How Can I Safely Pass a Table Name as a Parameter to a SQL Server Stored Procedure?

Securely Passing Table Names to SQL Server Stored Procedures

Dynamically passing table names to stored procedures enhances database flexibility. However, security must be paramount. This guide details best practices for this common task in SQL Server.

Preventing SQL Injection:

Directly concatenating user inputs into SQL queries is a major vulnerability. This opens the door to SQL injection attacks.

Employing Parameterization:

Parameterized queries are the cornerstone of secure parameter passing. Using placeholders (e.g., ?) prevents malicious input from being interpreted as SQL code. The database system handles proper escaping.

Dynamic Table Name Resolution:

Dynamic SQL, combined with proper validation, allows safe retrieval of table names. Here's an example:

<code class="language-sql">CREATE PROC spCountAnyTableRows (@PassedTableName VARCHAR(255))
AS
BEGIN
    DECLARE @ActualTableName VARCHAR(255);

    SELECT @ActualTableName = QUOTENAME(TABLE_NAME)
    FROM INFORMATION_SCHEMA.TABLES
    WHERE TABLE_NAME = @PassedTableName;

    DECLARE @SQL NVARCHAR(MAX);
    SET @SQL = N'SELECT COUNT(*) FROM ' + @ActualTableName + N';';

    EXEC sp_executesql @SQL;
END;</code>

This approach verifies the table name exists before constructing and executing the query, minimizing injection risks.

Key Considerations:

• QUOTENAME is crucial for escaping special characters, but it's not a complete security solution on its own. Always combine it with table existence checks.
• Parameterization extends beyond table names; it's essential for dynamic column names and other database objects.
• Stored procedures provide a structured and secure approach to dynamic SQL compared to inline parameterized queries.

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