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C20.0046: Database Management Systems Lecture #1 - page 21 / 40

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M.P. Johnson, DBMS, Stern/NYU, Sp2004

21

Data Models

Any DBMS uses a data model: collection of concepts for describing data

Schema: description of partic set of data, using some data model

Relational data model: most widely used (by far) data model

Oracle, DB2, SQLServer, other SQL DBMSs

main concept: relation ~ table of rows & columns

a rel’s schema defines its fields

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