source, $fields, $where, $order) |
32eab2da |
829 | |
9d48860e |
830 | This returns a SQL SELECT statement and associated list of bind values, as |
96449e8e |
831 | specified by the arguments : |
32eab2da |
832 | |
96449e8e |
833 | =over |
32eab2da |
834 | |
96449e8e |
835 | =item $source |
32eab2da |
836 | |
9d48860e |
837 | Specification of the 'FROM' part of the statement. |
96449e8e |
838 | The argument can be either a plain scalar (interpreted as a table |
839 | name, will be quoted), or an arrayref (interpreted as a list |
840 | of table names, joined by commas, quoted), or a scalarref |
841 | (literal table name, not quoted), or a ref to an arrayref |
842 | (list of literal table names, joined by commas, not quoted). |
32eab2da |
843 | |
96449e8e |
844 | =item $fields |
32eab2da |
845 | |
9d48860e |
846 | Specification of the list of fields to retrieve from |
96449e8e |
847 | the source. |
848 | The argument can be either an arrayref (interpreted as a list |
9d48860e |
849 | of field names, will be joined by commas and quoted), or a |
96449e8e |
850 | plain scalar (literal SQL, not quoted). |
521647e7 |
851 | Please observe that this API is not as flexible as that of |
852 | the first argument C<$source>, for backwards compatibility reasons. |
32eab2da |
853 | |
96449e8e |
854 | =item $where |
32eab2da |
855 | |
96449e8e |
856 | Optional argument to specify the WHERE part of the query. |
857 | The argument is most often a hashref, but can also be |
9d48860e |
858 | an arrayref or plain scalar -- |
96449e8e |
859 | see section L<WHERE clause|/"WHERE CLAUSES"> for details. |
32eab2da |
860 | |
96449e8e |
861 | =item $order |
32eab2da |
862 | |
96449e8e |
863 | Optional argument to specify the ORDER BY part of the query. |
9d48860e |
864 | The argument can be a scalar, a hashref or an arrayref |
96449e8e |
865 | -- see section L<ORDER BY clause|/"ORDER BY CLAUSES"> |
866 | for details. |
32eab2da |
867 | |
96449e8e |
868 | =back |
32eab2da |
869 | |
32eab2da |
870 | |
871 | =head2 delete($table, \%where) |
872 | |
86298391 |
873 | This takes a table name and optional hashref L<WHERE clause|/WHERE CLAUSES>. |
32eab2da |
874 | It returns an SQL DELETE statement and list of bind values. |
875 | |
32eab2da |
876 | =head2 where(\%where, \@order) |
877 | |
878 | This is used to generate just the WHERE clause. For example, |
879 | if you have an arbitrary data structure and know what the |
880 | rest of your SQL is going to look like, but want an easy way |
881 | to produce a WHERE clause, use this. It returns an SQL WHERE |
882 | clause and list of bind values. |
883 | |
32eab2da |
884 | |
885 | =head2 values(\%data) |
886 | |
887 | This just returns the values from the hash C<%data>, in the same |
888 | order that would be returned from any of the other above queries. |
889 | Using this allows you to markedly speed up your queries if you |
890 | are affecting lots of rows. See below under the L</"PERFORMANCE"> section. |
891 | |
32eab2da |
892 | =head2 generate($any, 'number', $of, \@data, $struct, \%types) |
893 | |
894 | Warning: This is an experimental method and subject to change. |
895 | |
896 | This returns arbitrarily generated SQL. It's a really basic shortcut. |
897 | It will return two different things, depending on return context: |
898 | |
899 | my($stmt, @bind) = $sql->generate('create table', \$table, \@fields); |
900 | my $stmt_and_val = $sql->generate('create table', \$table, \@fields); |
901 | |
902 | These would return the following: |
903 | |
904 | # First calling form |
905 | $stmt = "CREATE TABLE test (?, ?)"; |
906 | @bind = (field1, field2); |
907 | |
908 | # Second calling form |
909 | $stmt_and_val = "CREATE TABLE test (field1, field2)"; |
910 | |
911 | Depending on what you're trying to do, it's up to you to choose the correct |
912 | format. In this example, the second form is what you would want. |
913 | |
914 | By the same token: |
915 | |
916 | $sql->generate('alter session', { nls_date_format => 'MM/YY' }); |
917 | |
918 | Might give you: |
919 | |
920 | ALTER SESSION SET nls_date_format = 'MM/YY' |
921 | |
922 | You get the idea. Strings get their case twiddled, but everything |
923 | else remains verbatim. |
924 | |
32eab2da |
925 | =head1 WHERE CLAUSES |
926 | |
96449e8e |
927 | =head2 Introduction |
928 | |
32eab2da |
929 | This module uses a variation on the idea from L<DBIx::Abstract>. It |
930 | is B<NOT>, repeat I<not> 100% compatible. B<The main logic of this |
931 | module is that things in arrays are OR'ed, and things in hashes |
932 | are AND'ed.> |
933 | |
934 | The easiest way to explain is to show lots of examples. After |
935 | each C<%where> hash shown, it is assumed you used: |
936 | |
937 | my($stmt, @bind) = $sql->where(\%where); |
938 | |
939 | However, note that the C<%where> hash can be used directly in any |
940 | of the other functions as well, as described above. |
941 | |
96449e8e |
942 | =head2 Key-value pairs |
943 | |
32eab2da |
944 | So, let's get started. To begin, a simple hash: |
945 | |
946 | my %where = ( |
947 | user => 'nwiger', |
948 | status => 'completed' |
949 | ); |
950 | |
951 | Is converted to SQL C<key = val> statements: |
952 | |
953 | $stmt = "WHERE user = ? AND status = ?"; |
954 | @bind = ('nwiger', 'completed'); |
955 | |
956 | One common thing I end up doing is having a list of values that |
957 | a field can be in. To do this, simply specify a list inside of |
958 | an arrayref: |
959 | |
960 | my %where = ( |
961 | user => 'nwiger', |
962 | status => ['assigned', 'in-progress', 'pending']; |
963 | ); |
964 | |
965 | This simple code will create the following: |
9d48860e |
966 | |
32eab2da |
967 | $stmt = "WHERE user = ? AND ( status = ? OR status = ? OR status = ? )"; |
968 | @bind = ('nwiger', 'assigned', 'in-progress', 'pending'); |
969 | |
9d48860e |
970 | A field associated to an empty arrayref will be considered a |
7cac25e6 |
971 | logical false and will generate 0=1. |
8a68b5be |
972 | |
b864ba9b |
973 | =head2 Tests for NULL values |
974 | |
975 | If the value part is C<undef> then this is converted to SQL <IS NULL> |
976 | |
977 | my %where = ( |
978 | user => 'nwiger', |
979 | status => undef, |
980 | ); |
981 | |
982 | becomes: |
983 | |
984 | $stmt = "WHERE user = ? AND status IS NULL"; |
985 | @bind = ('nwiger'); |
986 | |
e9614080 |
987 | To test if a column IS NOT NULL: |
988 | |
989 | my %where = ( |
990 | user => 'nwiger', |
991 | status => { '!=', undef }, |
992 | ); |
cc422895 |
993 | |
6e0c6552 |
994 | =head2 Specific comparison operators |
96449e8e |
995 | |
32eab2da |
996 | If you want to specify a different type of operator for your comparison, |
997 | you can use a hashref for a given column: |
998 | |
999 | my %where = ( |
1000 | user => 'nwiger', |
1001 | status => { '!=', 'completed' } |
1002 | ); |
1003 | |
1004 | Which would generate: |
1005 | |
1006 | $stmt = "WHERE user = ? AND status != ?"; |
1007 | @bind = ('nwiger', 'completed'); |
1008 | |
1009 | To test against multiple values, just enclose the values in an arrayref: |
1010 | |
96449e8e |
1011 | status => { '=', ['assigned', 'in-progress', 'pending'] }; |
1012 | |
f2d5020d |
1013 | Which would give you: |
96449e8e |
1014 | |
1015 | "WHERE status = ? OR status = ? OR status = ?" |
1016 | |
1017 | |
1018 | The hashref can also contain multiple pairs, in which case it is expanded |
32eab2da |
1019 | into an C<AND> of its elements: |
1020 | |
1021 | my %where = ( |
1022 | user => 'nwiger', |
1023 | status => { '!=', 'completed', -not_like => 'pending%' } |
1024 | ); |
1025 | |
1026 | # Or more dynamically, like from a form |
1027 | $where{user} = 'nwiger'; |
1028 | $where{status}{'!='} = 'completed'; |
1029 | $where{status}{'-not_like'} = 'pending%'; |
1030 | |
1031 | # Both generate this |
1032 | $stmt = "WHERE user = ? AND status != ? AND status NOT LIKE ?"; |
1033 | @bind = ('nwiger', 'completed', 'pending%'); |
1034 | |
96449e8e |
1035 | |
32eab2da |
1036 | To get an OR instead, you can combine it with the arrayref idea: |
1037 | |
1038 | my %where => ( |
1039 | user => 'nwiger', |
1a6f2a03 |
1040 | priority => [ { '=', 2 }, { '>', 5 } ] |
32eab2da |
1041 | ); |
1042 | |
1043 | Which would generate: |
1044 | |
1a6f2a03 |
1045 | $stmt = "WHERE ( priority = ? OR priority > ? ) AND user = ?"; |
1046 | @bind = ('2', '5', 'nwiger'); |
32eab2da |
1047 | |
44b9e502 |
1048 | If you want to include literal SQL (with or without bind values), just use a |
1049 | scalar reference or array reference as the value: |
1050 | |
1051 | my %where = ( |
1052 | date_entered => { '>' => \["to_date(?, 'MM/DD/YYYY')", "11/26/2008"] }, |
1053 | date_expires => { '<' => \"now()" } |
1054 | ); |
1055 | |
1056 | Which would generate: |
1057 | |
1058 | $stmt = "WHERE date_entered > "to_date(?, 'MM/DD/YYYY') AND date_expires < now()"; |
1059 | @bind = ('11/26/2008'); |
1060 | |
96449e8e |
1061 | |
1062 | =head2 Logic and nesting operators |
1063 | |
1064 | In the example above, |
1065 | there is a subtle trap if you want to say something like |
32eab2da |
1066 | this (notice the C<AND>): |
1067 | |
1068 | WHERE priority != ? AND priority != ? |
1069 | |
1070 | Because, in Perl you I<can't> do this: |
1071 | |
1072 | priority => { '!=', 2, '!=', 1 } |
1073 | |
1074 | As the second C<!=> key will obliterate the first. The solution |
1075 | is to use the special C<-modifier> form inside an arrayref: |
1076 | |
9d48860e |
1077 | priority => [ -and => {'!=', 2}, |
96449e8e |
1078 | {'!=', 1} ] |
1079 | |
32eab2da |
1080 | |
1081 | Normally, these would be joined by C<OR>, but the modifier tells it |
1082 | to use C<AND> instead. (Hint: You can use this in conjunction with the |
1083 | C<logic> option to C<new()> in order to change the way your queries |
1084 | work by default.) B<Important:> Note that the C<-modifier> goes |
1085 | B<INSIDE> the arrayref, as an extra first element. This will |
1086 | B<NOT> do what you think it might: |
1087 | |
1088 | priority => -and => [{'!=', 2}, {'!=', 1}] # WRONG! |
1089 | |
1090 | Here is a quick list of equivalencies, since there is some overlap: |
1091 | |
1092 | # Same |
1093 | status => {'!=', 'completed', 'not like', 'pending%' } |
1094 | status => [ -and => {'!=', 'completed'}, {'not like', 'pending%'}] |
1095 | |
1096 | # Same |
1097 | status => {'=', ['assigned', 'in-progress']} |
1098 | status => [ -or => {'=', 'assigned'}, {'=', 'in-progress'}] |
1099 | status => [ {'=', 'assigned'}, {'=', 'in-progress'} ] |
1100 | |
e3f9dff4 |
1101 | |
1102 | |
96449e8e |
1103 | =head2 Special operators : IN, BETWEEN, etc. |
1104 | |
32eab2da |
1105 | You can also use the hashref format to compare a list of fields using the |
1106 | C<IN> comparison operator, by specifying the list as an arrayref: |
1107 | |
1108 | my %where = ( |
1109 | status => 'completed', |
1110 | reportid => { -in => [567, 2335, 2] } |
1111 | ); |
1112 | |
1113 | Which would generate: |
1114 | |
1115 | $stmt = "WHERE status = ? AND reportid IN (?,?,?)"; |
1116 | @bind = ('completed', '567', '2335', '2'); |
1117 | |
9d48860e |
1118 | The reverse operator C<-not_in> generates SQL C<NOT IN> and is used in |
96449e8e |
1119 | the same way. |
1120 | |
6e0c6552 |
1121 | If the argument to C<-in> is an empty array, 'sqlfalse' is generated |
1122 | (by default : C<1=0>). Similarly, C<< -not_in => [] >> generates |
1123 | 'sqltrue' (by default : C<1=1>). |
1124 | |
e41c3bdd |
1125 | In addition to the array you can supply a chunk of literal sql or |
1126 | literal sql with bind: |
6e0c6552 |
1127 | |
e41c3bdd |
1128 | my %where = { |
1129 | customer => { -in => \[ |
1130 | 'SELECT cust_id FROM cust WHERE balance > ?', |
1131 | 2000, |
1132 | ], |
1133 | status => { -in => \'SELECT status_codes FROM states' }, |
1134 | }; |
6e0c6552 |
1135 | |
e41c3bdd |
1136 | would generate: |
1137 | |
1138 | $stmt = "WHERE ( |
1139 | customer IN ( SELECT cust_id FROM cust WHERE balance > ? ) |
1140 | AND status IN ( SELECT status_codes FROM states ) |
1141 | )"; |
1142 | @bind = ('2000'); |
1143 | |
0dfd2442 |
1144 | Finally, if the argument to C<-in> is not a reference, it will be |
1145 | treated as a single-element array. |
e41c3bdd |
1146 | |
1147 | Another pair of operators is C<-between> and C<-not_between>, |
96449e8e |
1148 | used with an arrayref of two values: |
32eab2da |
1149 | |
1150 | my %where = ( |
1151 | user => 'nwiger', |
1152 | completion_date => { |
1153 | -not_between => ['2002-10-01', '2003-02-06'] |
1154 | } |
1155 | ); |
1156 | |
1157 | Would give you: |
1158 | |
1159 | WHERE user = ? AND completion_date NOT BETWEEN ( ? AND ? ) |
1160 | |
e41c3bdd |
1161 | Just like with C<-in> all plausible combinations of literal SQL |
1162 | are possible: |
1163 | |
1164 | my %where = { |
1165 | start0 => { -between => [ 1, 2 ] }, |
1166 | start1 => { -between => \["? AND ?", 1, 2] }, |
1167 | start2 => { -between => \"lower(x) AND upper(y)" }, |
9d48860e |
1168 | start3 => { -between => [ |
e41c3bdd |
1169 | \"lower(x)", |
1170 | \["upper(?)", 'stuff' ], |
1171 | ] }, |
1172 | }; |
1173 | |
1174 | Would give you: |
1175 | |
1176 | $stmt = "WHERE ( |
1177 | ( start0 BETWEEN ? AND ? ) |
1178 | AND ( start1 BETWEEN ? AND ? ) |
1179 | AND ( start2 BETWEEN lower(x) AND upper(y) ) |
1180 | AND ( start3 BETWEEN lower(x) AND upper(?) ) |
1181 | )"; |
1182 | @bind = (1, 2, 1, 2, 'stuff'); |
1183 | |
1184 | |
9d48860e |
1185 | These are the two builtin "special operators"; but the |
96449e8e |
1186 | list can be expanded : see section L</"SPECIAL OPERATORS"> below. |
1187 | |
59f23b3d |
1188 | =head2 Unary operators: bool |
97a920ef |
1189 | |
1190 | If you wish to test against boolean columns or functions within your |
1191 | database you can use the C<-bool> and C<-not_bool> operators. For |
1192 | example to test the column C<is_user> being true and the column |
827bb0eb |
1193 | C<is_enabled> being false you would use:- |
97a920ef |
1194 | |
1195 | my %where = ( |
1196 | -bool => 'is_user', |
1197 | -not_bool => 'is_enabled', |
1198 | ); |
1199 | |
1200 | Would give you: |
1201 | |
277b5d3f |
1202 | WHERE is_user AND NOT is_enabled |
97a920ef |
1203 | |
0b604e9d |
1204 | If a more complex combination is required, testing more conditions, |
1205 | then you should use the and/or operators:- |
1206 | |
1207 | my %where = ( |
1208 | -and => [ |
1209 | -bool => 'one', |
23401b81 |
1210 | -not_bool => { two=> { -rlike => 'bar' } }, |
1211 | -not_bool => { three => [ { '=', 2 }, { '>', 5 } ] }, |
0b604e9d |
1212 | ], |
1213 | ); |
1214 | |
1215 | Would give you: |
1216 | |
23401b81 |
1217 | WHERE |
1218 | one |
1219 | AND |
1220 | (NOT two RLIKE ?) |
1221 | AND |
1222 | (NOT ( three = ? OR three > ? )) |
97a920ef |
1223 | |
1224 | |
107b72f1 |
1225 | =head2 Nested conditions, -and/-or prefixes |
96449e8e |
1226 | |
32eab2da |
1227 | So far, we've seen how multiple conditions are joined with a top-level |
1228 | C<AND>. We can change this by putting the different conditions we want in |
1229 | hashes and then putting those hashes in an array. For example: |
1230 | |
1231 | my @where = ( |
1232 | { |
1233 | user => 'nwiger', |
1234 | status => { -like => ['pending%', 'dispatched'] }, |
1235 | }, |
1236 | { |
1237 | user => 'robot', |
1238 | status => 'unassigned', |
1239 | } |
1240 | ); |
1241 | |
1242 | This data structure would create the following: |
1243 | |
1244 | $stmt = "WHERE ( user = ? AND ( status LIKE ? OR status LIKE ? ) ) |
1245 | OR ( user = ? AND status = ? ) )"; |
1246 | @bind = ('nwiger', 'pending', 'dispatched', 'robot', 'unassigned'); |
1247 | |
107b72f1 |
1248 | |
48d9f5f8 |
1249 | Clauses in hashrefs or arrayrefs can be prefixed with an C<-and> or C<-or> |
1250 | to change the logic inside : |
32eab2da |
1251 | |
1252 | my @where = ( |
1253 | -and => [ |
1254 | user => 'nwiger', |
48d9f5f8 |
1255 | [ |
1256 | -and => [ workhrs => {'>', 20}, geo => 'ASIA' ], |
1257 | -or => { workhrs => {'<', 50}, geo => 'EURO' }, |
32eab2da |
1258 | ], |
1259 | ], |
1260 | ); |
1261 | |
1262 | That would yield: |
1263 | |
48d9f5f8 |
1264 | WHERE ( user = ? AND ( |
1265 | ( workhrs > ? AND geo = ? ) |
1266 | OR ( workhrs < ? OR geo = ? ) |
1267 | ) ) |
107b72f1 |
1268 | |
cc422895 |
1269 | =head3 Algebraic inconsistency, for historical reasons |
107b72f1 |
1270 | |
7cac25e6 |
1271 | C<Important note>: when connecting several conditions, the C<-and->|C<-or> |
1272 | operator goes C<outside> of the nested structure; whereas when connecting |
1273 | several constraints on one column, the C<-and> operator goes |
1274 | C<inside> the arrayref. Here is an example combining both features : |
1275 | |
1276 | my @where = ( |
1277 | -and => [a => 1, b => 2], |
1278 | -or => [c => 3, d => 4], |
1279 | e => [-and => {-like => 'foo%'}, {-like => '%bar'} ] |
1280 | ) |
1281 | |
1282 | yielding |
1283 | |
9d48860e |
1284 | WHERE ( ( ( a = ? AND b = ? ) |
1285 | OR ( c = ? OR d = ? ) |
7cac25e6 |
1286 | OR ( e LIKE ? AND e LIKE ? ) ) ) |
1287 | |
107b72f1 |
1288 | This difference in syntax is unfortunate but must be preserved for |
1289 | historical reasons. So be careful : the two examples below would |
1290 | seem algebraically equivalent, but they are not |
1291 | |
9d48860e |
1292 | {col => [-and => {-like => 'foo%'}, {-like => '%bar'}]} |
107b72f1 |
1293 | # yields : WHERE ( ( col LIKE ? AND col LIKE ? ) ) |
1294 | |
9d48860e |
1295 | [-and => {col => {-like => 'foo%'}, {col => {-like => '%bar'}}]] |
107b72f1 |
1296 | # yields : WHERE ( ( col LIKE ? OR col LIKE ? ) ) |
1297 | |
7cac25e6 |
1298 | |
cc422895 |
1299 | =head2 Literal SQL and value type operators |
96449e8e |
1300 | |
cc422895 |
1301 | The basic premise of SQL::Abstract is that in WHERE specifications the "left |
1302 | side" is a column name and the "right side" is a value (normally rendered as |
1303 | a placeholder). This holds true for both hashrefs and arrayref pairs as you |
1304 | see in the L</WHERE CLAUSES> examples above. Sometimes it is necessary to |
1305 | alter this behavior. There are several ways of doing so. |
e9614080 |
1306 | |
cc422895 |
1307 | =head3 -ident |
1308 | |
1309 | This is a virtual operator that signals the string to its right side is an |
1310 | identifier (a column name) and not a value. For example to compare two |
1311 | columns you would write: |
32eab2da |
1312 | |
e9614080 |
1313 | my %where = ( |
1314 | priority => { '<', 2 }, |
cc422895 |
1315 | requestor => { -ident => 'submitter' }, |
e9614080 |
1316 | ); |
1317 | |
1318 | which creates: |
1319 | |
1320 | $stmt = "WHERE priority < ? AND requestor = submitter"; |
1321 | @bind = ('2'); |
1322 | |
cc422895 |
1323 | If you are maintaining legacy code you may see a different construct as |
1324 | described in L</Deprecated usage of Literal SQL>, please use C<-ident> in new |
1325 | code. |
1326 | |
1327 | =head3 -value |
e9614080 |
1328 | |
cc422895 |
1329 | This is a virtual operator that signals that the construct to its right side |
1330 | is a value to be passed to DBI. This is for example necessary when you want |
1331 | to write a where clause against an array (for RDBMS that support such |
1332 | datatypes). For example: |
e9614080 |
1333 | |
32eab2da |
1334 | my %where = ( |
cc422895 |
1335 | array => { -value => [1, 2, 3] } |
32eab2da |
1336 | ); |
1337 | |
cc422895 |
1338 | will result in: |
32eab2da |
1339 | |
cc422895 |
1340 | $stmt = 'WHERE array = ?'; |
1341 | @bind = ([1, 2, 3]); |
32eab2da |
1342 | |
cc422895 |
1343 | Note that if you were to simply say: |
32eab2da |
1344 | |
1345 | my %where = ( |
cc422895 |
1346 | array => [1, 2, 3] |
32eab2da |
1347 | ); |
1348 | |
3af02ccb |
1349 | the result would probably not be what you wanted: |
cc422895 |
1350 | |
1351 | $stmt = 'WHERE array = ? OR array = ? OR array = ?'; |
1352 | @bind = (1, 2, 3); |
1353 | |
1354 | =head3 Literal SQL |
96449e8e |
1355 | |
cc422895 |
1356 | Finally, sometimes only literal SQL will do. To include a random snippet |
1357 | of SQL verbatim, you specify it as a scalar reference. Consider this only |
1358 | as a last resort. Usually there is a better way. For example: |
96449e8e |
1359 | |
1360 | my %where = ( |
cc422895 |
1361 | priority => { '<', 2 }, |
1362 | requestor => { -in => \'(SELECT name FROM hitmen)' }, |
96449e8e |
1363 | ); |
1364 | |
cc422895 |
1365 | Would create: |
96449e8e |
1366 | |
cc422895 |
1367 | $stmt = "WHERE priority < ? AND requestor IN (SELECT name FROM hitmen)" |
1368 | @bind = (2); |
1369 | |
1370 | Note that in this example, you only get one bind parameter back, since |
1371 | the verbatim SQL is passed as part of the statement. |
1372 | |
1373 | =head4 CAVEAT |
1374 | |
1375 | Never use untrusted input as a literal SQL argument - this is a massive |
1376 | security risk (there is no way to check literal snippets for SQL |
1377 | injections and other nastyness). If you need to deal with untrusted input |
1378 | use literal SQL with placeholders as described next. |
96449e8e |
1379 | |
cc422895 |
1380 | =head3 Literal SQL with placeholders and bind values (subqueries) |
96449e8e |
1381 | |
1382 | If the literal SQL to be inserted has placeholders and bind values, |
1383 | use a reference to an arrayref (yes this is a double reference -- |
1384 | not so common, but perfectly legal Perl). For example, to find a date |
1385 | in Postgres you can use something like this: |
1386 | |
1387 | my %where = ( |
1388 | date_column => \[q/= date '2008-09-30' - ?::integer/, 10/] |
1389 | ) |
1390 | |
1391 | This would create: |
1392 | |
d2a8fe1a |
1393 | $stmt = "WHERE ( date_column = date '2008-09-30' - ?::integer )" |
96449e8e |
1394 | @bind = ('10'); |
1395 | |
deb148a2 |
1396 | Note that you must pass the bind values in the same format as they are returned |
62552e7d |
1397 | by L</where>. That means that if you set L</bindtype> to C<columns>, you must |
26f2dca5 |
1398 | provide the bind values in the C<< [ column_meta => value ] >> format, where |
1399 | C<column_meta> is an opaque scalar value; most commonly the column name, but |
62552e7d |
1400 | you can use any scalar value (including references and blessed references), |
1401 | L<SQL::Abstract> will simply pass it through intact. So if C<bindtype> is set |
1402 | to C<columns> the above example will look like: |
deb148a2 |
1403 | |
1404 | my %where = ( |
1405 | date_column => \[q/= date '2008-09-30' - ?::integer/, [ dummy => 10 ]/] |
1406 | ) |
96449e8e |
1407 | |
1408 | Literal SQL is especially useful for nesting parenthesized clauses in the |
1409 | main SQL query. Here is a first example : |
1410 | |
1411 | my ($sub_stmt, @sub_bind) = ("SELECT c1 FROM t1 WHERE c2 < ? AND c3 LIKE ?", |
1412 | 100, "foo%"); |
1413 | my %where = ( |
1414 | foo => 1234, |
1415 | bar => \["IN ($sub_stmt)" => @sub_bind], |
1416 | ); |
1417 | |
1418 | This yields : |
1419 | |
9d48860e |
1420 | $stmt = "WHERE (foo = ? AND bar IN (SELECT c1 FROM t1 |
96449e8e |
1421 | WHERE c2 < ? AND c3 LIKE ?))"; |
1422 | @bind = (1234, 100, "foo%"); |
1423 | |
9d48860e |
1424 | Other subquery operators, like for example C<"E<gt> ALL"> or C<"NOT IN">, |
96449e8e |
1425 | are expressed in the same way. Of course the C<$sub_stmt> and |
9d48860e |
1426 | its associated bind values can be generated through a former call |
96449e8e |
1427 | to C<select()> : |
1428 | |
1429 | my ($sub_stmt, @sub_bind) |
9d48860e |
1430 | = $sql->select("t1", "c1", {c2 => {"<" => 100}, |
96449e8e |
1431 | c3 => {-like => "foo%"}}); |
1432 | my %where = ( |
1433 | foo => 1234, |
1434 | bar => \["> ALL ($sub_stmt)" => @sub_bind], |
1435 | ); |
1436 | |
1437 | In the examples above, the subquery was used as an operator on a column; |
9d48860e |
1438 | but the same principle also applies for a clause within the main C<%where> |
96449e8e |
1439 | hash, like an EXISTS subquery : |
1440 | |
9d48860e |
1441 | my ($sub_stmt, @sub_bind) |
96449e8e |
1442 | = $sql->select("t1", "*", {c1 => 1, c2 => \"> t0.c0"}); |
48d9f5f8 |
1443 | my %where = ( -and => [ |
96449e8e |
1444 | foo => 1234, |
48d9f5f8 |
1445 | \["EXISTS ($sub_stmt)" => @sub_bind], |
1446 | ]); |
96449e8e |
1447 | |
1448 | which yields |
1449 | |
9d48860e |
1450 | $stmt = "WHERE (foo = ? AND EXISTS (SELECT * FROM t1 |
96449e8e |
1451 | WHERE c1 = ? AND c2 > t0.c0))"; |
1452 | @bind = (1234, 1); |
1453 | |
1454 | |
9d48860e |
1455 | Observe that the condition on C<c2> in the subquery refers to |
1456 | column C<t0.c0> of the main query : this is I<not> a bind |
1457 | value, so we have to express it through a scalar ref. |
96449e8e |
1458 | Writing C<< c2 => {">" => "t0.c0"} >> would have generated |
1459 | C<< c2 > ? >> with bind value C<"t0.c0"> ... not exactly |
1460 | what we wanted here. |
1461 | |
96449e8e |
1462 | Finally, here is an example where a subquery is used |
1463 | for expressing unary negation: |
1464 | |
9d48860e |
1465 | my ($sub_stmt, @sub_bind) |
96449e8e |
1466 | = $sql->where({age => [{"<" => 10}, {">" => 20}]}); |
1467 | $sub_stmt =~ s/^ where //i; # don't want "WHERE" in the subclause |
1468 | my %where = ( |
1469 | lname => {like => '%son%'}, |
48d9f5f8 |
1470 | \["NOT ($sub_stmt)" => @sub_bind], |
96449e8e |
1471 | ); |
1472 | |
1473 | This yields |
1474 | |
1475 | $stmt = "lname LIKE ? AND NOT ( age < ? OR age > ? )" |
1476 | @bind = ('%son%', 10, 20) |
1477 | |
cc422895 |
1478 | =head3 Deprecated usage of Literal SQL |
1479 | |
1480 | Below are some examples of archaic use of literal SQL. It is shown only as |
1481 | reference for those who deal with legacy code. Each example has a much |
1482 | better, cleaner and safer alternative that users should opt for in new code. |
1483 | |
1484 | =over |
1485 | |
1486 | =item * |
1487 | |
1488 | my %where = ( requestor => \'IS NOT NULL' ) |
1489 | |
1490 | $stmt = "WHERE requestor IS NOT NULL" |
1491 | |
1492 | This used to be the way of generating NULL comparisons, before the handling |
1493 | of C<undef> got formalized. For new code please use the superior syntax as |
1494 | described in L</Tests for NULL values>. |
96449e8e |
1495 | |
cc422895 |
1496 | =item * |
1497 | |
1498 | my %where = ( requestor => \'= submitter' ) |
1499 | |
1500 | $stmt = "WHERE requestor = submitter" |
1501 | |
1502 | This used to be the only way to compare columns. Use the superior L</-ident> |
1503 | method for all new code. For example an identifier declared in such a way |
1504 | will be properly quoted if L</quote_char> is properly set, while the legacy |
1505 | form will remain as supplied. |
1506 | |
1507 | =item * |
1508 | |
1509 | my %where = ( is_ready => \"", completed => { '>', '2012-12-21' } ) |
1510 | |
1511 | $stmt = "WHERE completed > ? AND is_ready" |
1512 | @bind = ('2012-12-21') |
1513 | |
1514 | Using an empty string literal used to be the only way to express a boolean. |
1515 | For all new code please use the much more readable |
1516 | L<-bool|/Unary operators: bool> operator. |
1517 | |
1518 | =back |
96449e8e |
1519 | |
1520 | =head2 Conclusion |
1521 | |
32eab2da |
1522 | These pages could go on for a while, since the nesting of the data |
1523 | structures this module can handle are pretty much unlimited (the |
1524 | module implements the C<WHERE> expansion as a recursive function |
1525 | internally). Your best bet is to "play around" with the module a |
1526 | little to see how the data structures behave, and choose the best |
1527 | format for your data based on that. |
1528 | |
1529 | And of course, all the values above will probably be replaced with |
1530 | variables gotten from forms or the command line. After all, if you |
1531 | knew everything ahead of time, you wouldn't have to worry about |
1532 | dynamically-generating SQL and could just hardwire it into your |
1533 | script. |
1534 | |
86298391 |
1535 | =head1 ORDER BY CLAUSES |
1536 | |
9d48860e |
1537 | Some functions take an order by clause. This can either be a scalar (just a |
86298391 |
1538 | column name,) a hash of C<< { -desc => 'col' } >> or C<< { -asc => 'col' } >>, |
1cfa1db3 |
1539 | or an array of either of the two previous forms. Examples: |
1540 | |
952f9e2d |
1541 | Given | Will Generate |
1cfa1db3 |
1542 | ---------------------------------------------------------- |
952f9e2d |
1543 | | |
1544 | \'colA DESC' | ORDER BY colA DESC |
1545 | | |
1546 | 'colA' | ORDER BY colA |
1547 | | |
1548 | [qw/colA colB/] | ORDER BY colA, colB |
1549 | | |
1550 | {-asc => 'colA'} | ORDER BY colA ASC |
1551 | | |
1552 | {-desc => 'colB'} | ORDER BY colB DESC |
1553 | | |
1554 | ['colA', {-asc => 'colB'}] | ORDER BY colA, colB ASC |
1555 | | |
855e6047 |
1556 | { -asc => [qw/colA colB/] } | ORDER BY colA ASC, colB ASC |
952f9e2d |
1557 | | |
1558 | [ | |
1559 | { -asc => 'colA' }, | ORDER BY colA ASC, colB DESC, |
1560 | { -desc => [qw/colB/], | colC ASC, colD ASC |
1561 | { -asc => [qw/colC colD/],| |
1562 | ] | |
1563 | =========================================================== |
86298391 |
1564 | |
96449e8e |
1565 | |
1566 | |
1567 | =head1 SPECIAL OPERATORS |
1568 | |
e3f9dff4 |
1569 | my $sqlmaker = SQL::Abstract->new(special_ops => [ |
3a2e1a5e |
1570 | { |
1571 | regex => qr/.../, |
e3f9dff4 |
1572 | handler => sub { |
1573 | my ($self, $field, $op, $arg) = @_; |
1574 | ... |
3a2e1a5e |
1575 | }, |
1576 | }, |
1577 | { |
1578 | regex => qr/.../, |
1579 | handler => 'method_name', |
e3f9dff4 |
1580 | }, |
1581 | ]); |
1582 | |
9d48860e |
1583 | A "special operator" is a SQL syntactic clause that can be |
e3f9dff4 |
1584 | applied to a field, instead of a usual binary operator. |
9d48860e |
1585 | For example : |
e3f9dff4 |
1586 | |
1587 | WHERE field IN (?, ?, ?) |
1588 | WHERE field BETWEEN ? AND ? |
1589 | WHERE MATCH(field) AGAINST (?, ?) |
96449e8e |
1590 | |
e3f9dff4 |
1591 | Special operators IN and BETWEEN are fairly standard and therefore |
3a2e1a5e |
1592 | are builtin within C<SQL::Abstract> (as the overridable methods |
1593 | C<_where_field_IN> and C<_where_field_BETWEEN>). For other operators, |
1594 | like the MATCH .. AGAINST example above which is specific to MySQL, |
1595 | you can write your own operator handlers - supply a C<special_ops> |
1596 | argument to the C<new> method. That argument takes an arrayref of |
1597 | operator definitions; each operator definition is a hashref with two |
1598 | entries: |
96449e8e |
1599 | |
e3f9dff4 |
1600 | =over |
1601 | |
1602 | =item regex |
1603 | |
1604 | the regular expression to match the operator |
96449e8e |
1605 | |
e3f9dff4 |
1606 | =item handler |
1607 | |
3a2e1a5e |
1608 | Either a coderef or a plain scalar method name. In both cases |
1609 | the expected return is C<< ($sql, @bind) >>. |
1610 | |
1611 | When supplied with a method name, it is simply called on the |
1612 | L<SQL::Abstract/> object as: |
1613 | |
1614 | $self->$method_name ($field, $op, $arg) |
1615 | |
1616 | Where: |
1617 | |
1618 | $op is the part that matched the handler regex |
1619 | $field is the LHS of the operator |
1620 | $arg is the RHS |
1621 | |
1622 | When supplied with a coderef, it is called as: |
1623 | |
1624 | $coderef->($self, $field, $op, $arg) |
1625 | |
e3f9dff4 |
1626 | |
1627 | =back |
1628 | |
9d48860e |
1629 | For example, here is an implementation |
e3f9dff4 |
1630 | of the MATCH .. AGAINST syntax for MySQL |
1631 | |
1632 | my $sqlmaker = SQL::Abstract->new(special_ops => [ |
9d48860e |
1633 | |
e3f9dff4 |
1634 | # special op for MySql MATCH (field) AGAINST(word1, word2, ...) |
9d48860e |
1635 | {regex => qr/^match$/i, |
e3f9dff4 |
1636 | handler => sub { |
1637 | my ($self, $field, $op, $arg) = @_; |
1638 | $arg = [$arg] if not ref $arg; |
1639 | my $label = $self->_quote($field); |
1640 | my ($placeholder) = $self->_convert('?'); |
1641 | my $placeholders = join ", ", (($placeholder) x @$arg); |
1642 | my $sql = $self->_sqlcase('match') . " ($label) " |
1643 | . $self->_sqlcase('against') . " ($placeholders) "; |
1644 | my @bind = $self->_bindtype($field, @$arg); |
1645 | return ($sql, @bind); |
1646 | } |
1647 | }, |
9d48860e |
1648 | |
e3f9dff4 |
1649 | ]); |
96449e8e |
1650 | |
1651 | |
59f23b3d |
1652 | =head1 UNARY OPERATORS |
1653 | |
112b5232 |
1654 | my $sqlmaker = SQL::Abstract->new(unary_ops => [ |
59f23b3d |
1655 | { |
1656 | regex => qr/.../, |
1657 | handler => sub { |
1658 | my ($self, $op, $arg) = @_; |
1659 | ... |
1660 | }, |
1661 | }, |
1662 | { |
1663 | regex => qr/.../, |
1664 | handler => 'method_name', |
1665 | }, |
1666 | ]); |
1667 | |
9d48860e |
1668 | A "unary operator" is a SQL syntactic clause that can be |
59f23b3d |
1669 | applied to a field - the operator goes before the field |
1670 | |
1671 | You can write your own operator handlers - supply a C<unary_ops> |
1672 | argument to the C<new> method. That argument takes an arrayref of |
1673 | operator definitions; each operator definition is a hashref with two |
1674 | entries: |
1675 | |
1676 | =over |
1677 | |
1678 | =item regex |
1679 | |
1680 | the regular expression to match the operator |
1681 | |
1682 | =item handler |
1683 | |
1684 | Either a coderef or a plain scalar method name. In both cases |
1685 | the expected return is C<< $sql >>. |
1686 | |
1687 | When supplied with a method name, it is simply called on the |
1688 | L<SQL::Abstract/> object as: |
1689 | |
1690 | $self->$method_name ($op, $arg) |
1691 | |
1692 | Where: |
1693 | |
1694 | $op is the part that matched the handler regex |
1695 | $arg is the RHS or argument of the operator |
1696 | |
1697 | When supplied with a coderef, it is called as: |
1698 | |
1699 | $coderef->($self, $op, $arg) |
1700 | |
1701 | |
1702 | =back |
1703 | |
1704 | |
32eab2da |
1705 | =head1 PERFORMANCE |
1706 | |
1707 | Thanks to some benchmarking by Mark Stosberg, it turns out that |
1708 | this module is many orders of magnitude faster than using C<DBIx::Abstract>. |
1709 | I must admit this wasn't an intentional design issue, but it's a |
1710 | byproduct of the fact that you get to control your C<DBI> handles |
1711 | yourself. |
1712 | |
1713 | To maximize performance, use a code snippet like the following: |
1714 | |
1715 | # prepare a statement handle using the first row |
1716 | # and then reuse it for the rest of the rows |
1717 | my($sth, $stmt); |
1718 | for my $href (@array_of_hashrefs) { |
1719 | $stmt ||= $sql->insert('table', $href); |
1720 | $sth ||= $dbh->prepare($stmt); |
1721 | $sth->execute($sql->values($href)); |
1722 | } |
1723 | |
1724 | The reason this works is because the keys in your C<$href> are sorted |
1725 | internally by B<SQL::Abstract>. Thus, as long as your data retains |
1726 | the same structure, you only have to generate the SQL the first time |
1727 | around. On subsequent queries, simply use the C<values> function provided |
1728 | by this module to return your values in the correct order. |
1729 | |
b864ba9b |
1730 | However this depends on the values having the same type - if, for |
1731 | example, the values of a where clause may either have values |
1732 | (resulting in sql of the form C<column = ?> with a single bind |
1733 | value), or alternatively the values might be C<undef> (resulting in |
1734 | sql of the form C<column IS NULL> with no bind value) then the |
1735 | caching technique suggested will not work. |
96449e8e |
1736 | |
32eab2da |
1737 | =head1 FORMBUILDER |
1738 | |
1739 | If you use my C<CGI::FormBuilder> module at all, you'll hopefully |
1740 | really like this part (I do, at least). Building up a complex query |
1741 | can be as simple as the following: |
1742 | |
1743 | #!/usr/bin/perl |
1744 | |
46dc2f3e |
1745 | use warnings; |
1746 | use strict; |
1747 | |
32eab2da |
1748 | use CGI::FormBuilder; |
1749 | use SQL::Abstract; |
1750 | |
1751 | my $form = CGI::FormBuilder->new(...); |
1752 | my $sql = SQL::Abstract->new; |
1753 | |
1754 | if ($form->submitted) { |
1755 | my $field = $form->field; |
1756 | my $id = delete $field->{id}; |
1757 | my($stmt, @bind) = $sql->update('table', $field, {id => $id}); |
1758 | } |
1759 | |
1760 | Of course, you would still have to connect using C<DBI> to run the |
1761 | query, but the point is that if you make your form look like your |
1762 | table, the actual query script can be extremely simplistic. |
1763 | |
1764 | If you're B<REALLY> lazy (I am), check out C<HTML::QuickTable> for |
9d48860e |
1765 | a fast interface to returning and formatting data. I frequently |
32eab2da |
1766 | use these three modules together to write complex database query |
1767 | apps in under 50 lines. |
1768 | |
d8cc1792 |
1769 | =head1 REPO |
1770 | |
1771 | =over |
1772 | |
6d19fbf9 |
1773 | =item * gitweb: L<http://git.shadowcat.co.uk/gitweb/gitweb.cgi?p=dbsrgits/SQL-Abstract.git> |
d8cc1792 |
1774 | |
6d19fbf9 |
1775 | =item * git: L<git://git.shadowcat.co.uk/dbsrgits/SQL-Abstract.git> |
d8cc1792 |
1776 | |
1777 | =back |
32eab2da |
1778 | |
96449e8e |
1779 | =head1 CHANGES |
1780 | |
1781 | Version 1.50 was a major internal refactoring of C<SQL::Abstract>. |
1782 | Great care has been taken to preserve the I<published> behavior |
1783 | documented in previous versions in the 1.* family; however, |
9d48860e |
1784 | some features that were previously undocumented, or behaved |
96449e8e |
1785 | differently from the documentation, had to be changed in order |
1786 | to clarify the semantics. Hence, client code that was relying |
9d48860e |
1787 | on some dark areas of C<SQL::Abstract> v1.* |
96449e8e |
1788 | B<might behave differently> in v1.50. |
32eab2da |
1789 | |
d2a8fe1a |
1790 | The main changes are : |
1791 | |
96449e8e |
1792 | =over |
32eab2da |
1793 | |
9d48860e |
1794 | =item * |
32eab2da |
1795 | |
96449e8e |
1796 | support for literal SQL through the C<< \ [$sql, bind] >> syntax. |
1797 | |
1798 | =item * |
1799 | |
145fbfc8 |
1800 | support for the { operator => \"..." } construct (to embed literal SQL) |
1801 | |
1802 | =item * |
1803 | |
9c37b9c0 |
1804 | support for the { operator => \["...", @bind] } construct (to embed literal SQL with bind values) |
1805 | |
1806 | =item * |
1807 | |
96449e8e |
1808 | optional support for L<array datatypes|/"Inserting and Updating Arrays"> |
1809 | |
9d48860e |
1810 | =item * |
96449e8e |
1811 | |
1812 | defensive programming : check arguments |
1813 | |
1814 | =item * |
1815 | |
1816 | fixed bug with global logic, which was previously implemented |
7cac25e6 |
1817 | through global variables yielding side-effects. Prior versions would |
96449e8e |
1818 | interpret C<< [ {cond1, cond2}, [cond3, cond4] ] >> |
1819 | as C<< "(cond1 AND cond2) OR (cond3 AND cond4)" >>. |
1820 | Now this is interpreted |
1821 | as C<< "(cond1 AND cond2) OR (cond3 OR cond4)" >>. |
1822 | |
96449e8e |
1823 | |
1824 | =item * |
1825 | |
1826 | fixed semantics of _bindtype on array args |
1827 | |
9d48860e |
1828 | =item * |
96449e8e |
1829 | |
1830 | dropped the C<_anoncopy> of the %where tree. No longer necessary, |
1831 | we just avoid shifting arrays within that tree. |
1832 | |
1833 | =item * |
1834 | |
1835 | dropped the C<_modlogic> function |
1836 | |
1837 | =back |
32eab2da |
1838 | |
32eab2da |
1839 | =head1 ACKNOWLEDGEMENTS |
1840 | |
1841 | There are a number of individuals that have really helped out with |
1842 | this module. Unfortunately, most of them submitted bugs via CPAN |
1843 | so I have no idea who they are! But the people I do know are: |
1844 | |
9d48860e |
1845 | Ash Berlin (order_by hash term support) |
b643abe1 |
1846 | Matt Trout (DBIx::Class support) |
32eab2da |
1847 | Mark Stosberg (benchmarking) |
1848 | Chas Owens (initial "IN" operator support) |
1849 | Philip Collins (per-field SQL functions) |
1850 | Eric Kolve (hashref "AND" support) |
1851 | Mike Fragassi (enhancements to "BETWEEN" and "LIKE") |
1852 | Dan Kubb (support for "quote_char" and "name_sep") |
f5aab26e |
1853 | Guillermo Roditi (patch to cleanup "IN" and "BETWEEN", fix and tests for _order_by) |
48d9f5f8 |
1854 | Laurent Dami (internal refactoring, extensible list of special operators, literal SQL) |
dbdf7648 |
1855 | Norbert Buchmuller (support for literal SQL in hashpair, misc. fixes & tests) |
e96c510a |
1856 | Peter Rabbitson (rewrite of SQLA::Test, misc. fixes & tests) |
02288357 |
1857 | Oliver Charles (support for "RETURNING" after "INSERT") |
32eab2da |
1858 | |
1859 | Thanks! |
1860 | |
32eab2da |
1861 | =head1 SEE ALSO |
1862 | |
86298391 |
1863 | L<DBIx::Class>, L<DBIx::Abstract>, L<CGI::FormBuilder>, L<HTML::QuickTable>. |
32eab2da |
1864 | |
32eab2da |
1865 | =head1 AUTHOR |
1866 | |
b643abe1 |
1867 | Copyright (c) 2001-2007 Nathan Wiger <nwiger@cpan.org>. All Rights Reserved. |
1868 | |
1869 | This module is actively maintained by Matt Trout <mst@shadowcatsystems.co.uk> |
32eab2da |
1870 | |
abe72f94 |
1871 | For support, your best bet is to try the C<DBIx::Class> users mailing list. |
1872 | While not an official support venue, C<DBIx::Class> makes heavy use of |
1873 | C<SQL::Abstract>, and as such list members there are very familiar with |
1874 | how to create queries. |
1875 | |
0d067ded |
1876 | =head1 LICENSE |
1877 | |
d988ab87 |
1878 | This module is free software; you may copy this under the same |
1879 | terms as perl itself (either the GNU General Public License or |
1880 | the Artistic License) |
32eab2da |
1881 | |
1882 | =cut |
1883 | |