From ec2db8acc34c988b7ef5a32e48d95ceafb15e8fc Mon Sep 17 00:00:00 2001
From: Rodrigo Kochenburger <divoxx@gmail.com>
Date: Sun, 14 Sep 2008 15:03:56 -0300
Subject: [PATCH] Add set_column_accept_null method to AlterTableGenerator

---
 lib/sequel_core/schema/generator.rb |  5 +++++
 lib/sequel_core/schema/sql.rb       |  2 ++
 spec/sequel_core/schema_spec.rb     | 14 ++++++++++++++
 3 files changed, 21 insertions(+)

diff --git a/lib/sequel_core/schema/generator.rb b/lib/sequel_core/schema/generator.rb
index b1d74f091b..21ebd95a3c 100644
--- a/lib/sequel_core/schema/generator.rb
+++ b/lib/sequel_core/schema/generator.rb
@@ -260,6 +260,11 @@ def set_column_default(name, default)
       def set_column_type(name, type)
         @operations << {:op => :set_column_type, :name => name, :type => type}
       end
+      
+      # Modify a column's NOT NULL constraint.
+      def set_column_accept_null(name, accept_null)
+        @operations << {:op => :set_column_null, :name => name, :null => accept_null}
+      end
 
       private
 
diff --git a/lib/sequel_core/schema/sql.rb b/lib/sequel_core/schema/sql.rb
index e19be0925d..ebcdb598fc 100644
--- a/lib/sequel_core/schema/sql.rb
+++ b/lib/sequel_core/schema/sql.rb
@@ -33,6 +33,8 @@ def alter_table_sql(table, op)
           "ALTER COLUMN #{quoted_name} TYPE #{op[:type]}"
         when :set_column_default
           "ALTER COLUMN #{quoted_name} SET DEFAULT #{literal(op[:default])}"
+        when :set_column_null
+          "ALTER COLUMN #{quoted_name} #{op[:null] ? 'DROP' : 'SET'} NOT NULL"
         when :add_index
           return index_definition_sql(table, op)
         when :drop_index
diff --git a/spec/sequel_core/schema_spec.rb b/spec/sequel_core/schema_spec.rb
index 6f2c763d66..e34d94fa57 100644
--- a/spec/sequel_core/schema_spec.rb
+++ b/spec/sequel_core/schema_spec.rb
@@ -459,6 +459,20 @@
   setup do
     @db = SchemaDummyDatabase.new
   end
+  
+  specify "should allow adding not null constraint" do
+    @db.alter_table(:cats) do
+      set_column_accept_null :score, false
+    end
+    @db.sqls.should == ["ALTER TABLE cats ALTER COLUMN score SET NOT NULL"]
+  end
+  
+  specify "should allow droping not null constraint" do
+    @db.alter_table(:cats) do
+      set_column_accept_null :score, true
+    end
+    @db.sqls.should == ["ALTER TABLE cats ALTER COLUMN score DROP NOT NULL"]
+  end
 
   specify "should support add_column" do
     @db.alter_table(:cats) do