The relational model for database management is a method of managing data that employs a structure and language that are consistent with first-order predicate logic. It was first described in 1969 by English computer scientist Edgar F. Codd.

 

What is Relational Model?

Some well-known Relational Database Management Systems are as follows:

Basic Terminologies Used in Relational Model of DBMS

Referential Integrity Constraints
Diagram identiifying Terminologies Used in Relational Model of DBMS
  1. Attribute: Each column in a Table. Attributes are the properties which define a relation. e.g., Student_Rollno, NAME,etc.
  2. Tables – In the Relational model the, relations are saved in the table format. It is stored along with its entities. A table has two properties rows and columns. Rows represent records and columns represent attributes.
  3. Tuple – It is nothing but a single row of a table, which contains a single record.
  4. Relation Schema: A relation schema represents the name of the relation with its attributes.
  5. Degree: The total number of attributes which in the relation is called the degree of the relation.
  6. Cardinality: Total number of rows present in the Table.
  7. Column: The column represents the set of values for a specific attribute.
  8. Relation instance – Relation instance is a finite set of tuples in the RDBMS system. Relation instances never have duplicate tuples.
  9. Relation key – Every row has one, two or multiple attributes, which is called relation key.
  10. Attribute domain – Every attribute has some pre-defined value and scope which is known as the attribute domain

Operations in Relational Model

Four basic update operations performed on relational database model are

Insert, update, delete and select.

Best Practices for creating a Relational Model

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