Active Record Pattern - Implementations

Implementations

Implementations of the concept can be found in various frameworks for many programming environments. For example, if in a database there is a table parts with columns name (string type) and price (number type), and the Active Record pattern is implemented in the class Part, the pseudo-code

part = new Part part.name = "Sample part" part.price = 123.45 part.save

will create a new row in the parts table with the given values, and is roughly equivalent to the SQL command

INSERT INTO parts (name, price) VALUES ('Sample part', 123.45);

Conversely, the class can be used to query the database:

b = Part.find_first("name", "gearbox")

This will find a new Part object based on the first matching row from the parts table whose name column has the value "gearbox". The SQL command used might be similar to the following, depending on the SQL implementation details of the database:

SELECT * FROM parts WHERE name = 'gearbox' LIMIT 1; -- MySQL or PostgreSQL