An introduction to RDBMS and SQL

There are various ways to arrange and manage data in a database. The most common is to arrange the data in tables, which is similar to an Excel file. The table contains multiple columns and rows.

A Database is a collection of related data. But a question still remains unanswered — how do you access this data? The answer is a specific language designed for this purpose, called the Structured Query Language, or SQL.

Concepts

Tables − In relational data model, relations are saved in the format of Tables. This format stores the relation among entities. A table has rows and columns, where rows represents records and columns represent the attributes.

Tuple − A single row of a table, which contains a single record for that relation is called a tuple.

Relation instance − A finite set of tuples in the relational database system represents relation instance. Relation instances do not have duplicate tuples.