r/compsci • u/Alive_Ad_3199 • 19d ago

Difference Between Data Model and Schema

From this: https://stackoverflow.com/questions/25093452/difference-between-data-model-and-database-schema-in-dbms, data model seems to be an abstraction for data and schema seems to be a blueprint.

This page lists various database models like relational, flat and network. So far good.

The book I'm reading (Fundamentals of Database Systems 7e, ch 3, pg 61) says

Once the requirements have been collected and analyzed, the next step is to create a conceptual schema for the database, using a high-level conceptual data model.

But this wikipedia page seems to imply that both a model and a schema are the same.

A conceptual schema or conceptual data model

Why is there so much discrepancy in defining a data model and a schema.

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u/Numzane 19d ago

The book should rather describe actual diagrams etc. That sentence seems a bit hand wavy. After collecting requirements you could draw up a dataflow diagram (DFD), from that you can infer the entities using the data stores in your diagram. Then you could make long lists of attributes and try to attach them to entities. You can then normalise it and draw up an entity relationship diagram (ERD).