Setting and Changing Collations
Collations can be specified at the server, database, column, expression, and identifier levels. When you install an instance of SQL Server, you specify the default server collation for that instance. Each time that you create a database, you can specify the default collation used for the database. If you do not specify a collation, the default collation for the database is the default collation for the server instance. Whenever you define a character column, variable, or parameter, you can specify the collation of the object. If you do not specify a collation, the object is created by using the default collation of the database.
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.
The following topics explain how to work with collations at the server, database, column, expression, and identifier levels: