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Learning PostgreSQL 11 - Third Edition
book

Learning PostgreSQL 11 - Third Edition

by Christopher Travers, Andrey Volkov
January 2019
Beginner
556 pages
14h 19m
English
Packt Publishing
Content preview from Learning PostgreSQL 11 - Third Edition

User-defined data types

PostgreSQL provides two methods to implement user-defined data types, via the following commands:

  • CREATE DOMAIN: The CREATE DOMAIN command allows developers to create a user-defined data type with constraints. This helps to make the source code more modular.
  • CREATE TYPE: The CREATE TYPE command is often used to create a composite type, which is useful in procedural languages, and is used as the return data type. Also, we can use the CREATE TYPE to create the ENUM type, which is useful to decrease the number of joins, specifically for lookup tables.

Often, developers decide not to use user-defined data types and to use flat tables instead, due to a lack of support on the driver side, such as JDBC and ODBC. Nonetheless, ...

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Publisher Resources

ISBN: 9781789535464