SQL Server 2008: Bulk Datatype Change

Question

I have an SQL Server 2008 database with many tables. I\'ve been using the now lame datetime datatype and want to use the new and better datetime2.

Answer 1

Data type alteration generally requires ALTER TABLE statements:

ALTER TABLE myTable ALTER COLUMN timestamp datetime2 [NOT] NULL

To change all the datetime columns into datetime2 in a given database & schema:

DECLARE @SQL AS NVARCHAR(4000)
DECLARE @table_name AS NVARCHAR(255)
DECLARE @column_name AS NVARCHAR(255)
DECLARE @isnullable AS BIT

DECLARE CUR CURSOR FAST_FORWARD FOR
    SELECT c.table_name, 
           c.column_name, 
           CASE WHEN c.is_nullable = 'YES' THEN 1 ELSE 0 END AS is_nullable
      FROM INFORMATION_SCHEMA.COLUMNS c 
     WHERE c.data_type = 'datetime'
       AND c.table_catalog = 'your_database'
       AND c.table_schema = 'your_schema'
    -- AND c.table_name = 'your_table'

OPEN CUR
FETCH NEXT FROM CUR INTO @table_name, @column_name, @isnullable
WHILE @@FETCH_STATUS = 0
BEGIN
    SELECT @SQL = 'ALTER TABLE ' + @table_name + ' ALTER COLUMN ' + @column_name + ' datetime2' + (CASE WHEN @isnullable = 1 THEN '' ELSE ' NOT' END) + ' NULL;'
    EXEC sp_executesql @SQL
    FETCH NEXT FROM CUR INTO @table_name, @column_name, @isnullable
END

CLOSE CUR;
DEALLOCATE CUR;