Change Database Collation in Sql Server

Feedback
Edit

Set or Change the Database Collation

Article
08/02/2021
5 minutes to read

Applies to: SQL Server (all supported versions)

This topic describes how set and change the database collation by using SQL Server Management Studio or Transact-SQL. If no collation is specified, the server collation is used.

Important

ALTER DATABASE COLLATE statement on Azure SQL Database is not supported.

In This Topic

Before you begin:

Limitations and Restrictions

Recommendations

Security
To set or change the database collation, using:

SQL Server Management Studio

Transact-SQL

Before You Begin

Limitations and Restrictions

Windows Unicode-only collations can only be used with the COLLATE clause to apply collations to the nchar, nvarchar, and ntext data types on column level and expression-level data. They cannot be used with the COLLATE clause to change the collation of a database or server instance.
If the specified collation or the collation used by the referenced object uses a code page that is not supported by Windows, the Database Engine displays an error.

Recommendations

You can find the supported collation names in Windows Collation Name (Transact-SQL) and SQL Server Collation Name (Transact-SQL); or you can use the sys.fn_helpcollations (Transact-SQL) system function.

When you change the database collation, you change the following:

Any char, varchar, text, nchar, nvarchar, or ntext columns in system tables are changed to the new collation.
All existing char, varchar, text, nchar, nvarchar, or ntext parameters and scalar return values for stored procedures and user-defined functions are changed to the new collation.
The char, varchar, text, nchar, nvarchar, or ntext system data types, and all user-defined data types based on these system data types, are changed to the new default collation.

You can change the collation of any new objects that are created in a user database by using the COLLATE clause of the ALTER DATABASE statement. This statement does not change the collation of the columns in any existing user-defined tables. These can be changed by using the COLLATE clause of ALTER TABLE.

Important

Changing the collation of a database or individual columns does not modify the underlying data already stored in existing tables. Unless your application explicitly handles data conversion and comparison between different collations, it is recommended that you transition existing data in the database to the new collation. This removes the risk that applications may incorrectly modify data, resulting in possible wrong results or silent data loss.

When a database collation is changed, only new tables will inherit the new database collation by default. There are several alternatives to convert existing data to the new collation:

Convert data in-place. To convert the collation for a column in an existing table, see Set or Change the Column Collation. This operation is easy to implement, but may become a blocking issue for large tables and busy aplications. See the following example for an in-place conversion of the MyString column to a new collation:
```
                ALTER TABLE dbo.MyTable ALTER COLUMN MyString VARCHAR(50) COLLATE Latin1_General_100_CI_AI_SC_UTF8;                              
```
Copy data to new tables that use the new collation, and replace original tables in the same database. Create a new table in the current database that will inherit the database collation, copy the data between the old table and the new table, drop the original table, and rename the new table to the name of the original table. This is a faster operation than an in-place conversion, but may become a challenge when handling complex schemas with dependencies such as Foreign Key contraints, Primary Key constraints, and Triggers. It would also require a final data syncronization between the original and the new table before the final cut-off, if data continues to be changed by applications. See the following example for a "copy and replace" conversion of the MyString column to a new collation:
```
                CREATE TABLE dbo.MyTable2 (MyString VARCHAR(50) COLLATE Latin1_General_100_CI_AI_SC_UTF8);   INSERT INTO dbo.MyTable2  SELECT * FROM dbo.MyTable;   DROP TABLE dbo.MyTable;   EXEC sp_rename 'dbo.MyTable2', 'dbo.MyTable';                              
```
Copy data to a new database that uses the new collation, and replace the original database. Create a new database using the new collation, and transfer the data from the original database via tools like Integration Services or the Import/Export Wizard in SQL Server Management Studio. This is a simpler approach for complex schemas. It would also require a final data syncronization between the original and the new databases before the final cut-off, if data continues to be changed by applications.

Security

Permissions

To create a new database, requires CREATE DATABASE permission in the master database, or requires CREATE ANY DATABASE, or ALTER ANY DATABASE permission.

To change the collation of an existing database, requires ALTER permission on the database.

Using SQL Server Management Studio

To set or change the database collation

In Object Explorer, connect to an instance of the SQL Server Database Engine, expand that instance, and then expand Databases.
If you are creating a new database, right-click Databases and then click New Database. If you do not want the default collation, click the Options page, and select a collation from the Collation drop-down list.

Alternatively, if the database already exists, right-click the database that you want and click Properties. Click the Options page, and select a collation from the Collation drop-down list.
After you are finished, click OK.

Using Transact-SQL

To set the database collation

Connect to the Database Engine.
From the Standard bar, click New Query.
Copy and paste the following example into the query window and click Execute. This example shows how to use the COLLATE clause to specify a collation name. The example creates the database MyOptionsTest that uses the Latin1_General_100_CS_AS_SC collation. After you create the database, execute the SELECT statement to verify the setting.

            USE master;   GO   IF DB_ID (N'MyOptionsTest') IS NOT NULL   DROP DATABASE MyOptionsTest;   GO   CREATE DATABASE MyOptionsTest   COLLATE Latin1_General_100_CS_AS_SC;   GO      --Verify the collation setting.   SELECT name, collation_name   FROM sys.databases   WHERE name = N'MyOptionsTest';   GO

To change the database collation

Connect to the Database Engine.
From the Standard bar, click New Query.
Copy and paste the following example into the query window and click Execute. This example shows how to use the COLLATE clause in an ALTER DATABASE statement to change the collation name. Execute the SELECT statement to verify the change.

            USE master;   GO   ALTER DATABASE MyOptionsTest   COLLATE French_CI_AS ;   GO      --Verify the collation setting.   SELECT name, collation_name   FROM sys.databases   WHERE name = N'MyOptionsTest';   GO

Feedback

Change Database Collation in Sql Server

Source: https://docs.microsoft.com/en-us/sql/relational-databases/collations/set-or-change-the-database-collation?view=sql-server-ver15

Wunderlich Milatichated