DBIx::DBStag::Constraint (3pm)

A constraint is a recursive structure for representing query constraints;

  AND ---  x=1
    \
     \---- OR   ---  y>2
            \
             \-----  boolfunc(z)

A constraint is either a bool (\s-1AND\s0, \s-1OR\s0, \s-1NOT\s0) with >0 children, or it can be a leaf node representing an atomic constraint

the constraint corresponds to a SQLTemplate option block; eg

[ name LIKE &name& ] [ name => &name& ] [ start > &min_start& ] [ start => &start& ] [ somefunc(&x&) ] [ somefunc(&x&, &y&) ] [ somefunc(t.col, &x&, &y&) => &z& ]

the constraint consists of an operator (represented by => in the option block). If no => is present, then it is a simple variable binding.

A constraint can consist of multiple variable bindings

<http://stag.sourceforge.net>

Chris Mungall <[email protected]>

Copyright (c) 2003 Chris Mungall

This module is free software. You may distribute this module under the same terms as perl itself