What is a database Subschema?

A sub-schema is a subset of the schema having the same properties that a schema has. It identifies a subset of areas, sets, records and data names defined in the database schema available to user sessions. The sub-schema allows the user to view only that part of the database that is of interest to him.

What is Subschema with example?

Sub schema It gives the users a window through which he/she can view only that part of the database which he wants. For example − Student table in a database the programmer can access all fields of table, but the user can access only two or three fields of it. Subschema describes both views of the database.

What is instance schema and Subschema in DBMS?

Quickly we can summarize the above things, information/data in database at particular moment is known as instance,physical arrangement of data as it appears in database can be defined as schema, and the logical view of data as it appears to the application can be called as sub schema.

Where can a Subschema be used?

Explanation. Answer : Hide sensitive information. A subschema lets the user, have access to different areas of applications in which the user designed. The areas that are included in an application are set, types, record types, data items, and data aggregates.

What is the difference between schema and Subschema?

The schema is a complete description of a database, including the names and descriptions of all areas, records, elements, and sets. The major purpose of the schema is to provide definitions from which to generate subschemas. A subschema provides a view of the database as seen by an application program.

What is the difference between schema and instance?

Schema refers to the overall description of any given database. Instance basically refers to a collection of data and information that the database stores at any particular moment. The schema remains the same for the entire database as a whole.

What is metadata in DBMS?

A meta data is the data about the data. It is the self-describing nature of databases. It holds the information about each data element in the database. Such as names, types, range of values, access authorization, indicate which application program uses the data.

WHAT IS instance and schema?

The data which is stored in the database at a particular moment of time is called an instance of the database. The overall design of a database is called schema. A database schema is the skeleton structure of the database. It represents the logical view of the entire database.

What is Subschema in DBMS Mcq?

Explanation: A subschema expresses the external view. ( External schemas are also called as subschemas)