Change collations of all columns of all tables in SQL Server

Question

I imported a database with some data to compare with another database.

The target database has collation Latin1_General_CI_AS and the source database has SQL_Latin1_General_CP1_CI_AS.

I did change the collation of the source database in general to Latin1_General_CI_AS using the SQL Server Management Studio. But the tables and columns inside remains with the old collation.

I know that I can change a column using:

ALTER TABLE [table] 
ALTER COLUMN [column] VARCHAR(100) COLLATE Latin1_General_CI_AS

But I have to do this for all tables and all columns inside.

Before I know start to write a stored procedure that reads all tables and inside all column of type varchar and change them in a table and column cursor loop...

Does anyone know an easier way or is the only way to do this with a script running through all tables in a procedure?

Answer 1

As I did not find a proper way I wrote a script to do it and I'm sharing it here for those who need it. The script runs through all user tables and collects the columns. If the column type is any char type then it tries to convert it to the given collation.

Columns has to be index and constraint free for this to work.

If someone still has a better solution to this please post it!

DECLARE @collate nvarchar(100);
DECLARE @table nvarchar(255);
DECLARE @column_name nvarchar(255);
DECLARE @column_id int;
DECLARE @data_type nvarchar(255);
DECLARE @max_length int;
DECLARE @row_id int;
DECLARE @sql nvarchar(max);
DECLARE @sql_column nvarchar(max);

SET @collate = 'Latin1_General_CI_AS';

DECLARE local_table_cursor CURSOR FOR

SELECT [name]
FROM sysobjects
WHERE OBJECTPROPERTY(id, N'IsUserTable') = 1

OPEN local_table_cursor
FETCH NEXT FROM local_table_cursor
INTO @table

WHILE @@FETCH_STATUS = 0
BEGIN

    DECLARE local_change_cursor CURSOR FOR

    SELECT ROW_NUMBER() OVER (ORDER BY c.column_id) AS row_id
        , c.name column_name
        , t.Name data_type
        , c.max_length
        , c.column_id
    FROM sys.columns c
    JOIN sys.types t ON c.system_type_id = t.system_type_id
    LEFT OUTER JOIN sys.index_columns ic ON ic.object_id = c.object_id AND ic.column_id = c.column_id
    LEFT OUTER JOIN sys.indexes i ON ic.object_id = i.object_id AND ic.index_id = i.index_id
    WHERE c.object_id = OBJECT_ID(@table)
    ORDER BY c.column_id

    OPEN local_change_cursor
    FETCH NEXT FROM local_change_cursor
    INTO @row_id, @column_name, @data_type, @max_length, @column_id

    WHILE @@FETCH_STATUS = 0
    BEGIN

        IF (@max_length = -1) OR (@max_length > 4000) SET @max_length = 4000;

        IF (@data_type LIKE '%char%')
        BEGIN TRY
            SET @sql = 'ALTER TABLE ' + @table + ' ALTER COLUMN ' + @column_name + ' ' + @data_type + '(' + CAST(@max_length AS nvarchar(100)) + ') COLLATE ' + @collate
            PRINT @sql
            EXEC sp_executesql @sql
        END TRY
        BEGIN CATCH
          PRINT 'ERROR: Some index or constraint rely on the column' + @column_name + '. No conversion possible.'
          PRINT @sql
        END CATCH

        FETCH NEXT FROM local_change_cursor
        INTO @row_id, @column_name, @data_type, @max_length, @column_id

    END

    CLOSE local_change_cursor
    DEALLOCATE local_change_cursor

    FETCH NEXT FROM local_table_cursor
    INTO @table

END

CLOSE local_table_cursor
DEALLOCATE local_table_cursor

GO