Monday, August 12, 2019

SQL - What is sp_executesql system stored procedure in SQL Server

In this blog, we will discuss about sp_executesql stored procedure and what advantage sp_executesql stored procedure have it over EXEC.

sp_executesql is system stored procedure, it is used to execute the SQL script like EXEC but sp_executesql allows for SQL statement to be parameterized as instead of embedding or injecting it into SQL code so it stops any SQL Injection possibility.

There are some other difference between Exec and sp_executesql

Allow for statement to be parameterized
There is no option for parameterize column
No Risk of SQL Injection
High Risk of SQL Injection
Strongly typed parameters
No Strongly typed parameters
Performance Benefits - Cache an execution plane on first run
Create an execution plan for each run

Here is an example of sp_executesql:

CREATE PROCEDURE dbo.usp_validate_user
     @UserName as varchar(10),
     @Password as varchar(10)
     declare @sqlString as varchar(max)
     SET @sqlString = 'Select id from dbo.Users Where UserName = @UserName and password = @Password'

     EXECUTE sp_executesql @sqlString,
     N'@UserName as varchar(10),  @Password as varchar(10)'
       @UserName,  @Password


SQL Server - Identify unused indexes

 In this blog, we learn about the index usage information (SYS.DM_DB_INDEX_USAGE_STATS) and analyze the index usage data (USER_SEEKS, USER_S...