User defined data types

[Raj Ali]

Sir, How to make a user defined data types by query in sql Thanx Raj Ali

[justsomeguy]

If you are using SQL Server, this might help:http://www.mssqlcity.com/Articles/General/...e_data_type.htm

SQL Server 2000 supports user-defined data types too. User-defined data types provide a mechanism for applying a name to a data type that is more descriptive of the types of values to be held in the object. Using user-defined data type can make it easier for a programmer or database administrator to understand the intended use of any object defined with the data type. The user-defined data types are based on the system data types and can be used to predefine several attributes of a column, such as its data type, length, and whether it supports NULL values. To create a user-defined data type, you can use the sp_addtype system stored procedure or you could add one using the Enterprise Manager. When you create a user-defined data type, you should specify the following three properties:Data type's name.Built-in data type upon which the new data type is based.Whether it can contain NULL values.The following example creates a user-defined data type based on money data type named cursale that cannot be NULL:EXEC sp_addtype cursale, money, 'NOT NULL'Both system and user-defined data types are used to enforce data integrity. It is very important that we put a lot of effort while designing tables: the better you design your tables, the more time you can work without any performance problems. In an ideal case, you never will update the structure of your tables.

Wow, I was not aware of this:

Use char/varchar columns instead of nchar/nvarchar if you do not need to store unicode data.The char/varchar value uses only one byte to store one character, the nchar/nvarchar value uses two bytes to store one character, so the char/varchar columns use two times less space to store data in comparison with nchar/nvarchar columns.

Goodbye nvarchar!