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Database Programming

What is a database schema?


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March 16, 2008 9:40PM

A database schema is described in a formal language supported by the database management system (DBMS). In a relational database, the schema defines the tables, the fields in each table, and the relationships between fields and tables. Schemas are generally stored in a data dictionary. Although a schema is defined in text database language, the term is often used to refer to a graphical depiction of the database structure Levels of database schema

1. Conceptual schema, a map of concepts and their relationships 2. Logical schema, a map of entities and their attributes and relations 3. Physical schema, a particular implementation of a logical schema 4. Schema object, Oracle database object 5. Schema is the over all structure of the database