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diff --git a/doc/src/sgml/html/catalog-pg-depend.html b/doc/src/sgml/html/catalog-pg-depend.html new file mode 100644 index 0000000..adf6a59 --- /dev/null +++ b/doc/src/sgml/html/catalog-pg-depend.html @@ -0,0 +1,175 @@ +<?xml version="1.0" encoding="UTF-8" standalone="no"?> +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>53.18. pg_depend</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="catalog-pg-default-acl.html" title="53.17. pg_default_acl" /><link rel="next" href="catalog-pg-description.html" title="53.19. pg_description" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">53.18. <code class="structname">pg_depend</code></th></tr><tr><td width="10%" align="left"><a accesskey="p" href="catalog-pg-default-acl.html" title="53.17. pg_default_acl">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="catalogs.html" title="Chapter 53. System Catalogs">Up</a></td><th width="60%" align="center">Chapter 53. System Catalogs</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 15.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="catalog-pg-description.html" title="53.19. pg_description">Next</a></td></tr></table><hr /></div><div class="sect1" id="CATALOG-PG-DEPEND"><div class="titlepage"><div><div><h2 class="title" style="clear: both">53.18. <code class="structname">pg_depend</code></h2></div></div></div><a id="id-1.10.4.20.2" class="indexterm"></a><p> + The catalog <code class="structname">pg_depend</code> records the dependency + relationships between database objects. This information allows + <code class="command">DROP</code> commands to find which other objects must be dropped + by <code class="command">DROP CASCADE</code> or prevent dropping in the <code class="command">DROP + RESTRICT</code> case. + </p><p> + See also <a class="link" href="catalog-pg-shdepend.html" title="53.48. pg_shdepend"><code class="structname">pg_shdepend</code></a>, + which performs a similar function for dependencies involving objects + that are shared across a database cluster. + </p><div class="table" id="id-1.10.4.20.5"><p class="title"><strong>Table 53.18. <code class="structname">pg_depend</code> Columns</strong></p><div class="table-contents"><table class="table" summary="pg_depend Columns" border="1"><colgroup><col /></colgroup><thead><tr><th class="catalog_table_entry"><p class="column_definition"> + Column Type + </p> + <p> + Description + </p></th></tr></thead><tbody><tr><td class="catalog_table_entry"><p class="column_definition"> + <code class="structfield">classid</code> <code class="type">oid</code> + (references <a class="link" href="catalog-pg-class.html" title="53.11. pg_class"><code class="structname">pg_class</code></a>.<code class="structfield">oid</code>) + </p> + <p> + The OID of the system catalog the dependent object is in + </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition"> + <code class="structfield">objid</code> <code class="type">oid</code> + (references any OID column) + </p> + <p> + The OID of the specific dependent object + </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition"> + <code class="structfield">objsubid</code> <code class="type">int4</code> + </p> + <p> + For a table column, this is the column number (the + <code class="structfield">objid</code> and <code class="structfield">classid</code> refer to the + table itself). For all other object types, this column is + zero. + </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition"> + <code class="structfield">refclassid</code> <code class="type">oid</code> + (references <a class="link" href="catalog-pg-class.html" title="53.11. pg_class"><code class="structname">pg_class</code></a>.<code class="structfield">oid</code>) + </p> + <p> + The OID of the system catalog the referenced object is in + </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition"> + <code class="structfield">refobjid</code> <code class="type">oid</code> + (references any OID column) + </p> + <p> + The OID of the specific referenced object + </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition"> + <code class="structfield">refobjsubid</code> <code class="type">int4</code> + </p> + <p> + For a table column, this is the column number (the + <code class="structfield">refobjid</code> and <code class="structfield">refclassid</code> refer + to the table itself). For all other object types, this column + is zero. + </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition"> + <code class="structfield">deptype</code> <code class="type">char</code> + </p> + <p> + A code defining the specific semantics of this dependency relationship; see text + </p></td></tr></tbody></table></div></div><br class="table-break" /><p> + In all cases, a <code class="structname">pg_depend</code> entry indicates that the + referenced object cannot be dropped without also dropping the dependent + object. However, there are several subflavors identified by + <code class="structfield">deptype</code>: + + </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="symbol">DEPENDENCY_NORMAL</code> (<code class="literal">n</code>)</span></dt><dd><p> + A normal relationship between separately-created objects. The + dependent object can be dropped without affecting the + referenced object. The referenced object can only be dropped + by specifying <code class="literal">CASCADE</code>, in which case the dependent + object is dropped, too. Example: a table column has a normal + dependency on its data type. + </p></dd><dt><span class="term"><code class="symbol">DEPENDENCY_AUTO</code> (<code class="literal">a</code>)</span></dt><dd><p> + The dependent object can be dropped separately from the + referenced object, and should be automatically dropped + (regardless of <code class="literal">RESTRICT</code> or <code class="literal">CASCADE</code> + mode) if the referenced object is dropped. Example: a named + constraint on a table is made auto-dependent on the table, so + that it will go away if the table is dropped. + </p></dd><dt><span class="term"><code class="symbol">DEPENDENCY_INTERNAL</code> (<code class="literal">i</code>)</span></dt><dd><p> + The dependent object was created as part of creation of the + referenced object, and is really just a part of its internal + implementation. A direct <code class="command">DROP</code> of the dependent + object will be disallowed outright (we'll tell the user to issue + a <code class="command">DROP</code> against the referenced object, instead). + A <code class="command">DROP</code> of the referenced object will result in + automatically dropping the dependent object + whether <code class="literal">CASCADE</code> is specified or not. If the + dependent object has to be dropped due to a dependency on some other + object being removed, its drop is converted to a drop of the referenced + object, so that <code class="literal">NORMAL</code> and <code class="literal">AUTO</code> + dependencies of the dependent object behave much like they were + dependencies of the referenced object. + Example: a view's <code class="literal">ON SELECT</code> rule is made + internally dependent on the view, preventing it from being dropped + while the view remains. Dependencies of the rule (such as tables it + refers to) act as if they were dependencies of the view. + </p></dd><dt><span class="term"><code class="symbol">DEPENDENCY_PARTITION_PRI</code> (<code class="literal">P</code>)<br /></span><span class="term"><code class="symbol">DEPENDENCY_PARTITION_SEC</code> (<code class="literal">S</code>)</span></dt><dd><p> + The dependent object was created as part of creation of the + referenced object, and is really just a part of its internal + implementation; however, unlike <code class="literal">INTERNAL</code>, + there is more than one such referenced object. The dependent object + must not be dropped unless at least one of these referenced objects + is dropped; if any one is, the dependent object should be dropped + whether or not <code class="literal">CASCADE</code> is specified. Also + unlike <code class="literal">INTERNAL</code>, a drop of some other object + that the dependent object depends on does not result in automatic + deletion of any partition-referenced object. Hence, if the drop + does not cascade to at least one of these objects via some other + path, it will be refused. (In most cases, the dependent object + shares all its non-partition dependencies with at least one + partition-referenced object, so that this restriction does not + result in blocking any cascaded delete.) + Primary and secondary partition dependencies behave identically + except that the primary dependency is preferred for use in error + messages; hence, a partition-dependent object should have one + primary partition dependency and one or more secondary partition + dependencies. + Note that partition dependencies are made in addition to, not + instead of, any dependencies the object would normally have. This + simplifies <code class="command">ATTACH/DETACH PARTITION</code> operations: + the partition dependencies need only be added or removed. + Example: a child partitioned index is made partition-dependent + on both the partition table it is on and the parent partitioned + index, so that it goes away if either of those is dropped, but + not otherwise. The dependency on the parent index is primary, + so that if the user tries to drop the child partitioned index, + the error message will suggest dropping the parent index instead + (not the table). + </p></dd><dt><span class="term"><code class="symbol">DEPENDENCY_EXTENSION</code> (<code class="literal">e</code>)</span></dt><dd><p> + The dependent object is a member of the <em class="firstterm">extension</em> that is + the referenced object (see + <a class="link" href="catalog-pg-extension.html" title="53.22. pg_extension"><code class="structname">pg_extension</code></a>). + The dependent object can be dropped only via + <a class="link" href="sql-dropextension.html" title="DROP EXTENSION"><code class="command">DROP EXTENSION</code></a> on the referenced object. + Functionally this dependency type acts the same as + an <code class="literal">INTERNAL</code> dependency, but it's kept separate for + clarity and to simplify <span class="application">pg_dump</span>. + </p></dd><dt><span class="term"><code class="symbol">DEPENDENCY_AUTO_EXTENSION</code> (<code class="literal">x</code>)</span></dt><dd><p> + The dependent object is not a member of the extension that is the + referenced object (and so it should not be ignored + by <span class="application">pg_dump</span>), but it cannot function + without the extension and should be auto-dropped if the extension is. + The dependent object may be dropped on its own as well. + Functionally this dependency type acts the same as + an <code class="literal">AUTO</code> dependency, but it's kept separate for + clarity and to simplify <span class="application">pg_dump</span>. + </p></dd></dl></div><p> + + Other dependency flavors might be needed in future. + </p><p> + Note that it's quite possible for two objects to be linked by more than + one <code class="structname">pg_depend</code> entry. For example, a child + partitioned index would have both a partition-type dependency on its + associated partition table, and an auto dependency on each column of + that table that it indexes. This sort of situation expresses the union + of multiple dependency semantics. A dependent object can be dropped + without <code class="literal">CASCADE</code> if any of its dependencies satisfies + its condition for automatic dropping. Conversely, all the + dependencies' restrictions about which objects must be dropped together + must be satisfied. + </p><p> + Most objects created during <span class="application">initdb</span> are + considered <span class="quote">“<span class="quote">pinned</span>”</span>, which means that the system itself + depends on them. Therefore, they are never allowed to be dropped. + Also, knowing that pinned objects will not be dropped, the dependency + mechanism doesn't bother to make <code class="structname">pg_depend</code> + entries showing dependencies on them. Thus, for example, a table + column of type <code class="type">numeric</code> notionally has + a <code class="literal">NORMAL</code> dependency on the <code class="type">numeric</code> + data type, but no such entry actually appears + in <code class="structname">pg_depend</code>. + </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="catalog-pg-default-acl.html" title="53.17. pg_default_acl">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="catalogs.html" title="Chapter 53. 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