Software Development

SQLAlchemy Object Relational Mapper (ORM) State Management

Object-Relational Mapping (ORM) is a technique that lets you query and manipulate data from a database using an object-oriented paradigm. When talking about ORM, most people are referring to a library that implements the Object-Relational Mapping technique, hence the phrase “an ORM”. An ORM library is a completely ordinary library written in your language of choice that encapsulates […]
Steve Biko
SQLAlchemy Object Relational Mapper (ORM) State Management

Object-Relational Mapping (ORM) is a technique that lets you query and manipulate data from a database using an object-oriented paradigm. When talking about ORM, most people are referring to a library that implements the Object-Relational Mapping technique, hence the phrase “an ORM”.

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.

For example, here is a completely imaginary case with a pseudo language:

You have a book class, you want to retrieve all the books of which the author is “biko”. Manually, you would do something like that:

book_list = new List();
sql = "SELECT book FROM library WHERE author = 'biko'";
data = query(sql); // I over simplify ...
while (row = data.next())
{
     book = new Book();
     book.setAuthor(row.get('author');
     book_list.add(book);
}

SQLAlchemy

SQLAlchemy is the Python SQL toolkit and Object Relational Mapper