NameDECLARE -- define a cursor Synopsis DECLARE name [ BINARY ] [ INSENSITIVE ] [ [ NO ] SCROLL ] CURSOR [ { WITH | WITHOUT } HOLD ] FOR query Description DECLARE allows a user to create cursors, which can be used to retrieve a small number of rows at a time out of a larger query. After the cursor is created, rows are fetched from it using FETCH. Note: This page describes usage of cursors at the SQL command level. If you are trying to use cursors inside a PL/pgSQL function, the

As shown in the previous section, the table expression in the SELECT command constructs an intermediate virtual table by possibly combining tables, views, eliminating rows, grouping, etc. This table is finally passed on to processing by the select list. The select list determines which columns of the intermediate table are actually output. 7.3.1. Select-List Items The simplest kind of select list is * which emits all columns that the table expression produces. Otherwise, a select list is a com

A table expression computes a table. The table expression contains a FROM clause that is optionally followed by WHERE, GROUP BY, and HAVING clauses. Trivial table expressions simply refer to a table on disk, a so-called base table, but more complex expressions can be used to modify or combine base tables in various ways. The optional WHERE, GROUP BY, and HAVING clauses in the table expression specify a pipeline of successive transformations performed on the table derived in the FROM clause. All

NameINSERT -- create new rows in a table Synopsis [ WITH [ RECURSIVE ] with_query [, ...] ] INSERT INTO table_name [ AS alias ] [ ( column_name [, ...] ) ] { DEFAULT VALUES | VALUES ( { expression | DEFAULT } [, ...] ) [, ...] | query } [ ON CONFLICT [ conflict_target ] conflict_action ] [ RETURNING * | output_expression [ [ AS ] output_name ] [, ...] ] where conflict_target can be one of: ( { index_column_name | ( index_expression ) } [ COLLATE collation ] [ opclass ] [

Client authentication is controlled by a configuration file, which traditionally is named pg_hba.conf and is stored in the database cluster's data directory. (HBA stands for host-based authentication.) A default pg_hba.conf file is installed when the data directory is initialized by initdb. It is possible to place the authentication configuration file elsewhere, however; see the hba_file configuration parameter. The general format of the pg_hba.conf file is a set of records, one per line. Blank

The postgres_fdw module provides the foreign-data wrapper postgres_fdw, which can be used to access data stored in external PostgreSQL servers. The functionality provided by this module overlaps substantially with the functionality of the older dblink module. But postgres_fdw provides more transparent and standards-compliant syntax for accessing remote tables, and can give better performance in many cases. To prepare for remote access using postgres_fdw: Install the postgres_fdw extension usin

Namevacuumdb -- garbage-collect and analyze a PostgreSQL database Synopsis vacuumdb [connection-option...] [option...] [ --table | -t table [( column [,...] )] ] ... [dbname] vacuumdb [connection-option...] [option...] --all | -a Description vacuumdb is a utility for cleaning a PostgreSQL database. vacuumdb will also generate internal statistics used by the PostgreSQL query optimizer. vacuumdb is a wrapper around the SQL command VACUUM. There is no effective difference between vacuuming

Namepostgres -- PostgreSQL database server Synopsis postgres [option...] Description postgres is the PostgreSQL database server. In order for a client application to access a database it connects (over a network or locally) to a running postgres instance. The postgres instance then starts a separate server process to handle the connection. One postgres instance always manages the data of exactly one database cluster. A database cluster is a collection of databases that is stored at a co

NameUPDATE -- update rows of a table Synopsis [ WITH [ RECURSIVE ] with_query [, ...] ] UPDATE [ ONLY ] table_name [ * ] [ [ AS ] alias ] SET { column_name = { expression | DEFAULT } | ( column_name [, ...] ) = ( { expression | DEFAULT } [, ...] ) | ( column_name [, ...] ) = ( sub-SELECT ) } [, ...] [ FROM from_list ] [ WHERE condition | WHERE CURRENT OF cursor_name ] [ RETURNING * | output_expression [ [ AS ] output_name ] [, ...] ] Descrip

The geometric types point, box, lseg, line, path, polygon, and circle have a large set of native support functions and operators, shown in Table 9-33, Table 9-34, and Table 9-35. Caution: Note that the "same as" operator, ~=, represents the usual notion of equality for the point, box, polygon, and circle types. Some of these types also have an = operator, but = compares for equal areas only. The other scalar comparison operators (<= and so on) likewise compare areas for these types. Tabl