Stored Procedure in SQL: How to Create, Executive, Modify, Types & Use Cases

SQL (Structured Query Language) is a standard language that manages and manipulates relational databases. It is used for various tasks, including retrieving, updating, and deleting data. Stored procedures are a feature of SQL that allows users to save a set of SQL commands in a database and execute them as a single unit.

An SQL procedure, accurately known as the stored procedure, is a pre-compiled, reusable program stored in a database. The main advantage of using stored procedures is that they can be executed multiple times with a single command, saving time and reducing the amount of code that needs to be written. Additionally, stored procedures can be used to perform complex calculations, implement business logic, and perform other tasks that would be difficult to achieve with standard SQL commands.

Benefits of using Stored Procedures in SQL

Stored procedures have been a staple of database management in SQL for many years, with a wide range of benefits that make them an essential tool for data management. Some key benefits of using stored procedures in SQL are outlined below.

1. Improved Efficiency

By using stored procedures, you can improve the efficiency of database-driven applications by reducing the amount of data that needs to be transmitted between the application and the database. Stored procedures operate on complex data processing and calculation tasks within the database, which allows them to reduce the load on the application and improve performance.

2. Enhanced Data Integrity

Stored procedures can help to ensure that data entered into the database is accurate and meets specific validation criteria. By using stored procedures to validate data before it is saved, organisations can reduce the risk of errors and improve the overall quality of their data.

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3. Simplified Data Management

Simplifying data management becomes a straightforward task with stored procedures. They work by encapsulating complex data processing and calculation logic within the database, which allows developers to manage data, reducing the risk of errors and making it easier to maintain and update applications over time.

4. Increased Security

Restricting access to sensitive data and enforcing data access control becomes easier by using stored procedures in SQL. As a result, organisations can reduce the risk of data breaches and unauthorised access.

5. Improved Code Reusability

Stored procedures can improve code reusability by encapsulating data processing and calculation logic within the database. This makes it easier for developers to reuse code across multiple applications, reducing the time and effort required to implement new applications and features.

6. Improved Collaboration

With stored procedures, collaboration becomes a breeze. Multiple developers get to work together easily on the same data management tasks. By using stored procedures, organisations can ensure that all data management tasks are performed consistently, reducing the risk of errors and improving the overall quality of the data.

In essence, stored procedures in SQL offer a wide range of benefits that make them an essential tool for database management. Whether you are looking to improve efficiency, enhance data integrity, simplify data management, increase security, improve code reusability, or improve collaboration, stored procedures are essential in your database management toolkit.

How to create Stored Procedure in SQL?

Here’s the basic syntax that you can use in order to create stored procedure in SQL:

CREATE PROCEDURE [dbo].[StoredProcedureName] ( @parameter1 datatype, @parameter2 datatype ) AS BEGIN — SQL commands END

For example:

Source

The CREATE PROCEDURE statement is used to create a new stored procedure, followed by the stored procedure’s name and any required parameters. The AS keyword is used to begin the body of the stored procedure, which contains the SQL commands that will be executed when the stored procedure is called.

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How to execute a Stored Procedure in SQL?

To execute a stored procedure in SQL, follow the below-mentioned basic command: 

EXEC [dbo].[StoredProcedureName] @parameter1 = value1, @parameter2 = value2

For Example: After executing the stored procedure, the result will look like this-

Source

The EXEC statement is used to execute a stored procedure, followed by the name of the stored procedure and any required parameters. The values for the parameters are passed in using the = operator.

How to Modify a Stored Procedure in SQL?

The syntax for modifying a stored procedure in SQL varies depending on the specific database management system used. However, the basic syntax for modifying a stored procedure in SQL Server is as follows:

ALTER PROCEDURE [dbo].[StoredProcedureName] ( @parameter1 datatype, @parameter2 datatype ) AS BEGIN — Modified SQL commands END

For Example: 

Source

The ALTER PROCEDURE statement is used to modify an existing stored procedure, followed by the name of the stored procedure and any required parameters. The AS keyword is used to begin the body of the stored procedure, which contains the modified SQL commands that will be executed when the stored procedure is called.

How to Delete a Stored Procedure in SQL?

Here’s the basic syntax that you can use in order to delete a stored procedure in SQL

DROP PROCEDURE [dbo].[StoredProcedureName]

For Example: 

Source

The DROP PROCEDURE statement is used to delete an existing stored procedure, followed by the name of the stored procedure to be deleted.

Types of Stored Procedures in SQL

There are various types of stored procedures available in SQL, each with its own set of characteristics and use cases. This section will explore SQL’s different types of stored procedures and their unique features.

1. Transact-SQL Stored Procedures

These are stored procedures written using the Transact-SQL language, the standard SQL server language. Transact-SQL stored procedures are the most common type and offer a wide range of functionality, including data retrieval, modification, and complex calculations.

2. Extended Stored Procedures

These are stored procedures written using a language other than Transact-SQL, such as C or C++. Extended stored procedures are used when Transact-SQL is insufficient to meet the database application requirements. For example, extended stored procedures can be used to manipulate the operating system or perform impossible calculations using Transact-SQL alone.

3. System Stored Procedures

These are stored procedures provided by the database management system and are used to perform specific system-level tasks, such as managing security or database configuration. System-stored procedures are typically written in Transact-SQL and are usually hidden from the user, meaning they cannot be modified or deleted.

4. User-Defined Stored Procedures

These are stored procedures that the database administrator or developer creates to meet the specific needs of the database application. User-defined stored procedures can be written in Transact-SQL or another programming language, such as C or C++.

Now, let’s try to understand the most common use cases for stored procedures in SQL. 

Common Use Cases for Stored Procedures in SQL

Stored procedures are an essential part of database management in SQL, and they are used in a wide range of applications to improve efficiency, maintain data integrity, and simplify complex data management tasks. Some of the most common use cases for stored procedures in SQL are outlined below.

1. Data Validation: Data validation with stored procedures becomes easy, even before it is entered into the database. For example, a stored procedure could be used to ensure that a person’s age is between 18 and 100 before their record is saved to the database.

2. Data Retrieval: Stored procedures can also be used to retrieve data from the database. For example, a stored procedure could be used to retrieve all the customer records that match a specific set of criteria, such as customers who have made a purchase in the last 30 days.

3. Data Modification: As with data validation and retrieval, stored procedures also perform perfectly when modifying data in the database. For example, a stored procedure could be used to update the names of all customers who have moved to a new address.

4. Complex Calculations: Complex calculations, as well as challenging data processing, can be made easy using stored procedures. For example, a stored procedure could calculate the average customer order value over the past year.

5. Security: Stored procedures can enforce security and data access control. For example, a stored procedure could restrict access to sensitive data, such as credit card numbers, to only those users with the necessary permissions.

6. Performance Optimisation: Stored procedures improve the performance of database-driven applications by reducing the amount of data that needs to be transmitted between the application and the database. For example, a stored procedure is able to perform data summarisation or aggregation, such as calculating the total sales for each salesperson in a sales organisation.

Conclusion

Stored procedures are essential for managing and manipulating relational databases in SQL. They offer improved performance, reusability, security, and flexibility compared to standard SQL commands. If you’re interested in learning more about SQL and database management, consider enrolling in the DevOps Certification PGC by IIIT-B offered by upGrad. This comprehensive course will provide you with hands-on experience in DevOps practices and techniques and will help you become a certified DevOps professional.