In this post we will discuss the basics of model mappings in Django for One to One, One to Many and Many to Many relationships. Before we proceed, lets try to quickly refresh basic relational database concepts. Relational Database Table : A relational database consists of one or more table(s) with each table having rows and columns. Think of table as a grid with column(s) going from left to right and the rows representing the data. Columns are defined to hold a specific type of data, for example, dates, numeric, strings etc. A table can contain zero or more rows while if the rows are zero, table is said to be empty. Example would be a table of employees in a company. Primary Key : A Primary Key is the combination of one or more columns, whose data is used to uniquely identify the rows in the table. It acts like an address used to identify the homes for postal delivery. If there are more columns are used to represent the primary key, then the combination of data in these col