Primary Key Constraint In SQL Server

What is the primary key in SQL Server?

In SQL Server, a  Primary Key  is a field or column which uniquely identifies each and every record in a table.

    • A primary key column doesn’t allow to insert  null  or duplicate values.
    • A Primary key can consist of up to 16 columns.
    • A table can have only one primary key which can be applied on single or multiple columns.
    • The primary key consist of multiple columns or fields is known as the Composite primary key.
    • A Primary Key constraint can be applied to the columns having any data types.
    • A primary key by default creates a clustered index on the column.

A primary key can be created at the column or table level.

Primary Key Constraint  in SQL Server
Primary Key Constraint in SQL Server

Syntax to create a primary key

The following are the syntax to create a primary key in SQL server.

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Stored Procedure in SQL Server With Examples

What Is a Stored Procedure In SQL Server?

 Stored Procedure : A stored procedure in SQL Server is a precompiled collection of SQL statements that get cached and stored in the database in order to reused over and over again whenever required.

Advantage of using Stored Procedure

    • A stored procedure (SP) provides the reusability of SQL code as we can simply call the stored procedure Instead of writing the same SQL statements over and over again.
    • It allows reducing the network traffic by executing the SQL statements at the server-side rather than sending hundreds lines of SQL queries over the network.
    • A stored procedure can be used as a security mechanism by granting a user to execute only the stored procedure instead of allowing permission on the table.
    • It allows faster execution of SQL statements in order to enhance the performance.

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CREATE, ALTER, AND DROP DATABASE IN SQL SERVER

In this article, we will discuss how to Create, Alter, and Drop a database in SQL Server.
In my previous article, we have discussed all about the Types of SQL Commands.

Database Introduction

 Database  : In the SQL server a database is a place to store the data in an electronic format. It is an organized collection of database objects such as tables, views, functions, stored procedures, triggers and so on.
It allows a user to easily access or manipulate the data.

SQL server database

Create Database In SQL Server

In SQL Server, there are two ways to create a user-defined database, either by using the Transact-SQL statements or by using SQL Server Management Studio.

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What is SQL Server – Types of SQL Commands

SQL Commands

What is SQL?

 SQL  stands for Structured Query Language. SQL is a language used to store, retrieve, and manipulate data in a Relational Database Management Systems (RDMS)
such as SQL Server, Oracle, MySQL, etc.
SQL allows a user to communicate with the database using commands.

Features of SQL

    • SQL is used to create, truncate, and drop the database and table using SQL commands.
    • SQL can be used to execute the queries against the database to perform various operations.
    • SQL is used to create a function, stored procedure, trigger and view in a database.
    • It provides security and allows a users to set permissions on the tables, stored procedures, and views in the database.

What is a Database?

A database is a place to store the data in an electronic format. It is an organized collection of database objects such as tables, views, functions, stored procedures, triggers, and so on.
It allows a user to easily access or manipulate the data.

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