--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Lib/IMPL/ORM/Schema.pm	Mon Oct 19 04:13:54 2009 +0400
@@ -0,0 +1,64 @@
+package IMPL::ORM::Schema;
+use strict;
+use warnings;
+
+use base qw(IMPL::DOM::Document);
+use IMPL::Class::Property;
+
+BEGIN {
+    public property mapValueTypes => prop_get | owner_set;
+    public property mapReferenceTypes => prop_get | owner_set;
+}
+
+sub CTOR {
+    my ($this ) = @_;
+    $this->mapValueTypes({});
+    $this->mapReferenceTypes({});
+}
+
+# return an entity for the specified typename
+# makes forward declaration if nesessary
+sub resolveType {
+    my ($this,$typeName) = @_;
+    
+    $this = ref $this ? $this : $this->instance;
+    
+    if (my $entity = $this->mapReferenceTypes->{$typeName}) {
+        return $entity;
+    } elsif (UNIVERSAL::isa($typeName,'IMPL::ORM::Object')) {
+        return $this->declareReferenceType($typeName);
+    } else {
+        return undef;
+    }
+}
+
+# returns valuetype name
+sub isValueType {
+    my ($this,$typeName) = @_;
+    
+    $this = ref $this ? $this : $this->instance;
+    
+    return $this->mapValueTypes->{$typeName};
+}
+
+my %instances;
+sub instance {
+    my ($class) = @_;
+    
+    return ($instances{$class} || ($instances{$class} = $class->new));
+}
+
+1;
+
+__END__
+
+=pod
+
+=head1 DESCRIPTION
+
+Схема данных, представляет собой DOM документ, элементами которой
+являются сущности.
+
+Каждый узел - это описание сущности.
+
+=cut
\ No newline at end of file