--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/IMPL/SQL/Schema/Constraint/PrimaryKey.pm	Fri Sep 04 19:40:23 2015 +0300
@@ -0,0 +1,42 @@
+package IMPL::SQL::Schema::Constraint::PrimaryKey;
+use strict;
+use parent qw(IMPL::SQL::Schema::Constraint::Index);
+use IMPL::Class::Property;
+
+__PACKAGE__->PassThroughArgs;
+__PACKAGE__->RegisterAlias('pk');
+
+BEGIN {
+    public _direct property connectedFK => prop_get;
+}
+
+sub CTOR {
+    my ($this,%args) = @_;
+    
+    $this->{$connectedFK} = {};
+}
+
+sub ConnectFK {
+    my ($this,$FK) = @_;
+    
+    UNIVERSAL::isa($FK,'IMPL::SQL::Schema::Constraint::ForeignKey') or die new Exception('Aprimary key could be connected only to a foreign key');
+    not exists $this->{$connectedFK}->{$FK->uniqName} or die new Exception('This primary key already conneted with the specified foreing key',$FK->name,$FK->table->name);
+    
+    $this->{$connectedFK}->{$FK->uniqName} = $FK;
+}
+
+sub DisconnectFK {
+    my ($this,$FK) = @_;
+    
+    delete $this->{$connectedFK}->{$FK->uniqName};
+}
+
+sub Dispose {
+    my ($this) = @_;
+    
+    delete $this->{$connectedFK};
+    
+    $this->SUPER::Dispose;
+}
+
+1;