Object Relational Mapping (ORM)

(ORM) is a technique that lets you query and manipulate data from a database using an object-oriented paradigm

An ORM library is a completely ordinary library written in your language of choice that encapsulates the code needed to manipulate the data, so you don't use SQL anymore; you interact directly with an object in the same language you're using

E.G.

book_list = new List();

sql = "SELECT book FROM library WHERE author = 'Linus'";

data = query(sql); // I over simplify ...

while (row = data.next())

{

     book = new Book();

     book.setAuthor(row.get('author');

     book_list.add(book);

}

With an ORM library, it would look like this:

book_list = BookTable.query(author="Linus");

Disadvantage of ORM

·         ORM libraries are not lightweight tools;

·         Performance is OK for usual queries, but a SQL master will always do better with his own SQL for big projects.

Example of ORM

Entity Framework