What needs to be modified to ensure data independence of the database?

What needs to be modified to ensure the data independence of the database?

To ensure the data independence of the database, what needs to be modified is the mapping between the schema and the internal schema.

DBMS provides two layers of images: external schema/schema image and schema/internal schema image. The mapping from the external schema to the schema ensures the logical independence of the data, and the mapping from the schema to the internal schema ensures the physical independence of the data.

Knowledge expansion:

The independence of data is one of the most basic characteristics of the database system.

Data independence means that the application and the data structure are independent of each other and do not affect each other.

In the three-tier schema architecture, data independence refers to the ability of the database system to change the schema at a certain level without changing the schema at the upper level.

It is the two-layer image between the three-level modes that ensures that the data in the database system has high data independence.

Data independence includes data logical independence and data physical independence.

Recommended tutorial: "sql video tutorial"

The above is the detailed content of What needs to be modified to ensure data independence of the database?. For more information, please follow other related articles on the PHP Chinese website!