Is there a dedicated boolean data type in SQLite?

SQLite and Boolean Values

• Instead, it employs integers to represent boolean data:
  • 0 signifies false.
• SQLite, a popular lightweight database engine, doesn't have a distinct data type specifically for boolean values (true/false).

Boolean Literals

• Since SQLite interprets integers for boolean values, boolean literals in this context would be integer literals (0 or 1).
  • You could write 0 to represent false or 1 to represent true.
• In programming, literals are fixed values directly included in the code.

Alternative for Modern SQLite (Version 3.23.0 and Later)

• As of version 3.23.0 (released in April 2018), SQLite introduced keywords for boolean literals:
  • TRUE represents true.
  • FALSE represents false.

Key Points

• Integer literals (0 and 1) still work perfectly for representing boolean data.
• While technically not separate boolean literals, TRUE and FALSE keywords offer a more readable way to express boolean values in your SQLite queries (especially if you're coming from other SQL databases that have dedicated boolean data types).

Example

-- Using integer literals (traditional way)
SELECT * FROM table_name WHERE is_active = 1;  -- Selects rows where is_active is true (1)

-- Using keywords (modern SQLite)
SELECT * FROM table_name WHERE is_active = TRUE;  -- Same result, but more explicit

Traditional Method (Integer Literals):

-- Create a table with a boolean column (represented by integer)
CREATE TABLE users (
  id INTEGER PRIMARY KEY,
  is_admin INTEGER DEFAULT 0  -- Default value is false (0)
);

-- Insert data with both true and false values
INSERT INTO users (is_admin) VALUES (1), (0);

-- Select users based on boolean condition
SELECT * FROM users WHERE is_admin = 1;  -- Selects users with admin privileges (is_admin is true/1)
SELECT * FROM users WHERE is_admin = 0;  -- Selects non-admin users (is_admin is false/0)

Modern Method (Boolean Keywords - SQLite 3.23.0 and Later):

-- Create a table (same structure)
CREATE TABLE users (
  id INTEGER PRIMARY KEY,
  is_admin INTEGER DEFAULT 0
);

-- Insert data (same)
INSERT INTO users (is_admin) VALUES (1), (0);

-- Select users using boolean keywords
SELECT * FROM users WHERE is_admin = TRUE;  -- Selects users with admin privileges
SELECT * FROM users WHERE is_admin = FALSE;  -- Selects non-admin users

1. Custom Functions (for Specific Needs):

   If you have a specific use case where integer literals (0/1) or even the keywords (TRUE/FALSE) don't quite fit your needs, you can create a custom function in SQLite. This function could take an argument and return 0 or 1 based on your logic.

   Here's a basic example:

   CREATE FUNCTION is_enabled(value TEXT) RETURNS INTEGER AS $$
   BEGIN
     IF value = 'on' THEN
       RETURN 1;  -- Treat 'on' as true
     ELSE
       RETURN 0;  -- Treat anything else as false
     END IF;
   END;
   $$ LANGUAGE plpgsql;  -- Adjust language based on your SQLite environment
   
   SELECT * FROM table_name WHERE is_enabled(status_column) = 1;
   

   This example defines a function is_enabled that checks if the provided value is "on" (treated as true) and returns 1. Otherwise, it returns 0 (false).

2. Enum Data Type (SQLite 3.35.0 and Later):

   If you're using a more recent version of SQLite (3.35.0 and above), you can leverage the ENUM data type. This allows you to define a set of allowed values for a column, which could include options like "true" and "false" for boolean representation.

   CREATE TABLE settings (
     id INTEGER PRIMARY KEY,
     is_active ENUM('true', 'false') DEFAULT 'false'
   );
   
   -- Insert data with 'true' or 'false' values
   INSERT INTO settings (is_active) VALUES ('true'), ('false');
   
   SELECT * FROM settings WHERE is_active = 'true';
   

   Note: Using custom functions or enums might introduce some overhead compared to simple integer literals or keywords. Choose the approach that best suits your specific requirements and database version.