This section describes functions for operating on sequence objects, also called sequence generators or just sequences. Sequence objects are special single-row tables created with CREATE SEQUENCE. Sequence objects are commonly used to generate unique identifiers for rows of a table. The sequence functions, listed in Table 9-46, provide simple, multiuser-safe methods for obtaining successive sequence values from sequence objects. Table 9-46. Sequence Functions Function Return Type Description c

sepgsql is a loadable module that supports label-based mandatory access control (MAC) based on SELinux security policy. Warning The current implementation has significant limitations, and does not enforce mandatory access control for all actions. See Section F.35.7. F.35.1. Overview This module integrates with SELinux to provide an additional layer of security checking above and beyond what is normally provided by PostgreSQL. From the perspective of SELinux, this module allows PostgreSQL t

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

NameSELECT INTO -- define a new table from the results of a query Synopsis [ WITH [ RECURSIVE ] with_query [, ...] ] SELECT [ ALL | DISTINCT [ ON ( expression [, ...] ) ] ] * | expression [ [ AS ] output_name ] [, ...] INTO [ TEMPORARY | TEMP | UNLOGGED ] [ TABLE ] new_table [ FROM from_item [, ...] ] [ WHERE condition ] [ GROUP BY expression [, ...] ] [ HAVING condition [, ...] ] [ WINDOW window_name AS ( window_definition ) [, ...] ] [ { UNION | INTERSECT

NameSELECT, TABLE, WITH -- retrieve rows from a table or view Synopsis [ WITH [ RECURSIVE ] with_query [, ...] ] SELECT [ ALL | DISTINCT [ ON ( expression [, ...] ) ] ] [ * | expression [ [ AS ] output_name ] [, ...] ] [ FROM from_item [, ...] ] [ WHERE condition ] [ GROUP BY grouping_element [, ...] ] [ HAVING condition [, ...] ] [ WINDOW window_name AS ( window_definition ) [, ...] ] [ { UNION | INTERSECT | EXCEPT } [ ALL | DISTINCT ] select ] [ ORDER BY

This module implements a data type seg for representing line segments, or floating point intervals. seg can represent uncertainty in the interval endpoints, making it especially useful for representing laboratory measurements. F.34.1. Rationale The geometry of measurements is usually more complex than that of a point in a numeric continuum. A measurement is usually a segment of that continuum with somewhat fuzzy limits. The measurements come out as intervals because of uncertainty and randomne

NameSECURITY LABEL -- define or change a security label applied to an object Synopsis SECURITY LABEL [ FOR provider ] ON { TABLE object_name | COLUMN table_name.column_name | AGGREGATE aggregate_name ( aggregate_signature ) | DATABASE object_name | DOMAIN object_name | EVENT TRIGGER object_name | FOREIGN TABLE object_name FUNCTION function_name ( [ [ argmode ] [ argname ] argtype [, ...] ] ) | LARGE OBJECT large_object_oid | MATERIALIZED VIEW object_name | [ PROCEDUR

PostgreSQL has native support for using SSL connections to encrypt client/server communications for increased security. This requires that OpenSSL is installed on both client and server systems and that support in PostgreSQL is enabled at build time (see Chapter 16). With SSL support compiled in, the PostgreSQL server can be started with SSL enabled by setting the parameter ssl to on in postgresql.conf. The server will listen for both normal and SSL connections on the same TCP port, and will ne

It is possible to use SSH to encrypt the network connection between clients and a PostgreSQL server. Done properly, this provides an adequately secure network connection, even for non-SSL-capable clients. First make sure that an SSH server is running properly on the same machine as the PostgreSQL server and that you can log in using ssh as some user. Then you can establish a secure tunnel with a command like this from the client machine: ssh -L 63333:localhost:5432 joe@foo.com The first numbe

A PostgreSQL database cluster contains one or more named databases. Users and groups of users are shared across the entire cluster, but no other data is shared across databases. Any given client connection to the server can access only the data in a single database, the one specified in the connection request. Note: Users of a cluster do not necessarily have the privilege to access every database in the cluster. Sharing of user names means that there cannot be different users named, say, joe i