A SQL stored procedure is a precompiled collection of one or more SQL statements or commands that are stored in a database. Stored procedures have a specific name and can accept input parameters, perform operations, and return results to the calling program or user. They are typically used to encapsulate and centralize business logic or commonly used database operations.
Here are some key characteristics of SQL stored procedures:
Precompiled and Stored: Stored procedures are precompiled and stored in the database, which can lead to improved performance as they don't need to be parsed and compiled every time they are executed.
Input Parameters: Stored procedures can accept input parameters, allowing them to be more versatile and adaptable to different scenarios. Parameters enable dynamic data processing within the procedure.
Code Reusability: Since stored procedures are stored in the database, they can be reused by multiple applications or users. This promotes code reusability and ensures consistent execution of logic.
Security: Stored procedures can enhance security by allowing controlled access to database operations. Users might have permission to execute a stored procedure without having direct access to the underlying tables.
Reduced Network Traffic: Executing a stored procedure involves sending only the procedure name and parameters over the network, reducing the amount of data transmitted compared to sending multiple SQL statements.
Transaction Management: Stored procedures can participate in database transactions, allowing for more complex operations to be treated as a single unit of work, either succeeding or failing as a whole.
To create a basic stored procedure in SQL, you might use syntax like the following:
CREATE PROCEDURE sp_example
@param1 INT,
@param2 VARCHAR(50)
AS
BEGIN
-- SQL statements and logic go here
SELECT * FROM ExampleTable WHERE Column1 = @param1 AND Column2 = @param2;
END;
Once created, you can execute this stored procedure by calling EXEC sp_example 1, 'ABC';, for example.