Commit | Line | Data |
32eab2da |
1 | |
2 | package SQL::Abstract; |
3 | |
4 | =head1 NAME |
5 | |
6 | SQL::Abstract - Generate SQL from Perl data structures |
7 | |
8 | =head1 SYNOPSIS |
9 | |
10 | use SQL::Abstract; |
11 | |
12 | my $sql = SQL::Abstract->new; |
13 | |
14 | my($stmt, @bind) = $sql->select($table, \@fields, \%where, \@order); |
15 | |
16 | my($stmt, @bind) = $sql->insert($table, \%fieldvals || \@values); |
17 | |
18 | my($stmt, @bind) = $sql->update($table, \%fieldvals, \%where); |
19 | |
20 | my($stmt, @bind) = $sql->delete($table, \%where); |
21 | |
22 | # Then, use these in your DBI statements |
23 | my $sth = $dbh->prepare($stmt); |
24 | $sth->execute(@bind); |
25 | |
26 | # Just generate the WHERE clause |
abe72f94 |
27 | my($stmt, @bind) = $sql->where(\%where, \@order); |
32eab2da |
28 | |
29 | # Return values in the same order, for hashed queries |
30 | # See PERFORMANCE section for more details |
31 | my @bind = $sql->values(\%fieldvals); |
32 | |
33 | =head1 DESCRIPTION |
34 | |
35 | This module was inspired by the excellent L<DBIx::Abstract>. |
36 | However, in using that module I found that what I really wanted |
37 | to do was generate SQL, but still retain complete control over my |
38 | statement handles and use the DBI interface. So, I set out to |
39 | create an abstract SQL generation module. |
40 | |
41 | While based on the concepts used by L<DBIx::Abstract>, there are |
42 | several important differences, especially when it comes to WHERE |
43 | clauses. I have modified the concepts used to make the SQL easier |
44 | to generate from Perl data structures and, IMO, more intuitive. |
45 | The underlying idea is for this module to do what you mean, based |
46 | on the data structures you provide it. The big advantage is that |
47 | you don't have to modify your code every time your data changes, |
48 | as this module figures it out. |
49 | |
50 | To begin with, an SQL INSERT is as easy as just specifying a hash |
51 | of C<key=value> pairs: |
52 | |
53 | my %data = ( |
54 | name => 'Jimbo Bobson', |
55 | phone => '123-456-7890', |
56 | address => '42 Sister Lane', |
57 | city => 'St. Louis', |
58 | state => 'Louisiana', |
59 | ); |
60 | |
61 | The SQL can then be generated with this: |
62 | |
63 | my($stmt, @bind) = $sql->insert('people', \%data); |
64 | |
65 | Which would give you something like this: |
66 | |
67 | $stmt = "INSERT INTO people |
68 | (address, city, name, phone, state) |
69 | VALUES (?, ?, ?, ?, ?)"; |
70 | @bind = ('42 Sister Lane', 'St. Louis', 'Jimbo Bobson', |
71 | '123-456-7890', 'Louisiana'); |
72 | |
73 | These are then used directly in your DBI code: |
74 | |
75 | my $sth = $dbh->prepare($stmt); |
76 | $sth->execute(@bind); |
77 | |
78 | In addition, you can apply SQL functions to elements of your C<%data> |
79 | by specifying an arrayref for the given hash value. For example, if |
80 | you need to execute the Oracle C<to_date> function on a value, you |
81 | can say something like this: |
82 | |
83 | my %data = ( |
84 | name => 'Bill', |
85 | date_entered => ["to_date(?,'MM/DD/YYYY')", "03/02/2003"], |
86 | ); |
87 | |
88 | The first value in the array is the actual SQL. Any other values are |
89 | optional and would be included in the bind values array. This gives |
90 | you: |
91 | |
92 | my($stmt, @bind) = $sql->insert('people', \%data); |
93 | |
94 | $stmt = "INSERT INTO people (name, date_entered) |
95 | VALUES (?, to_date(?,'MM/DD/YYYY'))"; |
96 | @bind = ('Bill', '03/02/2003'); |
97 | |
98 | An UPDATE is just as easy, all you change is the name of the function: |
99 | |
100 | my($stmt, @bind) = $sql->update('people', \%data); |
101 | |
102 | Notice that your C<%data> isn't touched; the module will generate |
103 | the appropriately quirky SQL for you automatically. Usually you'll |
104 | want to specify a WHERE clause for your UPDATE, though, which is |
105 | where handling C<%where> hashes comes in handy... |
106 | |
107 | This module can generate pretty complicated WHERE statements |
108 | easily. For example, simple C<key=value> pairs are taken to mean |
109 | equality, and if you want to see if a field is within a set |
110 | of values, you can use an arrayref. Let's say we wanted to |
111 | SELECT some data based on this criteria: |
112 | |
113 | my %where = ( |
114 | requestor => 'inna', |
115 | worker => ['nwiger', 'rcwe', 'sfz'], |
116 | status => { '!=', 'completed' } |
117 | ); |
118 | |
119 | my($stmt, @bind) = $sql->select('tickets', '*', \%where); |
120 | |
121 | The above would give you something like this: |
122 | |
123 | $stmt = "SELECT * FROM tickets WHERE |
124 | ( requestor = ? ) AND ( status != ? ) |
125 | AND ( worker = ? OR worker = ? OR worker = ? )"; |
126 | @bind = ('inna', 'completed', 'nwiger', 'rcwe', 'sfz'); |
127 | |
128 | Which you could then use in DBI code like so: |
129 | |
130 | my $sth = $dbh->prepare($stmt); |
131 | $sth->execute(@bind); |
132 | |
133 | Easy, eh? |
134 | |
135 | =head1 FUNCTIONS |
136 | |
137 | The functions are simple. There's one for each major SQL operation, |
138 | and a constructor you use first. The arguments are specified in a |
139 | similar order to each function (table, then fields, then a where |
140 | clause) to try and simplify things. |
141 | |
142 | =cut |
143 | |
144 | use Carp; |
145 | use strict; |
146 | |
69f2a249 |
147 | our $VERSION = '1.22'; |
148 | our $REVISION = '$Id$'; |
32eab2da |
149 | our $AUTOLOAD; |
150 | |
151 | # Fix SQL case, if so requested |
152 | sub _sqlcase { |
153 | my $self = shift; |
154 | return $self->{case} ? $_[0] : uc($_[0]); |
155 | } |
156 | |
157 | # Anon copies of arrays/hashes |
158 | # Based on deep_copy example by merlyn |
159 | # http://www.stonehenge.com/merlyn/UnixReview/col30.html |
160 | sub _anoncopy { |
161 | my $orig = shift; |
162 | return (ref $orig eq 'HASH') ? +{map { $_ => _anoncopy($orig->{$_}) } keys %$orig} |
163 | : (ref $orig eq 'ARRAY') ? [map _anoncopy($_), @$orig] |
164 | : $orig; |
165 | } |
166 | |
167 | # Debug |
168 | sub _debug { |
169 | return unless $_[0]->{debug}; shift; # a little faster |
170 | my $func = (caller(1))[3]; |
171 | warn "[$func] ", @_, "\n"; |
172 | } |
173 | |
174 | sub belch (@) { |
175 | my($func) = (caller(1))[3]; |
176 | carp "[$func] Warning: ", @_; |
177 | } |
178 | |
179 | sub puke (@) { |
180 | my($func) = (caller(1))[3]; |
181 | croak "[$func] Fatal: ", @_; |
182 | } |
183 | |
184 | # Utility functions |
185 | sub _table { |
186 | my $self = shift; |
83cab70b |
187 | my $from = shift; |
188 | if (ref $from eq 'ARRAY') { |
189 | return $self->_recurse_from(@$from); |
190 | } elsif (ref $from eq 'HASH') { |
191 | return $self->_make_as($from); |
32eab2da |
192 | } else { |
83cab70b |
193 | return $self->_quote($from); |
32eab2da |
194 | } |
195 | } |
196 | |
83cab70b |
197 | sub _recurse_from { |
198 | my ($self, $from, @join) = @_; |
199 | my @sqlf; |
200 | push(@sqlf, $self->_make_as($from)); |
201 | foreach my $j (@join) { |
202 | push @sqlf, ', ' . $self->_quote($j) and next unless ref $j; |
203 | push @sqlf, ', ' . $$j and next if ref $j eq 'SCALAR'; |
204 | my ($to, $on) = @$j; |
205 | |
206 | # check whether a join type exists |
207 | my $join_clause = ''; |
208 | my $to_jt = ref($to) eq 'ARRAY' ? $to->[0] : $to; |
209 | if (ref($to_jt) eq 'HASH' and exists($to_jt->{-join_type})) { |
210 | $join_clause = $self->_sqlcase(' '.($to_jt->{-join_type}).' JOIN '); |
211 | } else { |
212 | $join_clause = $self->_sqlcase(' JOIN '); |
213 | } |
214 | push(@sqlf, $join_clause); |
215 | |
216 | if (ref $to eq 'ARRAY') { |
217 | push(@sqlf, '(', $self->_recurse_from(@$to), ')'); |
218 | } else { |
219 | push(@sqlf, $self->_make_as($to)); |
220 | } |
221 | push(@sqlf, $self->_sqlcase(' ON '), $self->_join_condition($on)); |
222 | } |
223 | return join('', @sqlf); |
224 | } |
225 | |
226 | sub _make_as { |
227 | my ($self, $from) = @_; |
228 | return $self->_quote($from) unless ref $from; |
229 | return $$from if ref $from eq 'SCALAR'; |
230 | return join(' ', map { (ref $_ eq 'SCALAR' ? $$_ : $self->_quote($_)) } |
231 | reverse each %{$self->_skip_options($from)}); |
232 | } |
233 | |
234 | sub _skip_options { |
235 | my ($self, $hash) = @_; |
236 | my $clean_hash = {}; |
237 | $clean_hash->{$_} = $hash->{$_} |
238 | for grep {!/^-/} keys %$hash; |
239 | return $clean_hash; |
240 | } |
241 | |
242 | sub _join_condition { |
243 | my ($self, $cond) = @_; |
244 | if (ref $cond eq 'HASH') { |
245 | my %j; |
246 | for (keys %$cond) { |
247 | my $x = '= '.$self->_quote($cond->{$_}); $j{$_} = \$x; |
248 | }; |
249 | return $self->_recurse_where(\%j); |
250 | } elsif (ref $cond eq 'ARRAY') { |
251 | return join(' OR ', map { $self->_join_condition($_) } @$cond); |
252 | } else { |
253 | die "Can't handle this yet!"; |
254 | } |
255 | } |
256 | |
257 | |
32eab2da |
258 | sub _quote { |
259 | my $self = shift; |
260 | my $label = shift; |
261 | |
83cab70b |
262 | return '' unless defined $label; |
263 | |
32eab2da |
264 | return $label |
265 | if $label eq '*'; |
266 | |
83cab70b |
267 | return $label unless $self->{quote_char}; |
268 | |
269 | if (ref $self->{quote_char} eq "ARRAY") { |
270 | |
271 | return $self->{quote_char}->[0] . $label . $self->{quote_char}->[1] |
272 | if !defined $self->{name_sep}; |
273 | |
274 | my $sep = $self->{name_sep}; |
275 | return join($self->{name_sep}, |
276 | map { $self->{quote_char}->[0] . $_ . $self->{quote_char}->[1] } |
277 | split( /\Q$sep\E/, $label ) ); |
278 | } |
279 | |
280 | |
32eab2da |
281 | return $self->{quote_char} . $label . $self->{quote_char} |
282 | if !defined $self->{name_sep}; |
283 | |
284 | return join $self->{name_sep}, |
285 | map { $self->{quote_char} . $_ . $self->{quote_char} } |
286 | split /\Q$self->{name_sep}\E/, $label; |
287 | } |
288 | |
289 | # Conversion, if applicable |
290 | sub _convert ($) { |
291 | my $self = shift; |
292 | return @_ unless $self->{convert}; |
293 | my $conv = $self->_sqlcase($self->{convert}); |
294 | my @ret = map { $conv.'('.$_.')' } @_; |
295 | return wantarray ? @ret : $ret[0]; |
296 | } |
297 | |
298 | # And bindtype |
299 | sub _bindtype (@) { |
300 | my $self = shift; |
301 | my($col,@val) = @_; |
302 | return $self->{bindtype} eq 'columns' ? [ @_ ] : @val; |
303 | } |
304 | |
305 | # Modified -logic or -nest |
306 | sub _modlogic ($) { |
307 | my $self = shift; |
308 | my $sym = @_ ? lc(shift) : $self->{logic}; |
309 | $sym =~ tr/_/ /; |
310 | $sym = $self->{logic} if $sym eq 'nest'; |
311 | return $self->_sqlcase($sym); # override join |
312 | } |
313 | |
314 | =head2 new(option => 'value') |
315 | |
316 | The C<new()> function takes a list of options and values, and returns |
317 | a new B<SQL::Abstract> object which can then be used to generate SQL |
318 | through the methods below. The options accepted are: |
319 | |
320 | =over |
321 | |
322 | =item case |
323 | |
324 | If set to 'lower', then SQL will be generated in all lowercase. By |
325 | default SQL is generated in "textbook" case meaning something like: |
326 | |
327 | SELECT a_field FROM a_table WHERE some_field LIKE '%someval%' |
328 | |
329 | =item cmp |
330 | |
331 | This determines what the default comparison operator is. By default |
332 | it is C<=>, meaning that a hash like this: |
333 | |
334 | %where = (name => 'nwiger', email => 'nate@wiger.org'); |
335 | |
336 | Will generate SQL like this: |
337 | |
338 | WHERE name = 'nwiger' AND email = 'nate@wiger.org' |
339 | |
340 | However, you may want loose comparisons by default, so if you set |
341 | C<cmp> to C<like> you would get SQL such as: |
342 | |
343 | WHERE name like 'nwiger' AND email like 'nate@wiger.org' |
344 | |
345 | You can also override the comparsion on an individual basis - see |
346 | the huge section on L</"WHERE CLAUSES"> at the bottom. |
347 | |
348 | =item logic |
349 | |
350 | This determines the default logical operator for multiple WHERE |
351 | statements in arrays. By default it is "or", meaning that a WHERE |
352 | array of the form: |
353 | |
354 | @where = ( |
355 | event_date => {'>=', '2/13/99'}, |
356 | event_date => {'<=', '4/24/03'}, |
357 | ); |
358 | |
359 | Will generate SQL like this: |
360 | |
361 | WHERE event_date >= '2/13/99' OR event_date <= '4/24/03' |
362 | |
363 | This is probably not what you want given this query, though (look |
364 | at the dates). To change the "OR" to an "AND", simply specify: |
365 | |
366 | my $sql = SQL::Abstract->new(logic => 'and'); |
367 | |
368 | Which will change the above C<WHERE> to: |
369 | |
370 | WHERE event_date >= '2/13/99' AND event_date <= '4/24/03' |
371 | |
372 | =item convert |
373 | |
374 | This will automatically convert comparisons using the specified SQL |
375 | function for both column and value. This is mostly used with an argument |
376 | of C<upper> or C<lower>, so that the SQL will have the effect of |
377 | case-insensitive "searches". For example, this: |
378 | |
379 | $sql = SQL::Abstract->new(convert => 'upper'); |
380 | %where = (keywords => 'MaKe iT CAse inSeNSItive'); |
381 | |
382 | Will turn out the following SQL: |
383 | |
384 | WHERE upper(keywords) like upper('MaKe iT CAse inSeNSItive') |
385 | |
386 | The conversion can be C<upper()>, C<lower()>, or any other SQL function |
387 | that can be applied symmetrically to fields (actually B<SQL::Abstract> does |
388 | not validate this option; it will just pass through what you specify verbatim). |
389 | |
390 | =item bindtype |
391 | |
392 | This is a kludge because many databases suck. For example, you can't |
393 | just bind values using DBI's C<execute()> for Oracle C<CLOB> or C<BLOB> fields. |
394 | Instead, you have to use C<bind_param()>: |
395 | |
396 | $sth->bind_param(1, 'reg data'); |
397 | $sth->bind_param(2, $lots, {ora_type => ORA_CLOB}); |
398 | |
399 | The problem is, B<SQL::Abstract> will normally just return a C<@bind> array, |
400 | which loses track of which field each slot refers to. Fear not. |
401 | |
402 | If you specify C<bindtype> in new, you can determine how C<@bind> is returned. |
403 | Currently, you can specify either C<normal> (default) or C<columns>. If you |
404 | specify C<columns>, you will get an array that looks like this: |
405 | |
406 | my $sql = SQL::Abstract->new(bindtype => 'columns'); |
407 | my($stmt, @bind) = $sql->insert(...); |
408 | |
409 | @bind = ( |
410 | [ 'column1', 'value1' ], |
411 | [ 'column2', 'value2' ], |
412 | [ 'column3', 'value3' ], |
413 | ); |
414 | |
415 | You can then iterate through this manually, using DBI's C<bind_param()>. |
416 | |
417 | $sth->prepare($stmt); |
418 | my $i = 1; |
419 | for (@bind) { |
420 | my($col, $data) = @$_; |
421 | if ($col eq 'details' || $col eq 'comments') { |
422 | $sth->bind_param($i, $data, {ora_type => ORA_CLOB}); |
423 | } elsif ($col eq 'image') { |
424 | $sth->bind_param($i, $data, {ora_type => ORA_BLOB}); |
425 | } else { |
426 | $sth->bind_param($i, $data); |
427 | } |
428 | $i++; |
429 | } |
430 | $sth->execute; # execute without @bind now |
431 | |
432 | Now, why would you still use B<SQL::Abstract> if you have to do this crap? |
433 | Basically, the advantage is still that you don't have to care which fields |
434 | are or are not included. You could wrap that above C<for> loop in a simple |
435 | sub called C<bind_fields()> or something and reuse it repeatedly. You still |
436 | get a layer of abstraction over manual SQL specification. |
437 | |
438 | =item quote_char |
439 | |
440 | This is the character that a table or column name will be quoted |
441 | with. By default this is an empty string, but you could set it to |
442 | the character C<`>, to generate SQL like this: |
443 | |
444 | SELECT `a_field` FROM `a_table` WHERE `some_field` LIKE '%someval%' |
445 | |
446 | This is useful if you have tables or columns that are reserved words |
447 | in your database's SQL dialect. |
448 | |
449 | =item name_sep |
450 | |
451 | This is the character that separates a table and column name. It is |
452 | necessary to specify this when the C<quote_char> option is selected, |
453 | so that tables and column names can be individually quoted like this: |
454 | |
455 | SELECT `table`.`one_field` FROM `table` WHERE `table`.`other_field` = 1 |
456 | |
457 | =back |
458 | |
459 | =cut |
460 | |
461 | sub new { |
462 | my $self = shift; |
463 | my $class = ref($self) || $self; |
464 | my %opt = (ref $_[0] eq 'HASH') ? %{$_[0]} : @_; |
465 | |
466 | # choose our case by keeping an option around |
467 | delete $opt{case} if $opt{case} && $opt{case} ne 'lower'; |
468 | |
469 | # override logical operator |
470 | $opt{logic} = uc $opt{logic} if $opt{logic}; |
471 | |
472 | # how to return bind vars |
473 | $opt{bindtype} ||= delete($opt{bind_type}) || 'normal'; |
474 | |
475 | # default comparison is "=", but can be overridden |
476 | $opt{cmp} ||= '='; |
477 | |
478 | # default quotation character around tables/columns |
479 | $opt{quote_char} ||= ''; |
480 | |
481 | return bless \%opt, $class; |
482 | } |
483 | |
484 | =head2 insert($table, \@values || \%fieldvals) |
485 | |
486 | This is the simplest function. You simply give it a table name |
487 | and either an arrayref of values or hashref of field/value pairs. |
488 | It returns an SQL INSERT statement and a list of bind values. |
489 | |
490 | =cut |
491 | |
492 | sub insert { |
493 | my $self = shift; |
494 | my $table = $self->_table(shift); |
495 | my $data = shift || return; |
496 | |
497 | my $sql = $self->_sqlcase('insert into') . " $table "; |
498 | my(@sqlf, @sqlv, @sqlq) = (); |
499 | |
500 | my $ref = ref $data; |
501 | if ($ref eq 'HASH') { |
502 | for my $k (sort keys %$data) { |
503 | my $v = $data->{$k}; |
504 | my $r = ref $v; |
505 | # named fields, so must save names in order |
506 | push @sqlf, $self->_quote($k); |
507 | if ($r eq 'ARRAY') { |
508 | # SQL included for values |
509 | my @val = @$v; |
510 | push @sqlq, shift @val; |
511 | push @sqlv, $self->_bindtype($k, @val); |
512 | } elsif ($r eq 'SCALAR') { |
513 | # embedded literal SQL |
514 | push @sqlq, $$v; |
515 | } else { |
516 | push @sqlq, '?'; |
517 | push @sqlv, $self->_bindtype($k, $v); |
518 | } |
519 | } |
520 | $sql .= '(' . join(', ', @sqlf) .') '. $self->_sqlcase('values') . ' ('. join(', ', @sqlq) .')'; |
521 | } elsif ($ref eq 'ARRAY') { |
522 | # just generate values(?,?) part |
523 | # no names (arrayref) so can't generate bindtype |
524 | carp "Warning: ",__PACKAGE__,"->insert called with arrayref when bindtype set" |
525 | if $self->{bindtype} ne 'normal'; |
526 | for my $v (@$data) { |
527 | my $r = ref $v; |
528 | if ($r eq 'ARRAY') { |
529 | my @val = @$v; |
530 | push @sqlq, shift @val; |
531 | push @sqlv, @val; |
532 | } elsif ($r eq 'SCALAR') { |
533 | # embedded literal SQL |
534 | push @sqlq, $$v; |
535 | } else { |
536 | push @sqlq, '?'; |
537 | push @sqlv, $v; |
538 | } |
539 | } |
540 | $sql .= $self->_sqlcase('values') . ' ('. join(', ', @sqlq) .')'; |
541 | } elsif ($ref eq 'SCALAR') { |
542 | # literal SQL |
543 | $sql .= $$data; |
544 | } else { |
545 | puke "Unsupported data type specified to \$sql->insert"; |
546 | } |
547 | |
548 | return wantarray ? ($sql, @sqlv) : $sql; |
549 | } |
550 | |
551 | =head2 update($table, \%fieldvals, \%where) |
552 | |
553 | This takes a table, hashref of field/value pairs, and an optional |
554 | hashref WHERE clause. It returns an SQL UPDATE function and a list |
555 | of bind values. |
556 | |
557 | =cut |
558 | |
559 | sub update { |
560 | my $self = shift; |
561 | my $table = $self->_table(shift); |
562 | my $data = shift || return; |
563 | my $where = shift; |
564 | |
565 | my $sql = $self->_sqlcase('update') . " $table " . $self->_sqlcase('set '); |
566 | my(@sqlf, @sqlv) = (); |
567 | |
568 | puke "Unsupported data type specified to \$sql->update" |
569 | unless ref $data eq 'HASH'; |
570 | |
571 | for my $k (sort keys %$data) { |
572 | my $v = $data->{$k}; |
573 | my $r = ref $v; |
574 | my $label = $self->_quote($k); |
575 | if ($r eq 'ARRAY') { |
576 | # SQL included for values |
577 | my @bind = @$v; |
578 | my $sql = shift @bind; |
579 | push @sqlf, "$label = $sql"; |
580 | push @sqlv, $self->_bindtype($k, @bind); |
581 | } elsif ($r eq 'SCALAR') { |
582 | # embedded literal SQL |
583 | push @sqlf, "$label = $$v"; |
584 | } else { |
585 | push @sqlf, "$label = ?"; |
586 | push @sqlv, $self->_bindtype($k, $v); |
587 | } |
588 | } |
589 | |
590 | $sql .= join ', ', @sqlf; |
591 | |
592 | if ($where) { |
593 | my($wsql, @wval) = $self->where($where); |
594 | $sql .= $wsql; |
595 | push @sqlv, @wval; |
596 | } |
597 | |
598 | return wantarray ? ($sql, @sqlv) : $sql; |
599 | } |
600 | |
601 | =head2 select($table, \@fields, \%where, \@order) |
602 | |
603 | This takes a table, arrayref of fields (or '*'), optional hashref |
604 | WHERE clause, and optional arrayref order by, and returns the |
605 | corresponding SQL SELECT statement and list of bind values. |
606 | |
607 | =cut |
608 | |
609 | sub select { |
610 | my $self = shift; |
611 | my $table = $self->_table(shift); |
612 | my $fields = shift || '*'; |
613 | my $where = shift; |
614 | my $order = shift; |
615 | |
616 | my $f = (ref $fields eq 'ARRAY') ? join ', ', map { $self->_quote($_) } @$fields : $fields; |
617 | my $sql = join ' ', $self->_sqlcase('select'), $f, $self->_sqlcase('from'), $table; |
618 | |
619 | my(@sqlf, @sqlv) = (); |
620 | my($wsql, @wval) = $self->where($where, $order); |
621 | $sql .= $wsql; |
622 | push @sqlv, @wval; |
623 | |
624 | return wantarray ? ($sql, @sqlv) : $sql; |
625 | } |
626 | |
627 | =head2 delete($table, \%where) |
628 | |
629 | This takes a table name and optional hashref WHERE clause. |
630 | It returns an SQL DELETE statement and list of bind values. |
631 | |
632 | =cut |
633 | |
634 | sub delete { |
635 | my $self = shift; |
636 | my $table = $self->_table(shift); |
637 | my $where = shift; |
638 | |
639 | my $sql = $self->_sqlcase('delete from') . " $table"; |
640 | my(@sqlf, @sqlv) = (); |
641 | |
642 | if ($where) { |
643 | my($wsql, @wval) = $self->where($where); |
644 | $sql .= $wsql; |
645 | push @sqlv, @wval; |
646 | } |
647 | |
648 | return wantarray ? ($sql, @sqlv) : $sql; |
649 | } |
650 | |
651 | =head2 where(\%where, \@order) |
652 | |
653 | This is used to generate just the WHERE clause. For example, |
654 | if you have an arbitrary data structure and know what the |
655 | rest of your SQL is going to look like, but want an easy way |
656 | to produce a WHERE clause, use this. It returns an SQL WHERE |
657 | clause and list of bind values. |
658 | |
659 | =cut |
660 | |
661 | # Finally, a separate routine just to handle WHERE clauses |
662 | sub where { |
663 | my $self = shift; |
664 | my $where = shift; |
665 | my $order = shift; |
666 | |
667 | # Need a separate routine to properly wrap w/ "where" |
668 | my $sql = ''; |
669 | my @ret = $self->_recurse_where($where); |
670 | if (@ret) { |
671 | my $wh = shift @ret; |
672 | $sql .= $self->_sqlcase(' where ') . $wh if $wh; |
673 | } |
674 | |
675 | # order by? |
676 | if ($order) { |
677 | $sql .= $self->_order_by($order); |
678 | } |
679 | |
680 | return wantarray ? ($sql, @ret) : $sql; |
681 | } |
682 | |
683 | |
684 | sub _recurse_where { |
685 | local $^W = 0; # really, you've gotta be fucking kidding me |
686 | my $self = shift; |
687 | my $where = _anoncopy(shift); # prevent destroying original |
688 | my $ref = ref $where || ''; |
689 | my $join = shift || $self->{logic} || |
690 | ($ref eq 'ARRAY' ? $self->_sqlcase('or') : $self->_sqlcase('and')); |
691 | |
692 | # For assembling SQL fields and values |
693 | my(@sqlf, @sqlv) = (); |
694 | |
695 | # If an arrayref, then we join each element |
696 | if ($ref eq 'ARRAY') { |
697 | # need to use while() so can shift() for arrays |
698 | my $subjoin; |
699 | while (my $el = shift @$where) { |
700 | |
701 | # skip empty elements, otherwise get invalid trailing AND stuff |
702 | if (my $ref2 = ref $el) { |
703 | if ($ref2 eq 'ARRAY') { |
704 | next unless @$el; |
705 | } elsif ($ref2 eq 'HASH') { |
706 | next unless %$el; |
707 | $subjoin ||= $self->_sqlcase('and'); |
708 | } elsif ($ref2 eq 'SCALAR') { |
709 | # literal SQL |
710 | push @sqlf, $$el; |
711 | next; |
712 | } |
713 | $self->_debug("$ref2(*top) means join with $subjoin"); |
714 | } else { |
715 | # top-level arrayref with scalars, recurse in pairs |
716 | $self->_debug("NOREF(*top) means join with $subjoin"); |
717 | $el = {$el => shift(@$where)}; |
718 | } |
719 | my @ret = $self->_recurse_where($el, $subjoin); |
720 | push @sqlf, shift @ret; |
721 | push @sqlv, @ret; |
722 | } |
723 | } |
724 | elsif ($ref eq 'HASH') { |
725 | # Note: during recursion, the last element will always be a hashref, |
726 | # since it needs to point a column => value. So this be the end. |
727 | for my $k (sort keys %$where) { |
728 | my $v = $where->{$k}; |
729 | my $label = $self->_quote($k); |
61fdf29c |
730 | |
32eab2da |
731 | if ($k =~ /^-(\D+)/) { |
732 | # special nesting, like -and, -or, -nest, so shift over |
733 | my $subjoin = $self->_modlogic($1); |
734 | $self->_debug("OP(-$1) means special logic ($subjoin), recursing..."); |
735 | my @ret = $self->_recurse_where($v, $subjoin); |
736 | push @sqlf, shift @ret; |
737 | push @sqlv, @ret; |
738 | } elsif (! defined($v)) { |
739 | # undef = null |
740 | $self->_debug("UNDEF($k) means IS NULL"); |
741 | push @sqlf, $label . $self->_sqlcase(' is null'); |
742 | } elsif (ref $v eq 'ARRAY') { |
743 | my @v = @$v; |
744 | |
745 | # multiple elements: multiple options |
746 | $self->_debug("ARRAY($k) means multiple elements: [ @v ]"); |
747 | |
748 | # special nesting, like -and, -or, -nest, so shift over |
749 | my $subjoin = $self->_sqlcase('or'); |
750 | if ($v[0] =~ /^-(\D+)/) { |
751 | $subjoin = $self->_modlogic($1); # override subjoin |
752 | $self->_debug("OP(-$1) means special logic ($subjoin), shifting..."); |
753 | shift @v; |
754 | } |
755 | |
756 | # map into an array of hashrefs and recurse |
757 | my @ret = $self->_recurse_where([map { {$k => $_} } @v], $subjoin); |
758 | |
759 | # push results into our structure |
760 | push @sqlf, shift @ret; |
761 | push @sqlv, @ret; |
762 | } elsif (ref $v eq 'HASH') { |
763 | # modified operator { '!=', 'completed' } |
764 | for my $f (sort keys %$v) { |
765 | my $x = $v->{$f}; |
61fdf29c |
766 | |
767 | # do the right thing for single -in values |
768 | $x = [$x] if ($f =~ /^-?\s*(not[\s_]+)?in\s*$/i && ref $x ne 'ARRAY'); |
769 | |
32eab2da |
770 | $self->_debug("HASH($k) means modified operator: { $f }"); |
771 | |
772 | # check for the operator being "IN" or "BETWEEN" or whatever |
773 | if (ref $x eq 'ARRAY') { |
774 | if ($f =~ /^-?\s*(not[\s_]+)?(in|between)\s*$/i) { |
775 | my $u = $self->_modlogic($1 . $2); |
776 | $self->_debug("HASH($f => $x) uses special operator: [ $u ]"); |
777 | if ($u =~ /between/i) { |
778 | # SQL sucks |
61fdf29c |
779 | # Throw an exception if you try to use between with |
780 | # anything other than 2 values |
781 | $self->puke("You need two values to use between") unless @$x == 2; |
32eab2da |
782 | push @sqlf, join ' ', $self->_convert($label), $u, $self->_convert('?'), |
783 | $self->_sqlcase('and'), $self->_convert('?'); |
61fdf29c |
784 | } elsif (@$x) { |
785 | # DWIM for empty arrayrefs |
32eab2da |
786 | push @sqlf, join ' ', $self->_convert($label), $u, '(', |
787 | join(', ', map { $self->_convert('?') } @$x), |
788 | ')'; |
61fdf29c |
789 | } elsif(@$x == 0){ |
790 | # Empty IN defaults to 0=1 and empty NOT IN to 1=1 |
791 | push(@sqlf, ($u =~ /not/i ? "1=1" : "0=1")); |
32eab2da |
792 | } |
793 | push @sqlv, $self->_bindtype($k, @$x); |
794 | } else { |
795 | # multiple elements: multiple options |
796 | $self->_debug("ARRAY($x) means multiple elements: [ @$x ]"); |
797 | |
798 | # map into an array of hashrefs and recurse |
799 | my @ret = $self->_recurse_where([map { {$k => {$f, $_}} } @$x]); |
800 | |
801 | # push results into our structure |
802 | push @sqlf, shift @ret; |
803 | push @sqlv, @ret; |
804 | } |
805 | } elsif (! defined($x)) { |
806 | # undef = NOT null |
807 | my $not = ($f eq '!=' || $f eq 'not like') ? ' not' : ''; |
808 | push @sqlf, $label . $self->_sqlcase(" is$not null"); |
809 | } else { |
810 | # regular ol' value |
811 | $f =~ s/^-//; # strip leading -like => |
812 | $f =~ s/_/ /; # _ => " " |
813 | push @sqlf, join ' ', $self->_convert($label), $self->_sqlcase($f), $self->_convert('?'); |
814 | push @sqlv, $self->_bindtype($k, $x); |
815 | } |
816 | } |
817 | } elsif (ref $v eq 'SCALAR') { |
818 | # literal SQL |
819 | $self->_debug("SCALAR($k) means literal SQL: $$v"); |
820 | push @sqlf, "$label $$v"; |
821 | } else { |
822 | # standard key => val |
823 | $self->_debug("NOREF($k) means simple key=val: $k $self->{cmp} $v"); |
824 | push @sqlf, join ' ', $self->_convert($label), $self->_sqlcase($self->{cmp}), $self->_convert('?'); |
825 | push @sqlv, $self->_bindtype($k, $v); |
826 | } |
827 | } |
828 | } |
829 | elsif ($ref eq 'SCALAR') { |
830 | # literal sql |
831 | $self->_debug("SCALAR(*top) means literal SQL: $$where"); |
832 | push @sqlf, $$where; |
833 | } |
834 | elsif (defined $where) { |
835 | # literal sql |
836 | $self->_debug("NOREF(*top) means literal SQL: $where"); |
837 | push @sqlf, $where; |
838 | } |
839 | |
840 | # assemble and return sql |
841 | my $wsql = @sqlf ? '( ' . join(" $join ", @sqlf) . ' )' : ''; |
842 | return wantarray ? ($wsql, @sqlv) : $wsql; |
843 | } |
844 | |
845 | sub _order_by { |
846 | my $self = shift; |
847 | my $ref = ref $_[0]; |
848 | |
849 | my @vals = $ref eq 'ARRAY' ? @{$_[0]} : |
850 | $ref eq 'SCALAR' ? ${$_[0]} : |
851 | $ref eq '' ? $_[0] : |
852 | puke "Unsupported data struct $ref for ORDER BY"; |
853 | |
854 | my $val = join ', ', map { $self->_quote($_) } @vals; |
855 | return $val ? $self->_sqlcase(' order by')." $val" : ''; |
856 | } |
857 | |
858 | =head2 values(\%data) |
859 | |
860 | This just returns the values from the hash C<%data>, in the same |
861 | order that would be returned from any of the other above queries. |
862 | Using this allows you to markedly speed up your queries if you |
863 | are affecting lots of rows. See below under the L</"PERFORMANCE"> section. |
864 | |
865 | =cut |
866 | |
867 | sub values { |
868 | my $self = shift; |
869 | my $data = shift || return; |
870 | puke "Argument to ", __PACKAGE__, "->values must be a \\%hash" |
871 | unless ref $data eq 'HASH'; |
872 | return map { $self->_bindtype($_, $data->{$_}) } sort keys %$data; |
873 | } |
874 | |
875 | =head2 generate($any, 'number', $of, \@data, $struct, \%types) |
876 | |
877 | Warning: This is an experimental method and subject to change. |
878 | |
879 | This returns arbitrarily generated SQL. It's a really basic shortcut. |
880 | It will return two different things, depending on return context: |
881 | |
882 | my($stmt, @bind) = $sql->generate('create table', \$table, \@fields); |
883 | my $stmt_and_val = $sql->generate('create table', \$table, \@fields); |
884 | |
885 | These would return the following: |
886 | |
887 | # First calling form |
888 | $stmt = "CREATE TABLE test (?, ?)"; |
889 | @bind = (field1, field2); |
890 | |
891 | # Second calling form |
892 | $stmt_and_val = "CREATE TABLE test (field1, field2)"; |
893 | |
894 | Depending on what you're trying to do, it's up to you to choose the correct |
895 | format. In this example, the second form is what you would want. |
896 | |
897 | By the same token: |
898 | |
899 | $sql->generate('alter session', { nls_date_format => 'MM/YY' }); |
900 | |
901 | Might give you: |
902 | |
903 | ALTER SESSION SET nls_date_format = 'MM/YY' |
904 | |
905 | You get the idea. Strings get their case twiddled, but everything |
906 | else remains verbatim. |
907 | |
908 | =cut |
909 | |
910 | sub generate { |
911 | my $self = shift; |
912 | |
913 | my(@sql, @sqlq, @sqlv); |
914 | |
915 | for (@_) { |
916 | my $ref = ref $_; |
917 | if ($ref eq 'HASH') { |
918 | for my $k (sort keys %$_) { |
919 | my $v = $_->{$k}; |
920 | my $r = ref $v; |
921 | my $label = $self->_quote($k); |
922 | if ($r eq 'ARRAY') { |
923 | # SQL included for values |
924 | my @bind = @$v; |
925 | my $sql = shift @bind; |
926 | push @sqlq, "$label = $sql"; |
927 | push @sqlv, $self->_bindtype($k, @bind); |
928 | } elsif ($r eq 'SCALAR') { |
929 | # embedded literal SQL |
930 | push @sqlq, "$label = $$v"; |
931 | } else { |
932 | push @sqlq, "$label = ?"; |
933 | push @sqlv, $self->_bindtype($k, $v); |
934 | } |
935 | } |
936 | push @sql, $self->_sqlcase('set'), join ', ', @sqlq; |
937 | } elsif ($ref eq 'ARRAY') { |
938 | # unlike insert(), assume these are ONLY the column names, i.e. for SQL |
939 | for my $v (@$_) { |
940 | my $r = ref $v; |
941 | if ($r eq 'ARRAY') { |
942 | my @val = @$v; |
943 | push @sqlq, shift @val; |
944 | push @sqlv, @val; |
945 | } elsif ($r eq 'SCALAR') { |
946 | # embedded literal SQL |
947 | push @sqlq, $$v; |
948 | } else { |
949 | push @sqlq, '?'; |
950 | push @sqlv, $v; |
951 | } |
952 | } |
953 | push @sql, '(' . join(', ', @sqlq) . ')'; |
954 | } elsif ($ref eq 'SCALAR') { |
955 | # literal SQL |
956 | push @sql, $$_; |
957 | } else { |
958 | # strings get case twiddled |
959 | push @sql, $self->_sqlcase($_); |
960 | } |
961 | } |
962 | |
963 | my $sql = join ' ', @sql; |
964 | |
965 | # this is pretty tricky |
966 | # if ask for an array, return ($stmt, @bind) |
967 | # otherwise, s/?/shift @sqlv/ to put it inline |
968 | if (wantarray) { |
969 | return ($sql, @sqlv); |
970 | } else { |
971 | 1 while $sql =~ s/\?/my $d = shift(@sqlv); |
972 | ref $d ? $d->[1] : $d/e; |
973 | return $sql; |
974 | } |
975 | } |
976 | |
977 | sub DESTROY { 1 } |
978 | sub AUTOLOAD { |
979 | # This allows us to check for a local, then _form, attr |
980 | my $self = shift; |
981 | my($name) = $AUTOLOAD =~ /.*::(.+)/; |
982 | return $self->generate($name, @_); |
983 | } |
984 | |
985 | 1; |
986 | |
987 | __END__ |
988 | |
989 | =head1 WHERE CLAUSES |
990 | |
991 | This module uses a variation on the idea from L<DBIx::Abstract>. It |
992 | is B<NOT>, repeat I<not> 100% compatible. B<The main logic of this |
993 | module is that things in arrays are OR'ed, and things in hashes |
994 | are AND'ed.> |
995 | |
996 | The easiest way to explain is to show lots of examples. After |
997 | each C<%where> hash shown, it is assumed you used: |
998 | |
999 | my($stmt, @bind) = $sql->where(\%where); |
1000 | |
1001 | However, note that the C<%where> hash can be used directly in any |
1002 | of the other functions as well, as described above. |
1003 | |
1004 | So, let's get started. To begin, a simple hash: |
1005 | |
1006 | my %where = ( |
1007 | user => 'nwiger', |
1008 | status => 'completed' |
1009 | ); |
1010 | |
1011 | Is converted to SQL C<key = val> statements: |
1012 | |
1013 | $stmt = "WHERE user = ? AND status = ?"; |
1014 | @bind = ('nwiger', 'completed'); |
1015 | |
1016 | One common thing I end up doing is having a list of values that |
1017 | a field can be in. To do this, simply specify a list inside of |
1018 | an arrayref: |
1019 | |
1020 | my %where = ( |
1021 | user => 'nwiger', |
1022 | status => ['assigned', 'in-progress', 'pending']; |
1023 | ); |
1024 | |
1025 | This simple code will create the following: |
1026 | |
1027 | $stmt = "WHERE user = ? AND ( status = ? OR status = ? OR status = ? )"; |
1028 | @bind = ('nwiger', 'assigned', 'in-progress', 'pending'); |
1029 | |
1030 | If you want to specify a different type of operator for your comparison, |
1031 | you can use a hashref for a given column: |
1032 | |
1033 | my %where = ( |
1034 | user => 'nwiger', |
1035 | status => { '!=', 'completed' } |
1036 | ); |
1037 | |
1038 | Which would generate: |
1039 | |
1040 | $stmt = "WHERE user = ? AND status != ?"; |
1041 | @bind = ('nwiger', 'completed'); |
1042 | |
1043 | To test against multiple values, just enclose the values in an arrayref: |
1044 | |
1045 | status => { '!=', ['assigned', 'in-progress', 'pending'] }; |
1046 | |
1047 | Which would give you: |
1048 | |
1049 | "WHERE status != ? OR status != ? OR status != ?" |
1050 | |
1051 | But, this is probably not what you want in this case (look at it). So |
1052 | the hashref can also contain multiple pairs, in which case it is expanded |
1053 | into an C<AND> of its elements: |
1054 | |
1055 | my %where = ( |
1056 | user => 'nwiger', |
1057 | status => { '!=', 'completed', -not_like => 'pending%' } |
1058 | ); |
1059 | |
1060 | # Or more dynamically, like from a form |
1061 | $where{user} = 'nwiger'; |
1062 | $where{status}{'!='} = 'completed'; |
1063 | $where{status}{'-not_like'} = 'pending%'; |
1064 | |
1065 | # Both generate this |
1066 | $stmt = "WHERE user = ? AND status != ? AND status NOT LIKE ?"; |
1067 | @bind = ('nwiger', 'completed', 'pending%'); |
1068 | |
1069 | To get an OR instead, you can combine it with the arrayref idea: |
1070 | |
1071 | my %where => ( |
1072 | user => 'nwiger', |
1073 | priority => [ {'=', 2}, {'!=', 1} ] |
1074 | ); |
1075 | |
1076 | Which would generate: |
1077 | |
1078 | $stmt = "WHERE user = ? AND priority = ? OR priority != ?"; |
1079 | @bind = ('nwiger', '2', '1'); |
1080 | |
1081 | However, there is a subtle trap if you want to say something like |
1082 | this (notice the C<AND>): |
1083 | |
1084 | WHERE priority != ? AND priority != ? |
1085 | |
1086 | Because, in Perl you I<can't> do this: |
1087 | |
1088 | priority => { '!=', 2, '!=', 1 } |
1089 | |
1090 | As the second C<!=> key will obliterate the first. The solution |
1091 | is to use the special C<-modifier> form inside an arrayref: |
1092 | |
1093 | priority => [ -and => {'!=', 2}, {'!=', 1} ] |
1094 | |
1095 | Normally, these would be joined by C<OR>, but the modifier tells it |
1096 | to use C<AND> instead. (Hint: You can use this in conjunction with the |
1097 | C<logic> option to C<new()> in order to change the way your queries |
1098 | work by default.) B<Important:> Note that the C<-modifier> goes |
1099 | B<INSIDE> the arrayref, as an extra first element. This will |
1100 | B<NOT> do what you think it might: |
1101 | |
1102 | priority => -and => [{'!=', 2}, {'!=', 1}] # WRONG! |
1103 | |
1104 | Here is a quick list of equivalencies, since there is some overlap: |
1105 | |
1106 | # Same |
1107 | status => {'!=', 'completed', 'not like', 'pending%' } |
1108 | status => [ -and => {'!=', 'completed'}, {'not like', 'pending%'}] |
1109 | |
1110 | # Same |
1111 | status => {'=', ['assigned', 'in-progress']} |
1112 | status => [ -or => {'=', 'assigned'}, {'=', 'in-progress'}] |
1113 | status => [ {'=', 'assigned'}, {'=', 'in-progress'} ] |
1114 | |
1115 | In addition to C<-and> and C<-or>, there is also a special C<-nest> |
1116 | operator which adds an additional set of parens, to create a subquery. |
1117 | For example, to get something like this: |
1118 | |
1119 | $stmt = WHERE user = ? AND ( workhrs > ? OR geo = ? ) |
1120 | @bind = ('nwiger', '20', 'ASIA'); |
1121 | |
1122 | You would do: |
1123 | |
1124 | my %where = ( |
1125 | user => 'nwiger', |
1126 | -nest => [ workhrs => {'>', 20}, geo => 'ASIA' ], |
1127 | ); |
1128 | |
1129 | You can also use the hashref format to compare a list of fields using the |
1130 | C<IN> comparison operator, by specifying the list as an arrayref: |
1131 | |
1132 | my %where = ( |
1133 | status => 'completed', |
1134 | reportid => { -in => [567, 2335, 2] } |
1135 | ); |
1136 | |
1137 | Which would generate: |
1138 | |
1139 | $stmt = "WHERE status = ? AND reportid IN (?,?,?)"; |
1140 | @bind = ('completed', '567', '2335', '2'); |
1141 | |
1142 | You can use this same format to use other grouping functions, such |
1143 | as C<BETWEEN>, C<SOME>, and so forth. For example: |
1144 | |
1145 | my %where = ( |
1146 | user => 'nwiger', |
1147 | completion_date => { |
1148 | -not_between => ['2002-10-01', '2003-02-06'] |
1149 | } |
1150 | ); |
1151 | |
1152 | Would give you: |
1153 | |
1154 | WHERE user = ? AND completion_date NOT BETWEEN ( ? AND ? ) |
1155 | |
1156 | So far, we've seen how multiple conditions are joined with a top-level |
1157 | C<AND>. We can change this by putting the different conditions we want in |
1158 | hashes and then putting those hashes in an array. For example: |
1159 | |
1160 | my @where = ( |
1161 | { |
1162 | user => 'nwiger', |
1163 | status => { -like => ['pending%', 'dispatched'] }, |
1164 | }, |
1165 | { |
1166 | user => 'robot', |
1167 | status => 'unassigned', |
1168 | } |
1169 | ); |
1170 | |
1171 | This data structure would create the following: |
1172 | |
1173 | $stmt = "WHERE ( user = ? AND ( status LIKE ? OR status LIKE ? ) ) |
1174 | OR ( user = ? AND status = ? ) )"; |
1175 | @bind = ('nwiger', 'pending', 'dispatched', 'robot', 'unassigned'); |
1176 | |
1177 | This can be combined with the C<-nest> operator to properly group |
1178 | SQL statements: |
1179 | |
1180 | my @where = ( |
1181 | -and => [ |
1182 | user => 'nwiger', |
1183 | -nest => [ |
1184 | -and => [workhrs => {'>', 20}, geo => 'ASIA' ], |
1185 | -and => [workhrs => {'<', 50}, geo => 'EURO' ] |
1186 | ], |
1187 | ], |
1188 | ); |
1189 | |
1190 | That would yield: |
1191 | |
1192 | WHERE ( user = ? AND |
1193 | ( ( workhrs > ? AND geo = ? ) |
1194 | OR ( workhrs < ? AND geo = ? ) ) ) |
1195 | |
1196 | Finally, sometimes only literal SQL will do. If you want to include |
1197 | literal SQL verbatim, you can specify it as a scalar reference, namely: |
1198 | |
1199 | my $inn = 'is Not Null'; |
1200 | my %where = ( |
1201 | priority => { '<', 2 }, |
1202 | requestor => \$inn |
1203 | ); |
1204 | |
1205 | This would create: |
1206 | |
1207 | $stmt = "WHERE priority < ? AND requestor is Not Null"; |
1208 | @bind = ('2'); |
1209 | |
1210 | Note that in this example, you only get one bind parameter back, since |
1211 | the verbatim SQL is passed as part of the statement. |
1212 | |
1213 | Of course, just to prove a point, the above can also be accomplished |
1214 | with this: |
1215 | |
1216 | my %where = ( |
1217 | priority => { '<', 2 }, |
1218 | requestor => { '!=', undef }, |
1219 | ); |
1220 | |
1221 | TMTOWTDI. |
1222 | |
1223 | These pages could go on for a while, since the nesting of the data |
1224 | structures this module can handle are pretty much unlimited (the |
1225 | module implements the C<WHERE> expansion as a recursive function |
1226 | internally). Your best bet is to "play around" with the module a |
1227 | little to see how the data structures behave, and choose the best |
1228 | format for your data based on that. |
1229 | |
1230 | And of course, all the values above will probably be replaced with |
1231 | variables gotten from forms or the command line. After all, if you |
1232 | knew everything ahead of time, you wouldn't have to worry about |
1233 | dynamically-generating SQL and could just hardwire it into your |
1234 | script. |
1235 | |
1236 | =head1 PERFORMANCE |
1237 | |
1238 | Thanks to some benchmarking by Mark Stosberg, it turns out that |
1239 | this module is many orders of magnitude faster than using C<DBIx::Abstract>. |
1240 | I must admit this wasn't an intentional design issue, but it's a |
1241 | byproduct of the fact that you get to control your C<DBI> handles |
1242 | yourself. |
1243 | |
1244 | To maximize performance, use a code snippet like the following: |
1245 | |
1246 | # prepare a statement handle using the first row |
1247 | # and then reuse it for the rest of the rows |
1248 | my($sth, $stmt); |
1249 | for my $href (@array_of_hashrefs) { |
1250 | $stmt ||= $sql->insert('table', $href); |
1251 | $sth ||= $dbh->prepare($stmt); |
1252 | $sth->execute($sql->values($href)); |
1253 | } |
1254 | |
1255 | The reason this works is because the keys in your C<$href> are sorted |
1256 | internally by B<SQL::Abstract>. Thus, as long as your data retains |
1257 | the same structure, you only have to generate the SQL the first time |
1258 | around. On subsequent queries, simply use the C<values> function provided |
1259 | by this module to return your values in the correct order. |
1260 | |
1261 | =head1 FORMBUILDER |
1262 | |
1263 | If you use my C<CGI::FormBuilder> module at all, you'll hopefully |
1264 | really like this part (I do, at least). Building up a complex query |
1265 | can be as simple as the following: |
1266 | |
1267 | #!/usr/bin/perl |
1268 | |
1269 | use CGI::FormBuilder; |
1270 | use SQL::Abstract; |
1271 | |
1272 | my $form = CGI::FormBuilder->new(...); |
1273 | my $sql = SQL::Abstract->new; |
1274 | |
1275 | if ($form->submitted) { |
1276 | my $field = $form->field; |
1277 | my $id = delete $field->{id}; |
1278 | my($stmt, @bind) = $sql->update('table', $field, {id => $id}); |
1279 | } |
1280 | |
1281 | Of course, you would still have to connect using C<DBI> to run the |
1282 | query, but the point is that if you make your form look like your |
1283 | table, the actual query script can be extremely simplistic. |
1284 | |
1285 | If you're B<REALLY> lazy (I am), check out C<HTML::QuickTable> for |
1286 | a fast interface to returning and formatting data. I frequently |
1287 | use these three modules together to write complex database query |
1288 | apps in under 50 lines. |
1289 | |
1290 | =head1 NOTES |
1291 | |
1292 | There is not (yet) any explicit support for SQL compound logic |
1293 | statements like "AND NOT". Instead, just do the de Morgan's |
1294 | law transformations yourself. For example, this: |
1295 | |
1296 | "lname LIKE '%son%' AND NOT ( age < 10 OR age > 20 )" |
1297 | |
1298 | Becomes: |
1299 | |
1300 | "lname LIKE '%son%' AND ( age >= 10 AND age <= 20 )" |
1301 | |
1302 | With the corresponding C<%where> hash: |
1303 | |
1304 | %where = ( |
1305 | lname => {like => '%son%'}, |
1306 | age => [-and => {'>=', 10}, {'<=', 20}], |
1307 | ); |
1308 | |
1309 | Again, remember that the C<-and> goes I<inside> the arrayref. |
1310 | |
1311 | =head1 ACKNOWLEDGEMENTS |
1312 | |
1313 | There are a number of individuals that have really helped out with |
1314 | this module. Unfortunately, most of them submitted bugs via CPAN |
1315 | so I have no idea who they are! But the people I do know are: |
1316 | |
1317 | Mark Stosberg (benchmarking) |
1318 | Chas Owens (initial "IN" operator support) |
1319 | Philip Collins (per-field SQL functions) |
1320 | Eric Kolve (hashref "AND" support) |
1321 | Mike Fragassi (enhancements to "BETWEEN" and "LIKE") |
1322 | Dan Kubb (support for "quote_char" and "name_sep") |
abe72f94 |
1323 | Matt Trout (DBIx::Class support) |
32eab2da |
1324 | |
1325 | Thanks! |
1326 | |
1327 | =head1 BUGS |
1328 | |
1329 | If found, please DO NOT submit anything via C<rt.cpan.org> - that |
1330 | just causes me a ton of work. Email me a patch (or script demonstrating |
abe72f94 |
1331 | the problem) to the below address, and include the VERSION you're using. |
32eab2da |
1332 | |
1333 | =head1 SEE ALSO |
1334 | |
1335 | L<DBIx::Abstract>, L<DBI|DBI>, L<CGI::FormBuilder>, L<HTML::QuickTable> |
1336 | |
32eab2da |
1337 | =head1 AUTHOR |
1338 | |
6be9cea3 |
1339 | Copyright (c) 2001-2006 Nathan Wiger <nwiger@cpan.org>. All Rights Reserved. |
32eab2da |
1340 | |
abe72f94 |
1341 | For support, your best bet is to try the C<DBIx::Class> users mailing list. |
1342 | While not an official support venue, C<DBIx::Class> makes heavy use of |
1343 | C<SQL::Abstract>, and as such list members there are very familiar with |
1344 | how to create queries. |
1345 | |
32eab2da |
1346 | This module is free software; you may copy this under the terms of |
1347 | the GNU General Public License, or the Artistic License, copies of |
1348 | which should have accompanied your Perl kit. |
1349 | |
1350 | =cut |
1351 | |