Sunday, 11 February 2018

Define database instance

Database Instance and Schema


Instance: Collection of data stored in the database at a particular moment is called an Instance of the database.

For example, if we execute the following SQL query the result produced is one instance;

SELECT * FROM Student;
Schema: The overall design of the database is called the database Schema. In other words, it is the entity sets and attributes.

For example, the following representation is called as schema.

STUDENT (RegNo, Name, DOB, Gender, Phone)

In some representation, the schema sometimes shown with the type and size of attribtues.  

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Define database instance
Define database schema
What is database instance?
What is schema?
Example of database schema
Example of database instance

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