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Difference Between Stored Procedure and Function in SQL Server

DBA professions prefer using Stored Procedures over SQL Injections and Functions in SQL Server. It is a common debate among database programmers, which is good programming practice and how are they different. To answer these questions, we have this blog for you -  Stored Procedure vs. Function in SQL Server. Before we jump to the differences directly, it is necessary to learn the basic concepts like stored procedures, functions, their advantages, basic syntax, etc. Let us start our discussion with the overview first.

Stored Procedure vs. Function - Overview

A quick introduction to Stored Procedure

It is a group of SQL statements used together to compute a logic. The biggest advantage of designing a stored procedure is that it can be used by multiple programs or apps at once wherever you want to add the same logic. In this way, you don’t have to write the same code again and it will save your overall time and effort too.

Logically, there are several input variables are added within a stored procedure that can be accessed by different clients over the network and inputs are added as per the requirement. The other highlighting feature of the stored procedure is that it helps in reducing the network traffic and optimizes the overall performance as required.

As soon as changes are made to a stored procedure, it will impact all related apps or programs that are associated with that stored program. You just have to put values according to your application requirement and it will start behaving in the same way.

A Quick Introduction to Functions

A function is a subprogram that can be used multiple times throughout database apps for manipulating or processing the data. Each database program has a set of in-built functions that can be utilized as needed. On the other side, you have the opportunity of creating the customized code for different programs.

These customized functions are defined by users, so named as user-defined functions and helps in computing tough logic or calculations. in this way, if there is a program logic that you want to utilize multiple times then functions can be the best choice here.

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Stored Procedure vs. Function – Benefits

Benefits of Stored Procedures

  • Reduced: Stored procedures have to be executed only once and the execution code can be used again later. In this way, it impacts the final performance when you have to call the same procedure multiple times within a database application.
  • Programming: It helps in cutting down the size of the code and it can be transmitted over the network quickly. Ultimately, the network traffic will reduce significantly.
  • Effective: The best thing is that one stored procedure can be accessed by multiple users at once. It results in reduced development cycle and enhances the performance.
  • Enhanced: Every time when you are executing a stored procedure, certain permissions can be defined that enhances the security controls.

Benefits of Function in SQL Server

  • Modular Programming: Functions allow modular programming where it is generated once and called multiple times during programming.
  • Faster Execution: Every time a function is called, the execution code is saved in the cache that helps in faster execution of function when it is called again.
  • Reduced Network Traffic: A function utilizes WHERE clause for reducing the overall size of the code that ultimately results in enhanced network performance.

Stored Procedure vs. Function – Types

Types of Stored Procedures

SQL Server divides the stored procedure into three major categories. Let us discuss each of them one by one:

  1. System-defined SPs: They are defined by the system and it starts with the prefix “sp” mostly. It can be used to complete a variety of SQL tasks.
  2. User-defined SPs: They are stored within a user database and created to perform a specific action. Here the prefix is different.
  3. Extended SPs: They are calling functions from DLL files. Developers don’t rely on these procedures. So, it is better to avoid them and focus on the other two.

Types of Functions in SQL Server

There are two types of Functions in SQL Server, Built-in Function and User-defined Functions. Let us discuss them in brief below.

1). Built-in SQL Functions

These are defined in advance and invoked when you are installing the SQL Server. They can be either be scalar, aggregate, or numeric, etc. Each function returns some value. How can you use them within your database programs, it completely depends on the choice of programmers.

2). User-defined SQL functions

These functions are defined by the user and designed to perform a specific action for a database app. Here are a few highlighted benefits for the same.

  1. User-defined Functions allow modular programming where it is generated once and called multiple times during programming.
  2. Every time a user-defined function is called, the execution code is saved in the cache that helps in faster execution of function when it is called again.
  3. A user-defined function utilizes WHERE clause for reducing the overall size of the code that ultimately results in enhanced network performance

Stored Procedure vs. Function - How To?

How to create a Stored Procedure?

We have already discussed the Stored Procedure and its benefits. it is the right time to start with little technical practice, so we will learn how to create a stored procedure in this section.

The basic syntax is easy and here is a quick example for your reference.

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CREATE PROCEDURE <owner>.<procedure name>
<param> <datatype>

It is just the basic syntax. Let us make it a little interesting by putting values to it.

@login nvarchar(30)=null
SELECT * From [Users]
WHERE ISNULL(@login,login) =login

The biggest reason why a SP is used by programmers is that they have to make changes to a single location and impact will reflect everywhere where that SP is invoked. it is good in terms of security controls where programmers can define permission sets as required. in this way, it is right that SP is an excellent programming practice in comparison to SQL Injections.

How to Create a Function?

To function can be created using the CREATE keyword in the SQL Server. The basic syntax of an SQL function can be given as:

Create [or replace] function fuction_name
[(parameter_name [IN | OUT | IN OUT] type [, ...])]
RETURN returen_datatype
{IS | AS}
END [function_name];

Here, you have to give the name of the function and REPLACE keyword is optional that should be used if you want to modify an existing function. The list of optional parameters contains type, name, and the mode of parameters. Each function should have at least one return statement. The functional body contains the executable part of the program.

Before you call a function, you must check the objective of that particular function. To use a function within a program, you should call it to perform a particular task. When a function is called by the program, then the control of that program is shifted to the calling function. It is similar to subprograms, and when a subprogram calls another subprogram, it is named as the recursive function.

Stored Procedure vs. Function: What are the Differences?

Stored Procedure vs. Function: What are the Differences?

Read: Advanced SQL Server Interview Questions and Answers

Final Words:

The blog gives you a depth idea of stored procedures and functions in SQL Server. You now know how they are different, and which can be used as per your programming needs. I would suggest using stored procedures over functions as a good programming practice.

You can see yourself they are more secure with enhanced database features when compared to Function. If you are still not sure, then join the SQL Server Certification Course at JanBask Training and analyze the difference yourself.

Also, master the necessary SQL Server concepts from basic to advanced level that can help you in acquiring the best job at a huge salary package. All the best for a successful career in SQL Server space with JanBask Training. We help you grow in the IT domain like never before and showcase your skills to the employer in the best way by getting certified with us.

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