--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Lib/Schema/DB/Column.pm	Tue Jul 14 12:54:37 2009 +0400
@@ -0,0 +1,56 @@
+package Schema::DB::Column;
+use Common;
+our @ISA = qw(Object);
+
+BEGIN {
+    DeclareProperty Name => ACCESS_READ;
+    DeclareProperty Type => ACCESS_READ;
+    DeclareProperty CanBeNull => ACCESS_READ;
+    DeclareProperty DefaultValue => ACCESS_READ;
+    DeclareProperty Tag => ACCESS_READ;
+}
+
+sub CTOR {
+    my $this = shift;
+    $this->SUPER::CTOR(@_);
+    
+    $this->{$Name} or die new Exception('a column name is required');
+    $this->{$CanBeNull} = 0 if not exists $this->{$CanBeNull};
+    UNIVERSAL::isa($this->{$Type},'Schema::DB::Type') or die new Exception('a type is required for the column',$this->{$Name});
+}
+
+sub isEqualsStr {
+    my ($a,$b) = @_;
+    
+    if (defined $a and defined $b) {
+        return $a eq $b;
+    } else {
+        if (defined $a or defined $b) {
+            return 0;
+        } else {
+            return 1;
+        }
+    }
+}
+
+sub isEquals {
+    my ($a,$b) = @_;
+    
+    if (defined $a and defined $b) {
+        return $a == $b;
+    } else {
+        if (defined $a or defined $b) {
+            return 0;
+        } else {
+            return 1;
+        }
+    }
+}
+
+sub isSame {
+    my ($this,$other) = @_;
+    
+    return ($this->{$Name} eq $other->{$Name} and $this->{$CanBeNull} == $other->{$CanBeNull} and isEqualsStr($this->{$DefaultValue}, $other->{$DefaultValue}) and $this->{$Type}->isSame($other->{$Type}));
+}
+
+1;