PRIMARY KEY

A PRIMARY KEY is a constraint applied to one or more columns within a table to ensure that each record in the table is uniquely identifiable. It serves as a unique identifier for each row, making it easy to reference and manipulate specific records.

Example

Here's how to define a PRIMARY KEY in the structure of a table:

In this example, the "id" column is defined as the PRIMARY KEY. This means that each record in the "users" table will have a unique "id" value, which can be used to identify and access specific records. A PRIMARY KEY is crucial for ensuring data integrity and enabling efficient data retrieval.

Use of PRIMARY KEY

The PRIMARY KEY constraint has several benefits, including:

• Uniqueness: It enforces the uniqueness of values in the specified column(s), preventing duplicate values;
• Fast Data Retrieval: It allows for quick data retrieval using the primary key, as databases index primary key columns for efficient access;
• Data Integrity: It ensures that each record is uniquely identifiable, helping maintain data integrity.

The use of a PRIMARY KEY is fundamental in the "Create" aspect of CRUD, as it defines how records are uniquely identified within a table, laying the foundation for efficient data management.