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PostgreSQL documentation

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<para>

The function <function>current_setting</function> yields the

current value of the setting <parameter>setting_name</parameter>,

as part of a query result. It corresponds to the

<acronym>SQL</acronym> command <command>SHOW</command>. An

example:

current value of the setting <parameter>setting_name</parameter>.

It corresponds to the <acronym>SQL</acronym> command

<command>SHOW</command>. An example:

<programlisting>

SELECT current_setting('datestyle');

<primary>pg_get_constraintdef</primary>

</indexterm>

<indexterm zone="functions-misc">

<primary>pg_get_expr</primary>

</indexterm>

<indexterm zone="functions-misc">

<primary>pg_get_userbyid</primary>

</indexterm>

<function>pg_get_constraintdef</function> respectively

reconstruct the creating command for a view, rule, index, or

constraint. (Note that this is a decompiled reconstruction, not

the verbatim text of the command.)

the original text of the command.) Most of these come in two

variants, one of which can optionally <quote>pretty-print</> the result.

The pretty-printed form is more readable but is less likely to be

interpreted the same way by future versions of <productname>PostgreSQL</>;

avoid using pretty-printed output for dump purposes.

Passing <literal>false</> for the pretty-print parameter yields the

same result as the variant that does not have the parameter at all.

<function>pg_get_expr</function> decompiles the internal form of an

individual expression, such as the default value for a column. It

may be useful when examining the contents of system catalogs.

<function>pg_get_userbyid</function>

extracts a user's name given a user ID number.

</para>

<entry><type>text</type></entry>

<entry>get <command>CREATE VIEW</> command for view (<emphasis>deprecated</emphasis>)</entry>

</row>

<row>

<entry><literal><function>pg_get_viewdef</function>(<parameter>view_name</parameter>, <parameter>pretty_bool</>)</literal></entry>

<entry><type>text</type></entry>

<entry>get <command>CREATE VIEW</> command for view (<emphasis>deprecated</emphasis>)</entry>

</row>

<row>

<entry><literal><function>pg_get_viewdef</function>(<parameter>view_oid</parameter>)</literal></entry>

<entry><type>text</type></entry>

<entry>get <command>CREATE VIEW</> command for view</entry>

</row>

<row>

<entry><literal><function>pg_get_viewdef</function>(<parameter>view_oid</parameter>, <parameter>pretty_bool</>)</literal></entry>

<entry><type>text</type></entry>

<entry>get <command>CREATE VIEW</> command for view</entry>

</row>

<row>

<entry><literal><function>pg_get_ruledef</function>(<parameter>rule_oid</parameter>)</literal></entry>

<entry><type>text</type></entry>

<entry>get <command>CREATE RULE</> command for rule</entry>

</row>

<row>

<entry><literal><function>pg_get_ruledef</function>(<parameter>rule_oid</parameter>, <parameter>pretty_bool</>)</literal></entry>

<entry><type>text</type></entry>

<entry>get <command>CREATE RULE</> command for rule</entry>

</row>

<row>

<entry><literal><function>pg_get_indexdef</function>(<parameter>index_oid</parameter>)</literal></entry>

<entry><type>text</type></entry>

<entry>get <command>CREATE INDEX</> command for index</entry>

</row>

<row>

<entry><literal><function>pg_get_indexdef</function>(<parameter>index_oid</parameter>, <parameter>column_no</>, <parameter>pretty_bool</>)</literal></entry>

<entry><type>text</type></entry>

<entry>get <command>CREATE INDEX</> command for index,

or definition of just one index column when

<parameter>column_no</> is not zero</entry>

</row>

<row>

<entry><function>pg_get_triggerdef</function>(<parameter>trigger_oid</parameter>)</entry>

<entry><type>text</type></entry>

<entry><type>text</type></entry>

<entry>get definition of a constraint</entry>

</row>

<row>

<entry><literal><function>pg_get_constraintdef</function>(<parameter>constraint_oid</parameter>, <parameter>pretty_bool</>)</literal></entry>

<entry><type>text</type></entry>

<entry>get definition of a constraint</entry>

</row>

<row>

<entry><literal><function>pg_get_expr</function>(<parameter>expr_text</parameter>, <parameter>relation_oid</>)</literal></entry>

<entry><type>text</type></entry>

<entry>decompile internal form of an expression, assuming that any Vars

in it refer to the relation indicated by the second parameter</entry>

</row>

<row>

<entry><literal><function>pg_get_expr</function>(<parameter>expr_text</parameter>, <parameter>relation_oid</>, <parameter>pretty_bool</>)</literal></entry>

<entry><type>text</type></entry>

<entry>decompile internal form of an expression, assuming that any Vars

in it refer to the relation indicated by the second parameter</entry>

</row>

<row>

<entry><literal><function>pg_get_userbyid</function>(<parameter>userid</parameter>)</literal></entry>

<entry><type>name</type></entry>