Physical vs. Logical Levels

External Schema 1

External Schema 2

Relational Schema

Physical Schema

Disk

• Conceptual schema: tables and their

attributes

• Physical schema: files, indexes

hash tables.

• External schema: views of the different

applications, classes of users.

System catalog: The component of the database that stores meta data.

Conceptual design: a precursor to the relational schema.

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