Relational Model and its concept

Relational Model was proposed by E.F. Codd in the form of relations or tables. After designing the conceptual model of Database using ER diagram, we need to convert the conceptual model into the relational model which can be implemented using Oracle SQL, MySQL etc.
It is the primary data model, which is used to store and processing of data.

This model represents the info as a group of relations. A relation is a table of values. Every row within the table represents a set of related information values. These rows within the table denote a real-world entity.

Concepts of Relational model

Tuple-: It is nothing but a single row of a table that contains one record.

Attribute-: Each and every column in the Table. Attributes are the properties which define a relation. e.g., Student_id, Roll no, NAME, etc.

Tables-: In the relational data model, relations are saved in the format of Tables. A table has rows and columns, wherever rows represent records and columns represent the attributes.

Relation instance-: Relation instance may be a finite set of tuples within the RDBMS system. It never have duplicate tuples.

Relation schema-: A relation schema is used to describe the relation name (table name), attributes, and their names.

Relation key-: Each and every row has one or more attributes, known as relation key, which can identify the row uniquely.

Attribute domain-: each attribute has some pre-defined worth scope, referred to as attribute domain.

Degree-: the quantity of attributes within the relation is known as degree of the relation.

Cardinality-: the quantity of tuples in a relation is understood as cardinality.

Column-: Column represents the set of values for a particular attributes.

Null values-: These are the not known value or inaccessible value known as null values. It is represented by (blank space) null.