What is an instance in DBMS?

DBMSDatabaseBig Data Analytics

The situation where a data or information is stored in the database at a particular moment of time is called an instance. An instance is also called a current state or database state. The database schema that defines variables in tables which belong to a specific database, the records of these variables at a particular moment are called the instance of the database.

Many instances are constructed to correspond to a specific database schema. Every time we can insert, modify, or delete the value of a data item in a record. One state of data can change into another state.

Example

Consider a table given below which has the Student (Schema) −

Std IDNameCity
100LuckyHyderabad
101PinkyDelhi
102BobHyderabad

In the above table, rows are called instances.

Finally, we can say that the content of database at a point of time is called instance or database state.

There are three types of states present in database −

  • Empty state: When ever a new database is defined.

  • Initial state: first time data is loaded in database.

  • Current state: the present operation is applied to database.

The instance of a student relation is −

For example − students ( studentID: string, student_name: string, Login:string, age: integer);

Instance −

studentIDStudent_nameLoginAge
101Bobbob@cse20
105Pinkypink@ece18
107Rosyrose@it20
raja
Published on 03-Jul-2021 09:27:04
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