How to Create Id with AUTO_INCREMENT in SQL Server?

Structured Query Language also known as SQL is a tool for storing, managing, and manipulating relational databases. SQL Server is a popular relational database management system (RDBMS) developed by Microsoft, providing a variety of operators to perform different operations on given datasets.

In this we will explore SQL's AUTO_INCREMENT, exemplifying its usage in tables like Employees, Products, and Customers, ensuring unique identifiers for each record.

AUTO_INCREMENT in SQL Server

The AUTO_INCREAMENT functionality in SQL is used to automatically increase a value for a particular column in the given row. It inserts the next value which is inserted in the last row. This is generally used to manage the serial numbers of the entries in the table or to assign an ID to each row.

It makes the column ideal for the primary key or situations where we need unique identifiers. In this article, we will see how to assign a column as AUTO_INCREAMENT.

Syntax to create an auto-increment column:

CREATE TABLE TableName (
    ColumnName INTEGER PRIMARY KEY AUTOINCREMENT,
    -- Other columns
);

Here ColumnName will be the name of that particular column and the PRIMARY KEY defines that the given column is the primary key of the table. The keyword AUTOINCREMENT will declare the column as incrementing automatically. We will perform the following steps to implement this.

• Declare the table structure.
• In structure declare a column as Primary Key and Auto Increment.
• Insert the data into the table.
• Print the table.

Examples of AUTO_INCREMENT in SQL Server

Example 1: Employees table with EmployeeID is auto increment

CREATE TABLE Employees (
    EmployeeID INTEGER PRIMARY KEY AUTOINCREMENT,
    FirstName VARCHAR(50),
    LastName VARCHAR(50)
);

Now we will insert the data into this table.

INSERT INTO Employees (FirstName, LastName)
VALUES 
    ('John', 'Doe'),
    ('Jane', 'Smith'),
    ('Michael', 'Johnson'),
    ('Emily', 'Davis');

When we insert this values they will get inserted into the table with the employee id.

Output:

Explanation: The provided SQL script is not valid for SQL Server. However, assuming it's meant for a database system like SQLite, the AUTOINCREMENT keyword automatically generates unique values for the EmployeeID column, ensuring each record has a distinct identifier.

Example 2: Products table with ProductID as Auto Increment

CREATE TABLE Products (
    ProductID INTEGER PRIMARY KEY AUTOINCREMENT,
    ProductName VARCHAR(50),
    Price DECIMAL(10, 2),
    StockQuantity INT
);

Now we will insert the data into this table.

INSERT INTO Products (ProductName, Price, StockQuantity)
VALUES 
    ('Smartphone', 699.99, 100),
    ('Laptop', 1299.99, 50),
    ('Headphones', 99.99, 200),
    ('Smart Watch', 249.99, 150);

When we insert this values they will get inserted into the table with the product id.

Output:

Explanation: The provided SQL script creates a Products table with a primary key ProductID set to AUTOINCREMENT. The subsequent INSERT statements add records with unique ProductID values automatically generated by the system, ensuring each product entry has a distinct identifier.

In the resulting table ProductName, Price, and StockQuantity are added with Sequential ProductID.

Example 3: Customer table with CustomerID as Auto Increment

CREATE TABLE Customers (
    CustomerID INTEGER PRIMARY KEY AUTOINCREMENT,
    FirstName VARCHAR(50),
    LastName VARCHAR(50),
    Email VARCHAR(100),
    Phone VARCHAR(20)
);

Now we will insert the data into this table.

INSERT INTO Customers (FirstName, LastName, Email, Phone)
VALUES 
    ('Alice', 'Smith', '[email protected]', '123-456-7890'),
    ('Bob', 'Johnson', '[email protected]', '234-567-8901'),
    ('Charlie', 'Davis', '[email protected]', '345-678-9012'),
    ('David', 'Brown', '[email protected]', '456-789-0123');

When we insert this values they will get inserted into the table with the customer id.

Output:

Explanation: The provided SQL script creates a Customers table with a primary key CustomerID set to AUTOINCREMENT. The subsequent INSERT statements add records with unique CustomerID values automatically generated by the system, ensuring each customer entry has a distinct identifier.

In the resulting table FistName, LastName, Email, and Phone are added with sequential CustomerID.

Conclusion

Structured Query Language also known as SQL is a tool for storing, managing, and manipulating relational databases. SQL is a relational database used to store structured data. SQL uses commands to perform CRUD operations on the database tables. One of such command is AUTO_INCREAMENT which is a functionality used to automatically increase a value for a particular column in the given row. It is mostly used where we are inserting some data and want to assign a unique number or a unique id to each row in the table. It is useful in many places like managing employee data, product data, and user data.