Merge pull request #506 from pierrickrouxel/db2_is_null_fix

[DB2] fix db2 = null issue

Author: kares

lib/arjdbc/db2/adapter.rb

@@ -428,6 +428,11 @@ def runstats_for_table(tablename, priority = 10)
       @connection.execute_update "call sysproc.admin_cmd('RUNSTATS ON TABLE #{tablename} WITH DISTRIBUTION AND DETAILED INDEXES ALL UTIL_IMPACT_PRIORITY #{priority}')"
     end
 
+    def select(sql, name, binds)
+      # DB2 does not like "= NULL", "!= NULL", or "<> NULL".
+      exec_query(to_sql(sql.gsub(/(!=|<>)\s*null/i, "IS NOT NULL").gsub(/=\s*null/i, "IS NULL"), binds), name, binds)
+    end
+
     def add_index(table_name, column_name, options = {})
       if ! zos? || ( table_name.to_s == ActiveRecord::Migrator.schema_migrations_table_name.to_s )
         column_name = column_name.to_s if column_name.is_a?(Symbol)

test/db/db2/simple_test.rb

@@ -114,5 +114,21 @@ def test_find_by_sql_WITH_statement
     assert_equal db.id, connection.last_insert_id
     #assert_equal e.id, connection.last_insert_id('entries')
   end
+  
+  # DB2 does not like "= NULL".
+  def test_equals_null
+    Entry.create!(:title => "Foo")
+    entry = Entry.find(:first, :conditions => ["content = NULL"])
+    assert_equal "Foo", entry.title
+  end
+
+  # DB2 does not like "!= NULL" or "<> NULL".
+  def test_not_equals_null
+    Entry.create!(:title => "Foo", :content => "Bar")
+    entry = Entry.find_by_title("Foo", :conditions => ["content != NULL"])
+    assert_equal "Foo", entry.title
+    entry = Entry.find_by_title("Foo", :conditions => ["content <> NULL"])
+    assert_equal "Foo", entry.title
+  end
 
 end