--- a/Lib/IMPL/SQL/Schema/Constraint.pm	Fri Jan 25 00:25:02 2013 +0400
+++ b/Lib/IMPL/SQL/Schema/Constraint.pm	Mon Jan 28 02:43:14 2013 +0400
@@ -2,7 +2,7 @@
 use strict;
 use warnings;
 
-use IMPL::lang qw(:declare is);
+use IMPL::lang qw(:declare is isclass);
 
 use parent qw(IMPL::Object IMPL::Object::Disposable);
 
@@ -29,7 +29,7 @@
 sub ResolveColumn {
     my ($Table,$Column) = @_;
     
-    my $cn = UNIVERSAL::isa($Column,'IMPL::SQL::Schema::Column') ? $Column->name : $Column;
+    my $cn = is($Column,'IMPL::SQL::Schema::Column') ? $Column->name : $Column;
     
     my $resolved = $Table->GetColumn($cn);
     die new IMPL::InvalidOperationException("The column is not found in the table", $cn, $Table->name) if not $resolved;
@@ -74,7 +74,7 @@
 sub ResolveAlias {
     my ($self,$alias) = @_;
     
-    return is($alias, typeof IMPL::SQL::Schema::Constraint) ? $alias : $aliases{$alias};
+    return isclass($alias, typeof IMPL::SQL::Schema::Constraint) ? $alias : $aliases{$alias};
 }
 
 sub RegisterAlias {