Stored procedures are powerful database objects that contain precompiled SQL statements.
They are stored directly in the database and can be executed multiple times with different parameters.
Think of them as reusable functions for your database operations.
To create a stored procedure, we use the CREATE PROCEDURE statement followed by the procedure name.
We can define input parameters like CustomerId. The actual SQL statements go inside a BEGIN and END block.
This example creates a procedure that retrieves customer information based on an ID parameter.
Once a stored procedure is created, you execute it using the EXEC or EXECUTE command followed by the procedure name and any required parameters.
Different database systems have slightly different syntax. SQL Server uses EXEC, while MySQL and PostgreSQL typically use CALL.
The procedure runs on the database server and returns results to the client.
Stored procedures can accept input parameters and return output parameters or result sets.
Input parameters like CustomerId and StartDate pass data into the procedure.
Output parameters like Total allow the procedure to return calculated values back to the caller.
This makes procedures flexible and reusable for different scenarios.
Stored procedures offer several key benefits. They provide improved performance because the code is precompiled and cached.
Security is enhanced as they help prevent SQL injection attacks. They promote code reusability since you write the logic once and can use it multiple times.
Business logic is centralized in the database, and network traffic is reduced because less data needs to be transferred between client and server.