Describe the three-schema architecture. Why do we need mappings among schema levels?

Expert Solution

Answer-

Three-schema architecture-

internal schema
conceptual schema
External schema

1. Internal schema-

It has internal stage to identify physical storage device knowledges and retrieve paths and typically applies a physical information model.

2. conceptual schema

It has conceptual stage to identify the structure and constraints for the conception database for a gathering of users and consumes a conceptual an enforcement data model.

External schema

It has external level to inform the different user surveys usually practices the same data point model as the conceptual schema.

Need mappings among schema levels-

It is call for to transform requests and data
They are mapped by the DATABASE MANAGEMENT SYSTEM to the internal schema for implementation.
Data obtained from the internal DATABASE MANAGEMENT SYSTEM stage is reformatted to supply the user external view.

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venereology answered 1 year ago

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