Data Manipulation Language (DML) Explained

Key Concepts

• INSERT Statement
• UPDATE Statement
• DELETE Statement

INSERT Statement

The INSERT statement is used to add new records into a table. It allows you to specify the values for each column in the new record. The basic syntax is:

        INSERT INTO table_name (column1, column2, column3, ...)
        VALUES (value1, value2, value3, ...);
    

Example: To add a new customer with the name "John Doe" and email "john.doe@example.com" into the "Customers" table, you would use:

        INSERT INTO Customers (Name, Email)
        VALUES ('John Doe', 'john.doe@example.com');
    

Analogies: Think of the INSERT statement as adding a new entry to a guest list or a new item to a shopping cart.

UPDATE Statement

The UPDATE statement is used to modify existing records in a table. It allows you to change the values of one or more columns based on specified conditions. The basic syntax is:

        UPDATE table_name
        SET column1 = value1, column2 = value2, ...
        WHERE condition;
    

Example: To update the email address of a customer with the name "John Doe" in the "Customers" table, you would use:

        UPDATE Customers
        SET Email = 'john.doe.new@example.com'
        WHERE Name = 'John Doe';
    

Analogies: The UPDATE statement is like editing an existing entry in a contact list or updating the details of a product in an inventory.

DELETE Statement

The DELETE statement is used to remove existing records from a table. It allows you to delete one or more rows based on specified conditions. The basic syntax is:

        DELETE FROM table_name
        WHERE condition;
    

Example: To delete a customer with the name "John Doe" from the "Customers" table, you would use:

        DELETE FROM Customers
        WHERE Name = 'John Doe';
    

Analogies: The DELETE statement is like removing an entry from a guest list or deleting an item from a shopping cart.