What is SQL Server's SYSNAME Data Type and When Should You Use It?

Delving into SQL Server's SYSNAME Data Type

In the realm of relational databases, the SYSNAME data type in SQL Server serves a unique purpose. As documented in the SQL Server Books Online, it is designed specifically to store object names within database tables, variables, and stored procedure parameters. However, understanding its precise usage might require a practical example.

To illustrate, consider the following scenario: you want to create a stored procedure that accepts a table name as an input parameter. To ensure that the procedure can handle various table names, you would use the SYSNAME data type. This type restricts the input to compliant object names, safeguarding against potential errors.

Technically, SYSNAME is analogous to nvarchar(128) NOT NULL. It enforces the storage of object names within a character limit of 128 Unicode characters and prevents null values. This constraint is designed to align with SQL Server's rules for identifying database objects, ensuring consistency and preventing ambiguous or invalid object references.

While SYSNAME has its defined purpose, it's important to note that its usage is primarily internal to SQL Server. It is commonly employed in system tables and stored procedures maintained by Microsoft. For general database applications, the use of nvarchar with appropriate constraints is generally preferred.

In summary, the SYSNAME data type in SQL Server is a restricted character data type specifically tailored for storing object names, helping to ensure the integrity and validity of object references within database operations.

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