The BIT data type in SQL is used to store binary data, specifically representing the values of true or false, on or off, or 1 or 0. It is commonly used to store boolean values in a database table.
The syntax for defining a column with the BIT data type in SQL is as follows:
A column defined as BIT can hold three possible values:
- 0: Represents false, off, or no.
- 1: Represents true, on, or yes.
- NULL: Represents an unknown or undefined value.
To better understand how the BIT data type works, let’s consider a few examples:
Create Table Statement:
CREATE TABLE users ( id INT PRIMARY KEY, name VARCHAR(100), active BIT );
In this example, we have created a table named ‘users’ with three columns: ‘id’, ‘name’, and ‘active’. The ‘active’ column is defined as BIT, which means it can hold either true (1) or false (0) values.
INSERT INTO users (id, name, active) VALUES (1, 'John Doe', 1);
In this example, we are inserting a new row into the ‘users’ table. The ‘active’ column is set to true (1) for the user with an ID of 1.
UPDATE users SET active = 0 WHERE id = 1;
In this example, we are updating the ‘active’ column value to false (0) for the user with an ID of 1.
The BIT data type in SQL is a useful way to store boolean values. It allows for efficient storage and retrieval of binary data, representing true or false values. By understanding how to define and use the BIT data type, you can effectively store and manipulate boolean information in your database tables.