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Re: Fishing for constraint => SQL designs

by nferraz (Monk)
on May 23, 2007 at 10:32 UTC ( #616969=note: print w/replies, xml ) Need Help??

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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