Python Class 11th CBSE

Q: What is a Database? The collection of data is usually referred to as the DATABASE. The database maintains the information that help to the decision-making process in an organization. The same data in a database may serve many application. e.g.: A database of employees of an organization, Database of students of a school, etc. Database System It is basically a computer based record keeping system. The Relational Data Model In Relational data model, the data is organized into tables ( i.e. rows & cols). These tables are called relations. A row in a table represents a relationship among a set of values. Terminology in RDBMS The different terms used in the relational model are: 1.Relation 2.Tuples 3.Attributes 4.Degree 5.Cardinality 6.Domain 1. Relation A Relation is a table (i.e rows & cols) In above example (STUDENT) is a relation that has 4 rows (records) and 3 columns (fields). 2. Tuples The rows of a relation are gener...