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What is external schema?

Updated: 10/31/2022
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The role of the external schema is to support user views of data and thus to provide programmers with easier data access

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Q: What is external schema?
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Which schema is called the view of a manager or other type of user?

external schema


How do different schema definition languages support the three schema architecture?

The three schema approach is used to build informational systems. The schema involves three different levels, which are the physical level, the conceptual level, and the external level.


What are the 3 views of dbms?

A Database has three views. The External Schema: What the end user sees. The Internal Schema: What the programmers of the program see. The Conceptual Schema: The basic plan of the database. Most of the time this is in paper form as a Conceptual Schema Diagram (CSD)


Discuss the basic differences between external schema conceptual schema and internal schema?

The internal schema describes how the data will be physically stored and accessed, using the facilities provided by a particular DBMS. For example, the data might be organized so that all the insurance policies belonging to a given customer were stored close together, allowing them all to be retrieved into the computer's memory in a single operation. The conceptual schema (sometimes called the logical schema) describes the stored data in terms of the data model of the DBMS. In a relational DBMS, the conceptual schema describes all relations that are stored in the database The external schemasspecify views that enable different users of the data to see it in different ways. As a simple example, some users of policy data might not require details of the commission paid. By providing them with a view that excludes the Commission Rate column, we would not only shield them from unwanted (and perhaps unauthorized) information, but also insulate them from changes that might be made to the format of that data.by:mohammed abu Lamdy


What is dbms architecture?

1. External view : this is a highest level of abstraction as seen by user. This level of abstraction describes only the part of entry database. It is based on the conceptual model, is the end user view of data environment. Each external view described by means of a schema called an external schema or subschema. The external schema consists of the definition of the logical records and the relationships in the external view. The external schema also contains he method of deriving the objects in the external view from the objects in the conceptual view. The object include entities, attributes and relationships.2. Conceptual level : at this level of database abstraction all the database entities and the relationships among them are included. One conceptual view represents the entire database. the conceptual schema defines ths conceptual view. It there is only one conceptual schema per database. This schema also contains the method deriving from the objects in the conceptual view from the objects in the internal view.. at this level a database is described logically rather then physically in term of data structure.3. Internal(physical) level : this lowest level of abstraction. it closest to physical storage device. It describes how data are actually stored on the storage medium. The internal schema, which contains the definition of the stored record, the method representing the data fields, expresses the internal view and the access aids used.


2.5 What is the difference between logical data independence and physical data independence?

The logical data independence is the ability to modify a logical schema without making external view or application program change. The physical data independence is the ability to modify a physical schema without making external view or application prrogram change.


What Logical data independence and physical data independence?

Logical Data Independence : The ability to change the logical schema without changing the external schema or application programs is called as Logical Data Independence.Physical Data Independence : The ability to change the physical schema without changing the logical schema is called as Physical Data Independence.Logical Data Independence :being able to maintain change at external layer without having to make any change at the concept.Physical Data Independence : we want to be able to make any change on the conceptual level to deal without any change at the physical


What is star flake schema?

A starflake schema is a combination of a star schema and a snowflake schema. Starflake schemas are snowflake schemas where only some of the dimension tables have been denormalized. hardkingofflirt@gmail.com


What is the difference between logical and physical data independence?

The logical data independence is the ability to modify a logical schema without making external view or application program change. The physical data independence is the ability to modify a physical schema without making external view or application prrogram change.


What is schema and sub-schema?

The schema is the physical arrangement of the data as it appears in the DBMS. The subschema is the logical view of the data as it appears to the application program.


Explain the three schema architecture of DBMS?

Physical schema,logical schema and sub schemas


What is logical data independence and why is it important?

Logical data independence refers to the key feature of database management system that helps maintain data integrity and the overall effectiveness of the data usage. It is very important as it allows for the modification of the conceptual schema without disturbing the external schema.