What is the SYSNAME data type in SQL Server?

sql

sql-injection

dynamic-sql

metadata-operations

byAnton Shumikhin·Mar 12, 2025

SYSNAME is a built-in data type in SQL Server, effectively an alias for NVARCHAR(128). It's primarily used to store object names in SQL scripts, aiding SQL Server in maintaining consistency and accuracy.

Example:

DECLARE @ColumnName SYSNAME = N'LastName'; -- Hello, Surname Entity! 🖐️
EXEC sp_help @ColumnName; -- You've got a friend in SQL! 🤝

By declaring @ColumnName as SYSNAME, the script ensures a valid SQL Server identifier is stored, reducing risks of mismatch errors.

SYSNAME is, by default, non-nullable, and is most commonly found in system tables and stored procedures where object names are stored. Despite its extensive internal use, SYSNAME isn't typical in business application scenarios.

When working with dynamic SQL and metadata operations, SYSNAME shines, as it inherently validates object names, preventing potential SQL-injection or invalid naming issues.

When and Why to use SYSNAME

Code Language Consistency

Choose SYSNAME for declaration of SQL object names. This reinforces code language unity and eliminates potential missteps in referencing database objects.

Dynamic SQL

SYSNAME brings added benefits to dynamic SQL. Since it inherently validates object names, you get protection against potential SQL-injection and invalid naming problems. Yes, SYSNAME is your SQL Server bodyguard! 😎

Sys Procedures and Macros

System-stored procedures such as sp_send_dbmail, which uses SYSNAME for profile_name parameter, showcase how SYSNAME works within system procedures. It's a tactical tool in SQL Server's operation toolkit.

Metadata Operations

Working with metadata operations or crafting scripts detailing system information? SYSNAME comes to your rescue to ensure accuracy and uniformity.

SYSNAME for Nerds: Advanced Insights 💡

Data Type Insights

Use the sys.types query to retrieve SYSNAME properties. Join sys.parameters with sys.types to get an overview of parameters' data types. Here, SYSNAME's system_type_id is 231, and user_type_id is 256.

SELECT * FROM sys.types WHERE name = 'sysname'; -- SYSNAME's very own backstage pass! 🎬

This provides detailed data type metadata, providing useful insights into SQL Server's internal operations.

SYSNAME in action

In forensic analysis or complex metadata tasks, SYSNAME is essential. Suppose you're retrieving a table's schema, identifying security settings, or finding a table's owner - SYSNAME ensures faultless database object references.

Pro Tips for SYSNAME Usage ⚙️

Square Bracket Policy: Always use Square Brackets or QUOTENAME when forming Dynamic SQL with SYSNAME to avoid SQL injection.
Instance Check: SYSNAME behavior can vary across SQL Server instances. Always verify before using.
Stick to rules: SQL Server identifiers adhere to specific rules about what constitutes a valid name; SYSNAME follows suit.