in reply to Fishing for constraint => SQL designs
You could describe the rules in XML:
<table name="foo"> <field name="a" required="1"/> <field name="b" validate="\d+\.\d+\.\d+"/> <field name="c" required="if a"/> </table>
These could be easily translated to perl:
package Model::Validate::Foo; sub on_insert { my %value_of = @_; if ( !$value_of{a} ) { die "a is required"; } if ( $value_of{b} !~ /\d+\.\d+\.\d+/ ) { die "invalid b"; } if ( !$value_of{c} ) { die "c is required if a" if $value_of{a}; } }
Or, perhaps you could have constraints declared like this:
<table name="foo"> ... <constraint name="avg_a" value="average(a) > 100"/> </table>
Which would generate a sub like:
sub avg_a { # called on insert, update of table foo # check if average(a) > 100 }
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