use List::Util 'first';
use namespace::clean;
-# FIXME
-# This dialect has not been ported to the subquery-realiasing code
-# that all other subquerying dialects are using. It is very possible
-# that this dialect is entirely unnecessary - it is currently only
-# used by ::Storage::DBI::ODBC::DB2_400_SQL which *should* be able to
-# just subclass ::Storage::DBI::DB2 and use the already rewritten
-# RowNumberOver. However nobody has access to this specific database
-# engine, thus keeping legacy code as-is
-# IF someone ever manages to test DB2-AS/400 with RNO, all the code
-# in this block should go on to meet its maker
-{
- sub _FetchFirst {
- my ( $self, $sql, $order, $rows, $offset ) = @_;
-
- my $last = $rows + $offset;
-
- my ( $order_by_up, $order_by_down ) = $self->_order_directions( $order );
-
- $sql = "
- SELECT * FROM (
- SELECT * FROM (
- $sql
- $order_by_up
- FETCH FIRST $last ROWS ONLY
- ) foo
- $order_by_down
- FETCH FIRST $rows ROWS ONLY
- ) bar
- $order_by_up
- ";
-
- return $sql;
- }
-
- sub _order_directions {
- my ( $self, $order ) = @_;
-
- return unless $order;
-
- my $ref = ref $order;
-
- my @order;
-
- CASE: {
- @order = @$order, last CASE if $ref eq 'ARRAY';
- @order = ( $order ), last CASE unless $ref;
- @order = ( $$order ), last CASE if $ref eq 'SCALAR';
- $self->throw_exception(__PACKAGE__ . ": Unsupported data struct $ref for ORDER BY");
- }
-
- my ( $order_by_up, $order_by_down );
-
- foreach my $spec ( @order )
- {
- my @spec = split ' ', $spec;
- $self->throw_exception("bad column order spec: $spec") if @spec > 2;
- push( @spec, 'ASC' ) unless @spec == 2;
- my ( $col, $up ) = @spec; # or maybe down
- $up = uc( $up );
- $self->throw_exception("bad direction: $up") unless $up =~ /^(?:ASC|DESC)$/;
- $order_by_up .= ", $col $up";
- my $down = $up eq 'ASC' ? 'DESC' : 'ASC';
- $order_by_down .= ", $col $down";
- }
-
- s/^,/ORDER BY/ for ( $order_by_up, $order_by_down );
-
- return $order_by_up, $order_by_down;
- }
+# constants are used not only here, but also in comparison tests
+sub __rows_bindtype () {
+ +{ sqlt_datatype => 'integer' }
+}
+sub __offset_bindtype () {
+ +{ sqlt_datatype => 'integer' }
+}
+sub __total_bindtype () {
+ +{ sqlt_datatype => 'integer' }
}
-### end-of-FIXME
=head1 NAME
Currently the provided dialects are:
-=cut
-
=head2 LimitOffset
SELECT ... LIMIT $limit OFFSET $offset
=cut
sub _LimitOffset {
- my ( $self, $sql, $order, $rows, $offset ) = @_;
- $sql .= $self->_order_by( $order ) . " LIMIT $rows";
- $sql .= " OFFSET $offset" if +$offset;
+ my ( $self, $sql, $rs_attrs, $rows, $offset ) = @_;
+ $sql .= $self->_parse_rs_attrs( $rs_attrs ) . " LIMIT ?";
+ push @{$self->{limit_bind}}, [ $self->__rows_bindtype => $rows ];
+ if ($offset) {
+ $sql .= " OFFSET ?";
+ push @{$self->{limit_bind}}, [ $self->__offset_bindtype => $offset ];
+ }
return $sql;
}
=cut
sub _LimitXY {
- my ( $self, $sql, $order, $rows, $offset ) = @_;
- $sql .= $self->_order_by( $order ) . " LIMIT ";
- $sql .= "$offset, " if +$offset;
- $sql .= $rows;
+ my ( $self, $sql, $rs_attrs, $rows, $offset ) = @_;
+ $sql .= $self->_parse_rs_attrs( $rs_attrs ) . " LIMIT ";
+ if ($offset) {
+ $sql .= '?, ';
+ push @{$self->{limit_bind}}, [ $self->__offset_bindtype => $offset ];
+ }
+ $sql .= '?';
+ push @{$self->{limit_bind}}, [ $self->__rows_bindtype => $rows ];
+
return $sql;
}
sub _RowNumberOver {
my ($self, $sql, $rs_attrs, $rows, $offset ) = @_;
- # mangle the input sql as we will be replacing the selector
- $sql =~ s/^ \s* SELECT \s+ .+? \s+ (?= \b FROM \b )//ix
- or $self->throw_exception("Unrecognizable SELECT: $sql");
-
# get selectors, and scan the order_by (if any)
- my ($in_sel, $out_sel, $alias_map, $extra_order_sel)
- = $self->_subqueried_limit_attrs ( $rs_attrs );
+ my ($stripped_sql, $in_sel, $out_sel, $alias_map, $extra_order_sel)
+ = $self->_subqueried_limit_attrs ( $sql, $rs_attrs );
# make up an order if none exists
my $requested_order = (delete $rs_attrs->{order_by}) || $self->_rno_default_order;
my $qalias = $self->_quote ($rs_attrs->{alias});
my $idx_name = $self->_quote ('rno__row__index');
- $sql = sprintf (<<EOS, $offset + 1, $offset + $rows, );
+ push @{$self->{limit_bind}}, [ $self->__offset_bindtype => $offset + 1], [ $self->__total_bindtype => $offset + $rows ];
+
+ return <<EOS;
SELECT $out_sel FROM (
SELECT $mid_sel, ROW_NUMBER() OVER( $rno_ord ) AS $idx_name FROM (
- SELECT $in_sel ${sql}${group_having}
+ SELECT $in_sel ${stripped_sql}${group_having}
) $qalias
-) $qalias WHERE $idx_name BETWEEN %u AND %u
+) $qalias WHERE $idx_name >= ? AND $idx_name <= ?
EOS
- return $sql;
}
# some databases are happy with OVER (), some need OVER (ORDER BY (SELECT (1)) )
return sprintf ('SELECT %s%s%s%s',
$offset
- ? sprintf ('SKIP %u ', $offset)
+ ? do {
+ push @{$self->{limit_bind}}, [ $self->__offset_bindtype => $offset];
+ 'SKIP ? '
+ }
: ''
,
- sprintf ('FIRST %u ', $rows),
+ do {
+ push @{$self->{limit_bind}}, [ $self->__rows_bindtype => $rows ];
+ 'FIRST ? '
+ },
$sql,
$self->_parse_rs_attrs ($rs_attrs),
);
or $self->throw_exception("Unrecognizable SELECT: $sql");
return sprintf ('SELECT %s%s%s%s',
- sprintf ('FIRST %u ', $rows),
+ do {
+ push @{$self->{limit_bind}}, [ $self->__rows_bindtype => $rows ];
+ 'FIRST ? '
+ },
$offset
- ? sprintf ('SKIP %u ', $offset)
+ ? do {
+ push @{$self->{limit_bind}}, [ $self->__offset_bindtype => $offset];
+ 'SKIP ? '
+ }
: ''
,
$sql,
sub _RowNum {
my ( $self, $sql, $rs_attrs, $rows, $offset ) = @_;
- # mangle the input sql as we will be replacing the selector
- $sql =~ s/^ \s* SELECT \s+ .+? \s+ (?= \b FROM \b )//ix
- or $self->throw_exception("Unrecognizable SELECT: $sql");
-
- my ($insel, $outsel) = $self->_subqueried_limit_attrs ($rs_attrs);
+ my ($stripped_sql, $insel, $outsel) = $self->_subqueried_limit_attrs ($sql, $rs_attrs);
my $qalias = $self->_quote ($rs_attrs->{alias});
my $idx_name = $self->_quote ('rownum__index');
my $order_group_having = $self->_parse_rs_attrs($rs_attrs);
+
if ($offset) {
- $sql = sprintf (<<EOS, $offset + $rows, $offset + 1 );
+ push @{$self->{limit_bind}}, [ $self->__total_bindtype => $offset + $rows ], [ $self->__offset_bindtype => $offset + 1 ];
+ return <<EOS;
SELECT $outsel FROM (
SELECT $outsel, ROWNUM $idx_name FROM (
- SELECT $insel ${sql}${order_group_having}
- ) $qalias WHERE ROWNUM <= %u
-) $qalias WHERE $idx_name >= %u
-
+ SELECT $insel ${stripped_sql}${order_group_having}
+ ) $qalias WHERE ROWNUM <= ?
+) $qalias WHERE $idx_name >= ?
EOS
+
}
else {
- $sql = sprintf (<<EOS, $rows );
+ push @{$self->{limit_bind}}, [ $self->__rows_bindtype => $rows ];
+ return <<EOS;
SELECT $outsel FROM (
- SELECT $insel ${sql}${order_group_having}
- ) $qalias WHERE ROWNUM <= %u
-
+ SELECT $insel ${stripped_sql}${order_group_having}
+ ) $qalias WHERE ROWNUM <= ?
EOS
- }
- return $sql;
+ }
}
-=head2 Top
-
- SELECT * FROM
-
- SELECT TOP $limit FROM (
- SELECT TOP $limit FROM (
- SELECT TOP ($limit+$offset) ...
- ) ORDER BY $reversed_original_order
- ) ORDER BY $original_order
-
-Unreliable Top-based implementation, supported by B<< MSSQL < 2005 >>.
-
-=head3 CAVEAT
-
-Due to its implementation, this limit dialect returns B<incorrect results>
-when $limit+$offset > total amount of rows in the resultset.
-
-=cut
-sub _Top {
- my ( $self, $sql, $rs_attrs, $rows, $offset ) = @_;
-
- # mangle the input sql as we will be replacing the selector
- $sql =~ s/^ \s* SELECT \s+ .+? \s+ (?= \b FROM \b )//ix
- or $self->throw_exception("Unrecognizable SELECT: $sql");
+# used by _Top and _FetchFirst
+sub _prep_for_skimming_limit {
+ my ( $self, $sql, $rs_attrs ) = @_;
# get selectors
- my ($in_sel, $out_sel, $alias_map, $extra_order_sel)
- = $self->_subqueried_limit_attrs ($rs_attrs);
+ my (%r, $alias_map, $extra_order_sel);
+ ($r{inner_sql}, $r{in_sel}, $r{out_sel}, $alias_map, $extra_order_sel)
+ = $self->_subqueried_limit_attrs ($sql, $rs_attrs);
my $requested_order = delete $rs_attrs->{order_by};
-
- my $order_by_requested = $self->_order_by ($requested_order);
+ $r{order_by_requested} = $self->_order_by ($requested_order);
# make up an order unless supplied
- my $inner_order = ($order_by_requested
+ my $inner_order = ($r{order_by_requested}
? $requested_order
: [ map
{ "$rs_attrs->{alias}.$_" }
]
);
- my ($order_by_inner, $order_by_reversed);
-
# localise as we already have all the bind values we need
{
local $self->{order_bind};
- $order_by_inner = $self->_order_by ($inner_order);
+ $r{order_by_inner} = $self->_order_by ($inner_order);
my @out_chunks;
for my $ch ($self->_order_by_chunks ($inner_order)) {
push @out_chunks, \join (' ', $ch, $dir eq 'ASC' ? 'DESC' : 'ASC' );
}
- $order_by_reversed = $self->_order_by (\@out_chunks);
+ $r{order_by_reversed} = $self->_order_by (\@out_chunks);
}
# this is the order supplement magic
- my $mid_sel = $out_sel;
+ $r{mid_sel} = $r{out_sel};
if ($extra_order_sel) {
for my $extra_col (sort
{ $extra_order_sel->{$a} cmp $extra_order_sel->{$b} }
keys %$extra_order_sel
) {
- $in_sel .= sprintf (', %s AS %s',
+ $r{in_sel} .= sprintf (', %s AS %s',
$extra_col,
$extra_order_sel->{$extra_col},
);
- $mid_sel .= ', ' . $extra_order_sel->{$extra_col};
+ $r{mid_sel} .= ', ' . $extra_order_sel->{$extra_col};
}
# since whatever order bindvals there are, they will be realiased
for my $col (keys %$map) {
my $re_col = quotemeta ($col);
$_ =~ s/$re_col/$map->{$col}/
- for ($order_by_reversed, $order_by_requested);
+ for ($r{order_by_reversed}, $r{order_by_requested});
}
}
# generate the rest of the sql
- my $grpby_having = $self->_parse_rs_attrs ($rs_attrs);
+ $r{grpby_having} = $self->_parse_rs_attrs ($rs_attrs);
+
+ $r{quoted_rs_alias} = $self->_quote ($rs_attrs->{alias});
+
+ \%r;
+}
+
+=head2 Top
+
+ SELECT * FROM
+
+ SELECT TOP $limit FROM (
+ SELECT TOP $limit FROM (
+ SELECT TOP ($limit+$offset) ...
+ ) ORDER BY $reversed_original_order
+ ) ORDER BY $original_order
+
+Unreliable Top-based implementation, supported by B<< MSSQL < 2005 >>.
+
+=head3 CAVEAT
+
+Due to its implementation, this limit dialect returns B<incorrect results>
+when $limit+$offset > total amount of rows in the resultset.
- my $quoted_rs_alias = $self->_quote ($rs_attrs->{alias});
+=cut
+
+sub _Top {
+ my ( $self, $sql, $rs_attrs, $rows, $offset ) = @_;
+
+ my %l = %{ $self->_prep_for_skimming_limit($sql, $rs_attrs) };
$sql = sprintf ('SELECT TOP %u %s %s %s %s',
$rows + ($offset||0),
- $in_sel,
- $sql,
- $grpby_having,
- $order_by_inner,
+ $l{in_sel},
+ $l{inner_sql},
+ $l{grpby_having},
+ $l{order_by_inner},
);
$sql = sprintf ('SELECT TOP %u %s FROM ( %s ) %s %s',
$rows,
- $mid_sel,
+ $l{mid_sel},
$sql,
- $quoted_rs_alias,
- $order_by_reversed,
+ $l{quoted_rs_alias},
+ $l{order_by_reversed},
) if $offset;
$sql = sprintf ('SELECT TOP %u %s FROM ( %s ) %s %s',
$rows,
- $out_sel,
+ $l{out_sel},
+ $sql,
+ $l{quoted_rs_alias},
+ $l{order_by_requested},
+ ) if ( ($offset && $l{order_by_requested}) || ($l{mid_sel} ne $l{out_sel}) );
+
+ return $sql;
+}
+
+=head2 FetchFirst
+
+ SELECT * FROM
+ (
+ SELECT * FROM (
+ SELECT * FROM (
+ SELECT * FROM ...
+ ) ORDER BY $reversed_original_order
+ FETCH FIRST $limit ROWS ONLY
+ ) ORDER BY $original_order
+ FETCH FIRST $limit ROWS ONLY
+ )
+
+Unreliable FetchFirst-based implementation, supported by B<< IBM DB2 <= V5R3 >>.
+
+=head3 CAVEAT
+
+Due to its implementation, this limit dialect returns B<incorrect results>
+when $limit+$offset > total amount of rows in the resultset.
+
+=cut
+
+sub _FetchFirst {
+ my ( $self, $sql, $rs_attrs, $rows, $offset ) = @_;
+
+ my %l = %{ $self->_prep_for_skimming_limit($sql, $rs_attrs) };
+
+ $sql = sprintf ('SELECT %s %s %s %s FETCH FIRST %u ROWS ONLY',
+ $l{in_sel},
+ $l{inner_sql},
+ $l{grpby_having},
+ $l{order_by_inner},
+ $rows + ($offset||0),
+ );
+
+ $sql = sprintf ('SELECT %s FROM ( %s ) %s %s FETCH FIRST %u ROWS ONLY',
+ $l{mid_sel},
+ $sql,
+ $l{quoted_rs_alias},
+ $l{order_by_reversed},
+ $rows,
+ ) if $offset;
+
+ $sql = sprintf ('SELECT %s FROM ( %s ) %s %s FETCH FIRST %u ROWS ONLY',
+ $l{out_sel},
$sql,
- $quoted_rs_alias,
- $order_by_requested,
- ) if ( ($offset && $order_by_requested) || ($mid_sel ne $out_sel) );
+ $l{quoted_rs_alias},
+ $l{order_by_requested},
+ $rows,
+ ) if ( ($offset && $l{order_by_requested}) || ($l{mid_sel} ne $l{out_sel}) );
return $sql;
}
Otherwise we fall back to L</GenericSubQ>
=cut
+
sub _RowCountOrGenericSubQ {
my $self = shift;
my ($sql, $rs_attrs, $rows, $offset) = @_;
my $root_rsrc = $rs_attrs->{_rsroot_rsrc};
my $root_tbl_name = $root_rsrc->name;
- # mangle the input sql as we will be replacing the selector
- $sql =~ s/^ \s* SELECT \s+ .+? \s+ (?= \b FROM \b )//ix
- or $self->throw_exception("Unrecognizable SELECT: $sql");
-
my ($order_by, @rest) = do {
local $self->{quote_char};
$self->_order_by_chunks ($rs_attrs->{order_by})
"Generic Subquery Limit order criteria column '$order_by' must be unique (no unique constraint found)"
) unless $is_u;
- my ($in_sel, $out_sel, $alias_map, $extra_order_sel)
- = $self->_subqueried_limit_attrs ($rs_attrs);
+ my ($stripped_sql, $in_sel, $out_sel, $alias_map, $extra_order_sel)
+ = $self->_subqueried_limit_attrs ($sql, $rs_attrs);
my $cmp_op = $direction eq 'desc' ? '>' : '<';
my $count_tbl_alias = 'rownum__emulation';
# add the order supplement (if any) as this is what will be used for the outer WHERE
$in_sel .= ", $_" for keys %{$extra_order_sel||{}};
- $sql = sprintf (<<EOS,
+ my $rownum_cond;
+ if ($offset) {
+ $rownum_cond = 'BETWEEN ? AND ?';
+
+ push @{$self->{limit_bind}},
+ [ $self->__offset_bindtype => $offset ],
+ [ $self->__total_bindtype => $offset + $rows - 1]
+ ;
+ }
+ else {
+ $rownum_cond = '< ?';
+
+ push @{$self->{limit_bind}},
+ [ $self->__rows_bindtype => $rows ]
+ ;
+ }
+
+ return sprintf ("
SELECT $out_sel
FROM (
- SELECT $in_sel ${sql}${group_having_sql}
+ SELECT $in_sel ${stripped_sql}${group_having_sql}
) %s
-WHERE ( SELECT COUNT(*) FROM %s %s WHERE %s $cmp_op %s ) %s
+WHERE ( SELECT COUNT(*) FROM %s %s WHERE %s $cmp_op %s ) $rownum_cond
$order_sql
-EOS
- ( map { $self->_quote ($_) } (
- $rs_attrs->{alias},
- $root_tbl_name,
- $count_tbl_alias,
- "$count_tbl_alias.$unq_sort_col",
- $order_by,
- )),
- $offset
- ? sprintf ('BETWEEN %u AND %u', $offset, $offset + $rows - 1)
- : sprintf ('< %u', $rows )
- ,
- );
-
- return $sql;
+ ", map { $self->_quote ($_) } (
+ $rs_attrs->{alias},
+ $root_tbl_name,
+ $count_tbl_alias,
+ "$count_tbl_alias.$unq_sort_col",
+ $order_by,
+ ));
}
# turned into a column alias (otherwise names in subqueries clash
# and/or lose their source table)
#
-# Returns inner/outer strings of SQL QUOTED selectors with aliases
-# (to be used in whatever select statement), and an alias index hashref
-# of QUOTED SEL => QUOTED ALIAS pairs (to maybe be used for string-subst
-# higher up).
+# Returns mangled proto-sql, inner/outer strings of SQL QUOTED selectors
+# with aliases (to be used in whatever select statement), and an alias
+# index hashref of QUOTED SEL => QUOTED ALIAS pairs (to maybe be used
+# for string-subst higher up).
# If an order_by is supplied, the inner select needs to bring out columns
# used in implicit (non-selected) orders, and the order condition itself
# needs to be realiased to the proper names in the outer query. Thus we
# QUOTED ALIAS pairs, which is a list of extra selectors that do *not*
# exist in the original select list
sub _subqueried_limit_attrs {
- my ($self, $rs_attrs) = @_;
+ my ($self, $proto_sql, $rs_attrs) = @_;
$self->throw_exception(
'Limit dialect implementation usable only in the context of DBIC (missing $rs_attrs)'
) unless ref ($rs_attrs) eq 'HASH';
+ # mangle the input sql as we will be replacing the selector entirely
+ unless (
+ $rs_attrs->{_selector_sql}
+ and
+ $proto_sql =~ s/^ \s* SELECT \s* \Q$rs_attrs->{_selector_sql}//ix
+ ) {
+ $self->throw_exception("Unrecognizable SELECT: $proto_sql");
+ }
+
my ($re_sep, $re_alias) = map { quotemeta $_ } ( $self->{name_sep}, $rs_attrs->{alias} );
+ # insulate from the multiple _recurse_fields calls below
+ local $self->{select_bind};
+
# correlate select and as, build selection index
my (@sel, $in_sel_index);
for my $i (0 .. $#{$rs_attrs->{select}}) {
push @sel, {
sql => $sql_sel,
- unquoted_sql => do { local $self->{quote_char}; $self->_recurse_fields ($s) },
+ unquoted_sql => do {
+ local $self->{quote_char};
+ $self->_recurse_fields ($s);
+ },
as =>
$sql_alias
||
push @out_sel, $self->_quote ($node->{as});
}
}
-
# see if the order gives us anything
my %extra_order_sel;
for my $chunk ($self->_order_by_chunks ($rs_attrs->{order_by})) {
}
return (
+ $proto_sql,
(map { join (', ', @$_ ) } (
\@in_sel,
\@out_sel)