--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Lib/IMPL/SQL/Schema.pm	Mon Nov 09 01:39:31 2009 +0300
@@ -0,0 +1,94 @@
+use strict;
+package IMPL::SQL::Schema;
+
+use base qw(IMPL::Object IMPL::Object::Disposable);
+use IMPL::Class::Property;
+use IMPL::Class::Property::Direct;
+
+require IMPL::SQL::Schema::Table;
+
+BEGIN {
+    public _direct property Version => prop_get;
+    public _direct property Name => prop_get;
+    public _direct property Tables => prop_get;
+}
+
+sub AddTable {
+    my ($this,$table) = @_;
+    
+    if (UNIVERSAL::isa($table,'IMPL::SQL::Schema::Table')) {
+        $table->Schema == $this or die new IMPL::InvalidOperationException('The specified table must belong to the database');
+        not exists $this->{$Tables}->{$table->Name} or die new IMPL::InvalidOperationException('a table with the same name already exists in the database');
+    } elsif (UNIVERSAL::isa($table,'HASH')) {
+        not exists $this->{$Tables}->{$table->{'Name'}} or die new IMPL::InvalidOperationException('a table with the same name already exists in the database');
+        $table->{'Schema'} = $this;
+        $table = new IMPL::SQL::Schema::Table(%{$table});
+    } else {
+        die new IMPL::InvalidArgumentException('Either a table object or a hash with table parameters is required');
+    }
+    
+    $this->{$Tables}{$table->Name} = $table;
+}
+
+sub RemoveTable {
+    my ($this,$table) = @_;
+    
+    my $tn = UNIVERSAL::isa($table,'IMPL::SQL::Schema::Table') ? $table->Name : $table;
+    $table = delete $this->{$Tables}{$tn} or die new IMPL::InvalidArgumentException('The table doesn\'t exists',$tn);
+    
+    # drop foreign keys
+    map { $_->Table->RemoveConstraint($_) } values %{$table->PrimaryKey->ConnectedFK} if $table->PrimaryKey;
+    
+    # drop table contents
+    $table->Dispose();
+
+    return 1;
+}
+
+sub Dispose {
+    my ($this) = @_;
+    
+    $_->Dispose foreach values %{$this->{$Tables}};
+    
+    delete $this->{$Tables};
+    
+    $this->SUPER::Dispose;
+}
+
+1;
+
+__END__
+=pod
+
+=head1 SINOPSYS
+
+require IMPL::SQL::Schema;
+use IMPL::SQL::Types qw(Varchar Integer);
+
+my $dbSchema = new IMPL::SQL::Schema;
+
+my $tbl = $dbSchema->AddTable({Name => 'Person' });
+$tbl->AddColumn({
+    Name => 'FirstName',
+    CanBeNull => 1,
+    Type => Varchar(255)
+});
+$tbl->AddColumn({
+    Name => 'Age',
+    Type => Integer
+});
+
+# so on
+
+# and finally don't forget to
+
+$dbSchema->Dispoce();
+
+=head1 DESCRIPTION
+
+Схема реляциоонной базы данных, орентированная на язык SQL, содержит описания таблиц
+которые являются частью базы. Позволяет создавать и удалать таблицы.
+
+Имея две схемы можно создавать скрипты для примениения изменений схемы данных C<<IMPL::SQL::Traits>>
+
+=cut