Follow Techotopia on Twitter

On-line Guides
All Guides
eBook Store
iOS / Android
Linux for Beginners
Office Productivity
Linux Installation
Linux Security
Linux Utilities
Linux Virtualization
Linux Kernel
System/Network Admin
Programming
Scripting Languages
Development Tools
Web Development
GUI Toolkits/Desktop
Databases
Mail Systems
openSolaris
Eclipse Documentation
Techotopia.com
Virtuatopia.com

How To Guides
Virtualization
General System Admin
Linux Security
Linux Filesystems
Web Servers
Graphics & Desktop
PC Hardware
Windows
Problem Solutions

  




 

 

Chapter 42. System Catalogs

The system catalogs are the place where a relational database management system stores schema metadata, such as information about tables and columns, and internal bookkeeping information. PostgreSQL's system catalogs are regular tables. You can drop and recreate the tables, add columns, insert and update values, and severely mess up your system that way. Normally, one should not change the system catalogs by hand, there are always SQL commands to do that. (For example, CREATE DATABASE inserts a row into the pg_database catalog — and actually creates the database on disk.) There are some exceptions for particularly esoteric operations, such as adding index access methods.

42.1. Overview

Table 42-1 lists the system catalogs. More detailed documentation of each catalog follows below.

Most system catalogs are copied from the template database during database creation and are thereafter database-specific. A few catalogs are physically shared across all databases in a cluster; these are noted in the descriptions of the individual catalogs.

Table 42-1. System Catalogs

Catalog Name Purpose
pg_aggregate aggregate functions
pg_am index access methods
pg_amop access method operators
pg_amproc access method support procedures
pg_attrdef column default values
pg_attribute table columns ("attributes")
pg_authid authorization identifiers (roles)
pg_auth_members authorization identifier membership relationships
pg_autovacuum per-relation autovacuum configuration parameters
pg_cast casts (data type conversions)
pg_class tables, indexes, sequences, views ("relations")
pg_constraint check constraints, unique constraints, primary key constraints, foreign key constraints
pg_conversion encoding conversion information
pg_database databases within this database cluster
pg_depend dependencies between database objects
pg_description descriptions or comments on database objects
pg_index additional index information
pg_inherits table inheritance hierarchy
pg_language languages for writing functions
pg_largeobject large objects
pg_listener asynchronous notification support
pg_namespace schemas
pg_opclass index access method operator classes
pg_operator operators
pg_pltemplate template data for procedural languages
pg_proc functions and procedures
pg_rewrite query rewrite rules
pg_shdepend dependencies on shared objects
pg_statistic planner statistics
pg_tablespace tablespaces within this database cluster
pg_trigger triggers
pg_type data types

 
 
  Published courtesy of The PostgreSQL Global Development Group Design by Interspire