The Relational Model of data management was first developed by Dr. Edgar F. Codd in 1969. Modern relational database management systems (RDBMSes) are aligned with the paradigm. The key structure identified with RDBMS is the logical structure called a “table”. Tables are primarily composed of rows and columns (also called records and attributes or tuples and fields). In a strict mathematical sense, the term table is actually referred to as a relation and accounts for the term “Relational Model”. In mathematics, a relation is a representation of a set.
The expression attribute gives a good description of the purpose of a column – it characterizes the set of rows associated with it. Each column must be of a particular data type and each row must have some unique identifying characteristics called “keys”. Data change is typically more efficient when done using the relational model while data retrieval may be faster with the older Hierarchical Model which has been redefined in model NoSQL systems. Read More