What is “sysname” data type used for object names?

You might have noticed that the data type of object names such as database name is “sysname” which is not listed in data type list when creating a table via table designer. This data type can be clearly seen when creating objects using templates (CREATE DATABASE template). What is this sysname data type? Can we use it? Should we use it?

Sysname is a built-in system data type defined as nvarchar(128). Initially, with older versions (up to 6.5 if I am not mistaken, TBV) it was equivalent to varchar(30). It is a non-nullable data type and mainly used to store object names. This data type is not listed in data-type list which comes when creating tables via table designer. However, it can be used for defining columns for tables when they are created using T-SQL. Have a look on following code;

-- using sysname for variables

DECLARE @TestVariable sysname = 'Test Value'

SELECT @TestVariable

GO

-- using sysname for creating tables

CREATE TABLE dbo.TestTable

(

    Id int PRIMARY KEY

    , Name sysname

)

GO

If your system is configured with case-sensitive collation, make sure you type the word in lowercase.

As you see, it can be used with our codes. However, many recommend not to use because of; 1. nvarchar(128) can be simply used instead, 2. there can be a change in future version. Therefore, even though it is possible to use sysname data type with T-SQL, it is better not to use.