How to create FOREIGN KEY Constraint in Sql server

How to create FOREIGN KEY Constraint in Sql server A FOREIGN KEY in any table points to a PRIMARY KEY in another table. Let us Create a table Hightech:- Hightech table: Id FirstName City 1 Jai Delhi 2 Om Kolkata 3 Hari Haryana Here In table hightech Id is Primary Key of table Hightech The

How to create PRIMARY KEY constraints In Sql server

Primary Key Constraints The PRIMARY KEY constraint uniquely identifies record in a database table. Primary key column cannot have NULL values. Query:- The below following query a primary key in id column. create table account3 ( id int primary key, Firstname varchar(50), Lastname varchar(50) ) To create a PRIMARY KEY on a already created table

How to create UNIQUE constraints In Sql server

The UNIQUE constraint uniquely identifies each record in a database table. The UNIQUE constraints provide a guarantee for uniqueness for a column or set of columns. Query:- CREATE TABLE ACCOUNT2 ( P_Id int NOT NULL UNIQUE, LastName varchar(50) NOT NULL, FirstName varchar(50), Address varchar(255) ) To create a UNIQUE constraints in already created table use

How to create NOT NULL constraints In Sql server

Constraints are used to limit the type of data that can go into a table. SQL NOT NULL Constraint:- The NOT NULL constraint enforces a column to NOT accept NULL values. Query:- CREATE TABLE Account ( P_Id int NOT NULL, LastName varchar(50) NOT NULL, FirstName varchar(50) ) In this query Id and Lastname is NOT NULL

What are Constraints

What are Constraints:- Constraints are an ANSI-standard method of enforcing data integrity. Constraints ensure valid data values are entered in columns and that the relationships between tables should be maintained. Integrity Type Constraint type Target Description Domain DEFAULT Column Specifies the default value for the column when INSERT statement does not provide a value. CHECK Column Specifies

What is Data Integrity in Sql server and its types

What is Data Integrity in Sql server and its types An important part in database designing and planning is deciding way to enforce the integrity of the data. Data integrity refers to the consistency and accuracy of data that is stored in your database.Enforcing data integrity ensures the quality of the data in your database.