<function>sum</function>, <function>count</function>, and
<function>max</function>. Each entry in
<structname>pg_aggregate</structname> is an extension of an entry
- in <structname>pg_proc</structname>. The <structname>pg_proc</structname>
- entry carries the aggregate's name, input and output data types, and
- other information that is similar to ordinary functions.
+ in <link linkend="catalog-pg-proc"><structname>pg_proc</structname></link>.
+ The <structname>pg_proc</structname> entry carries the aggregate's name,
+ input and output data types, and other information that is similar to
+ ordinary functions.
</para>
<table>
catalog structure for performance reasons). Also,
<structfield>amoplefttype</structfield> and <structfield>amoprighttype</structfield> must match
the <structfield>oprleft</structfield> and <structfield>oprright</structfield> fields of the
- referenced <structname>pg_operator</structname> entry.
+ referenced <link linkend="catalog-pg-operator"><structname>pg_operator</structname></link> entry.
</para>
</sect1>
table columns. There will be exactly one
<structname>pg_attribute</structname> row for every column in every
table in the database. (There will also be attribute entries for
- indexes, and indeed all objects that have <structname>pg_class</structname>
+ indexes, and indeed all objects that have
+ <link linkend="catalog-pg-class"><structname>pg_class</structname></link>
entries.)
</para>
<para>
This column has a default expression or generation expression, in which
case there will be a corresponding entry in the
- <structname>pg_attrdef</structname> catalog that actually defines the
+ <link linkend="catalog-pg-attrdef"><structname>pg_attrdef</structname></link> catalog that actually defines the
expression. (Check <structfield>attgenerated</structfield> to
determine whether this is a default or a generation expression.)
</para></entry>
In a dropped column's <structname>pg_attribute</structname> entry,
<structfield>atttypid</structfield> is reset to zero, but
<structfield>attlen</structfield> and the other fields copied from
- <structname>pg_type</structname> are still valid. This arrangement is needed
+ <link linkend="catalog-pg-type"><structname>pg_type</structname></link> are still valid. This arrangement is needed
to cope with the situation where the dropped column's data type was
later dropped, and so there is no <structname>pg_type</structname> row anymore.
<structfield>attlen</structfield> and the other fields can be used
<para>
The catalog <structname>pg_class</structname> catalogs tables and most
everything else that has columns or is otherwise similar to a
- table. This includes indexes (but see also
- <structname>pg_index</structname>), sequences (but see also
- <structname>pg_sequence</structname>), views, materialized
- views, composite types, and TOAST tables; see <structfield>relkind</structfield>.
- Below, when we mean all of these
- kinds of objects we speak of <quote>relations</quote>. Not all
- columns are meaningful for all relation types.
+ table. This includes indexes (but see also <link
+ linkend="catalog-pg-index"><structname>pg_index</structname></link>),
+ sequences (but see also <link
+ linkend="catalog-pg-sequence"><structname>pg_sequence</structname></link>),
+ views, materialized views, composite types, and TOAST tables;
+ see <structfield>relkind</structfield>.
+ Below, when we mean all of these kinds of objects we speak of
+ <quote>relations</quote>. Not all columns are meaningful for all relation
+ types.
</para>
<table>
</para>
<para>
True if this table is shared across all databases in the cluster. Only
- certain system catalogs (such as <structname>pg_database</structname>)
+ certain system catalogs (such as <link linkend="catalog-pg-database"><structname>pg_database</structname></link>)
are shared.
</para></entry>
</row>
<para>
Number of user columns in the relation (system columns not
counted). There must be this many corresponding entries in
- <structname>pg_attribute</structname>. See also
- <literal>pg_attribute.attnum</literal>.
+ <link linkend="catalog-pg-attribute"><structname>pg_attribute</structname></link>. See also
+ <structname>pg_attribute</structname>.<structfield>attnum</structfield>.
</para></entry>
</row>
key, unique, foreign key, and exclusion constraints on tables.
(Column constraints are not treated specially. Every column constraint is
equivalent to some table constraint.)
- Not-null constraints are represented in the <structname>pg_attribute</structname>
+ Not-null constraints are represented in the
+ <link linkend="catalog-pg-attribute"><structname>pg_attribute</structname></link>
catalog, not here.
</para>
For other cases, a zero appears in <structfield>conkey</structfield>
and the associated index must be consulted to discover the expression
that is constrained. (<structfield>conkey</structfield> thus has the
- same contents as <structname>pg_index</structname>.<structfield>indkey</structfield> for the
+ same contents as <link linkend="catalog-pg-index"><structname>pg_index</structname></link>.<structfield>indkey</structfield> for the
index.)
</para>
track whether the database needs to be vacuumed in order to prevent
transaction ID wraparound or to allow <literal>pg_xact</literal> to be shrunk.
It is the minimum of the per-table
- <structname>pg_class</structname>.<structfield>relfrozenxid</structfield> values.
+ <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relfrozenxid</structfield> values.
</para></entry>
</row>
track whether the database needs to be vacuumed in order to prevent
multixact ID wraparound or to allow <literal>pg_multixact</literal> to be shrunk.
It is the minimum of the per-table
- <structname>pg_class</structname>.<structfield>relminmxid</structfield> values.
+ <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relminmxid</structfield> values.
</para></entry>
</row>
<para>
The default tablespace for the database.
Within this database, all tables for which
- <structname>pg_class</structname>.<structfield>reltablespace</structfield> is zero
+ <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>reltablespace</structfield> is zero
will be stored in this tablespace; in particular, all the non-shared
system catalogs will be there.
</para></entry>
(references <link linkend="catalog-pg-type"><structname>pg_type</structname></link>.<structfield>oid</structfield>)
</para>
<para>
- The OID of the <structname>pg_type</structname> entry owning this enum value
+ The OID of the <link linkend="catalog-pg-type"><structname>pg_type</structname></link> entry owning this enum value
</para></entry>
</row>
<para>
The catalog <structname>pg_foreign_table</structname> contains
auxiliary information about foreign tables. A foreign table is
- primarily represented by a <structname>pg_class</structname> entry,
- just like a regular table. Its <structname>pg_foreign_table</structname>
+ primarily represented by a
+ <link linkend="catalog-pg-class"><structname>pg_class</structname></link>
+ entry, just like a regular table. Its <structname>pg_foreign_table</structname>
entry contains the information that is pertinent only to foreign tables
and not any other kind of relation.
</para>
(references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>oid</structfield>)
</para>
<para>
- OID of the <structname>pg_class</structname> entry for this foreign table
+ The OID of the <link linkend="catalog-pg-class"><structname>pg_class</structname></link> entry for this foreign table
</para></entry>
</row>
<para>
The catalog <structname>pg_index</structname> contains part of the information
about indexes. The rest is mostly in
- <structname>pg_class</structname>.
+ <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.
</para>
<table>
(references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>oid</structfield>)
</para>
<para>
- The OID of the <structname>pg_class</structname> entry for this index
+ The OID of the <link linkend="catalog-pg-class"><structname>pg_class</structname></link> entry for this index
</para></entry>
</row>
(references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>oid</structfield>)
</para>
<para>
- The OID of the <structname>pg_class</structname> entry for the table this index is for
+ The OID of the <link linkend="catalog-pg-class"><structname>pg_class</structname></link> entry for the table this index is for
</para></entry>
</row>
(references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>oid</structfield>)
</para>
<para>
- The OID of the <structname>pg_class</structname> entry for this partitioned table
+ The OID of the <link linkend="catalog-pg-class"><structname>pg_class</structname></link> entry for this partitioned table
</para></entry>
</row>
(references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>oid</structfield>)
</para>
<para>
- The OID of the <structname>pg_class</structname> entry for the default partition
+ The OID of the <link linkend="catalog-pg-class"><structname>pg_class</structname></link> entry for the default partition
of this partitioned table, or zero if this partitioned table does not
have a default partition.
</para></entry>
<note>
<para>
Policies stored in <structname>pg_policy</structname> are applied only when
- <structname>pg_class</structname>.<structfield>relrowsecurity</structfield> is set for
+ <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relrowsecurity</structfield> is set for
their table.
</para>
</note>
<para>
If <structfield>prokind</structfield> indicates that the entry is for an
aggregate function, there should be a matching row in
- <structfield>pg_aggregate</structfield>.
+ <link linkend="catalog-pg-aggregate"><structfield>pg_aggregate</structfield></link>.
</para>
<table>
<para>
The catalog <structname>pg_sequence</structname> contains information about
sequences. Some of the information about sequences, such as the name and
- the schema, is in <structname>pg_class</structname>.
+ the schema, is in
+ <link linkend="catalog-pg-class"><structname>pg_class</structname></link>
</para>
<table>
(references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>oid</structfield>)
</para>
<para>
- The OID of the <structname>pg_class</structname> entry for this sequence
+ The OID of the <link linkend="catalog-pg-class"><structname>pg_class</structname></link> entry for this sequence
</para></entry>
</row>
<para>
The catalog <structname>pg_statistic_ext_data</structname>
- holds data for extended planner statistics defined in <structname>pg_statistic_ext</structname>.
+ holds data for extended planner statistics defined in
+ <link linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link>.
Each row in this catalog corresponds to a <firstterm>statistics object</firstterm>
created with <xref linkend="sql-createstatistics"/>.
</para>
<para>
- Like <structname>pg_statistic</structname>,
+ Like <link linkend="catalog-pg-statistic"><structname>pg_statistic</structname></link>,
<structname>pg_statistic_ext_data</structname> should not be
readable by the public, since the contents might be considered sensitive.
(Example: most common combinations of values in columns might be quite
<link linkend="view-pg-stats-ext"><structname>pg_stats_ext</structname></link>
is a publicly readable view
on <structname>pg_statistic_ext_data</structname> (after joining
- with <structname>pg_statistic_ext</structname>) that only exposes
+ with <link linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link>) that only exposes
information about those tables and columns that are readable by the
current user.
</para>
(references <link linkend="catalog-pg-constraint"><structname>pg_constraint</structname></link>.<structfield>oid</structfield>)
</para>
<para>
- The <structname>pg_constraint</structname> entry associated with the trigger, if any
+ The <link linkend="catalog-pg-constraint"><structname>pg_constraint</structname></link> entry associated with the trigger, if any
</para></entry>
</row>
When <structfield>tgconstraint</structfield> is nonzero,
<structfield>tgconstrrelid</structfield>, <structfield>tgconstrindid</structfield>,
<structfield>tgdeferrable</structfield>, and <structfield>tginitdeferred</structfield> are
- largely redundant with the referenced <structname>pg_constraint</structname> entry.
+ largely redundant with the referenced <link linkend="catalog-pg-constraint"><structname>pg_constraint</structname></link> entry.
However, it is possible for a non-deferrable trigger to be associated
with a deferrable constraint: foreign key constraints can have some
deferrable and some non-deferrable triggers.
(references <link linkend="catalog-pg-ts-config"><structname>pg_ts_config</structname></link>.<structfield>oid</structfield>)
</para>
<para>
- The OID of the <structname>pg_ts_config</structname> entry owning this map entry
+ The OID of the <link linkend="catalog-pg-ts-config"><structname>pg_ts_config</structname></link> entry owning this map entry
</para></entry>
</row>
<para>
If this is a composite type (see
<structfield>typtype</structfield>), then this column points to
- the <structname>pg_class</structname> entry that defines the
+ the <link linkend="catalog-pg-class"><structname>pg_class</structname></link> entry that defines the
corresponding table. (For a free-standing composite type, the
- <structname>pg_class</structname> entry doesn't really represent
+ <link linkend="catalog-pg-class"><structname>pg_class</structname></link> entry doesn't really represent
a table, but it is needed anyway for the type's
- <structname>pg_attribute</structname> entries to link to.)
+ <link linkend="catalog-pg-attribute"><structname>pg_attribute</structname></link> entries to link to.)
Zero for non-composite types.
</para></entry>
</row>
<para>
The view <structname>pg_hba_file_rules</structname> provides a summary of
- the contents of the client authentication configuration
- file, <filename>pg_hba.conf</filename>. A row appears in this view for each
+ the contents of the client authentication configuration file,
+ <link linkend="auth-pg-hba-conf"><filename>pg_hba.conf</filename></link>.
+ A row appears in this view for each
non-empty, non-comment line in the file, with annotations indicating
whether the rule could be applied successfully.
</para>
individual tuples of relations,
transaction IDs (both virtual and permanent IDs),
and general database objects (identified by class OID and object OID,
- in the same way as in <structname>pg_description</structname> or
- <structname>pg_depend</structname>). Also, the right to extend a
+ in the same way as in <link linkend="catalog-pg-description"><structname>pg_description</structname></link> or
+ <link linkend="catalog-pg-depend"><structname>pg_depend</structname></link>). Also, the right to extend a
relation is represented as a separate lockable object, as is the right to
update <structname>pg_database</structname>.<structfield>datfrozenxid</structfield>.
Also, <quote>advisory</quote> locks can be taken on numbers that have
<structname>pg_locks</structname> provides a global view of all locks
in the database cluster, not only those relevant to the current database.
Although its <structfield>relation</structfield> column can be joined
- against <structname>pg_class</structname>.<structfield>oid</structfield> to identify locked
+ against <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>oid</structfield> to identify locked
relations, this will only work correctly for relations in the current
database (those for which the <structfield>database</structfield> column
is either the current database's OID or zero).
<para>
The view <structname>pg_publication_tables</structname> provides
information about the mapping between publications and the tables they
- contain. Unlike the underlying
- catalog <structname>pg_publication_rel</structname>, this view expands
+ contain. Unlike the underlying catalog
+ <link linkend="catalog-pg-publication-rel"><structname>pg_publication_rel</structname></link>,
+ this view expands
publications defined as <literal>FOR ALL TABLES</literal>, so for such
publications there will be a row for each eligible table.
</para>
<para>
The <structname>pg_rules</structname> view excludes the <literal>ON SELECT</literal> rules
of views and materialized views; those can be seen in
- <structname>pg_views</structname> and <structname>pg_matviews</structname>.
+ <link linkend="view-pg-views"><structname>pg_views</structname></link> and <link linkend="view-pg-matviews"><structname>pg_matviews</structname></link>.
</para>
</sect1>
the information stored in the <link
linkend="catalog-pg-statistic"><structname>pg_statistic</structname></link>
catalog. This view allows access only to rows of
- <structname>pg_statistic</structname> that correspond to tables the
+ <link linkend="catalog-pg-statistic"><structname>pg_statistic</structname></link> that correspond to tables the
user has permission to read, and therefore it is safe to allow public
read access to this view.
</para>
<structname>pg_stats</structname> is also designed to present the
information in a more readable format than the underlying catalog
— at the cost that its schema must be extended whenever new slot types
- are defined for <structname>pg_statistic</structname>.
+ are defined for <link linkend="catalog-pg-statistic"><structname>pg_statistic</structname></link>.
</para>
<table>
linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link>
and <link linkend="catalog-pg-statistic-ext-data"><structname>pg_statistic_ext_data</structname></link>
catalogs. This view allows access only to rows of
- <structname>pg_statistic_ext</structname> and <structname>pg_statistic_ext_data</structname>
+ <link linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link> and <link linkend="catalog-pg-statistic-ext-data"><structname>pg_statistic_ext_data</structname></link>
that correspond to tables the user has permission to read, and therefore
it is safe to allow public read access to this view.
</para>
<structname>pg_stats_ext</structname> is also designed to present the
information in a more readable format than the underlying catalogs
— at the cost that its schema must be extended whenever new types
- of extended statistics are added to <structname>pg_statistic_ext</structname>.
+ of extended statistics are added to <link linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link>.
</para>
<table>
projects / postgresql.git / commitdiff