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   2 <!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>52.48. pg_shdepend</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-sequence.html" title="52.47. pg_sequence" /><link rel="next" href="catalog-pg-shdescription.html" title="52.49. pg_shdescription" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">52.48. <code class="structname">pg_shdepend</code></th></tr><tr><td width="10%" align="left"><a accesskey="p" href="catalog-pg-sequence.html" title="52.47. pg_sequence">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="catalogs.html" title="Chapter 52. System Catalogs">Up</a></td><th width="60%" align="center">Chapter 52. System Catalogs</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 18.0 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="catalog-pg-shdescription.html" title="52.49. pg_shdescription">Next</a></td></tr></table><hr /></div><div class="sect1" id="CATALOG-PG-SHDEPEND"><div class="titlepage"><div><div><h2 class="title" style="clear: both">52.48. <code class="structname">pg_shdepend</code> <a href="#CATALOG-PG-SHDEPEND" class="id_link">#</a></h2></div></div></div><a id="id-1.10.4.50.2" class="indexterm"></a><p>
   3    The catalog <code class="structname">pg_shdepend</code> records the
   4    dependency relationships between database objects and shared objects,
   5    such as roles.  This information allows
   6    <span class="productname">PostgreSQL</span> to ensure that those objects are
   7    unreferenced before attempting to delete them.
   8   </p><p>
   9    See also <a class="link" href="catalog-pg-depend.html" title="52.18. pg_depend"><code class="structname">pg_depend</code></a>,
  10    which performs a similar function for dependencies involving objects
  11    within a single database.
  12   </p><p>
  13    Unlike most system catalogs, <code class="structname">pg_shdepend</code>
  14    is shared across all databases of a cluster: there is only one
  15    copy of <code class="structname">pg_shdepend</code> per cluster, not
  16    one per database.
  17   </p><div class="table" id="id-1.10.4.50.6"><p class="title"><strong>Table 52.48. <code class="structname">pg_shdepend</code> Columns</strong></p><div class="table-contents"><table class="table" summary="pg_shdepend Columns" border="1"><colgroup><col /></colgroup><thead><tr><th class="catalog_table_entry"><p class="column_definition">
  18        Column Type
  19       </p>
  20       <p>
  21        Description
  22       </p></th></tr></thead><tbody><tr><td class="catalog_table_entry"><p class="column_definition">
  23        <code class="structfield">dbid</code> <code class="type">oid</code>
  24        (references <a class="link" href="catalog-pg-database.html" title="52.15. pg_database"><code class="structname">pg_database</code></a>.<code class="structfield">oid</code>)
  25       </p>
  26       <p>
  27        The OID of the database the dependent object is in,
  28        or zero for a shared object
  29       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
  30        <code class="structfield">classid</code> <code class="type">oid</code>
  31        (references <a class="link" href="catalog-pg-class.html" title="52.11. pg_class"><code class="structname">pg_class</code></a>.<code class="structfield">oid</code>)
  32       </p>
  33       <p>
  34        The OID of the system catalog the dependent object is in
  35       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
  36        <code class="structfield">objid</code> <code class="type">oid</code>
  37        (references any OID column)
  38       </p>
  39       <p>
  40        The OID of the specific dependent object
  41       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
  42        <code class="structfield">objsubid</code> <code class="type">int4</code>
  43       </p>
  44       <p>
  45        For a table column, this is the column number (the
  46        <code class="structfield">objid</code> and <code class="structfield">classid</code> refer to the
  47        table itself).  For all other object types, this column is zero.
  48       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
  49        <code class="structfield">refclassid</code> <code class="type">oid</code>
  50        (references <a class="link" href="catalog-pg-class.html" title="52.11. pg_class"><code class="structname">pg_class</code></a>.<code class="structfield">oid</code>)
  51       </p>
  52       <p>
  53        The OID of the system catalog the referenced object is in
  54        (must be a shared catalog)
  55       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
  56        <code class="structfield">refobjid</code> <code class="type">oid</code>
  57        (references any OID column)
  58       </p>
  59       <p>
  60        The OID of the specific referenced object
  61       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
  62        <code class="structfield">deptype</code> <code class="type">char</code>
  63       </p>
  64       <p>
  65        A code defining the specific semantics of this dependency relationship; see text
  66       </p></td></tr></tbody></table></div></div><br class="table-break" /><p>
  67    In all cases, a <code class="structname">pg_shdepend</code> entry indicates that
  68    the referenced object cannot be dropped without also dropping the dependent
  69    object.  However, there are several subflavors identified by
  70    <code class="structfield">deptype</code>:
  71
  72    </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="symbol">SHARED_DEPENDENCY_OWNER</code> (<code class="literal">o</code>)</span></dt><dd><p>
  73        The referenced object (which must be a role) is the owner of the
  74        dependent object.
  75       </p></dd><dt><span class="term"><code class="symbol">SHARED_DEPENDENCY_ACL</code> (<code class="literal">a</code>)</span></dt><dd><p>
  76        The referenced object (which must be a role) is mentioned in the
  77        <acronym class="acronym">ACL</acronym> of the
  78        dependent object.  (A <code class="symbol">SHARED_DEPENDENCY_ACL</code> entry is
  79        not made for the owner of the object, since the owner will have
  80        a <code class="symbol">SHARED_DEPENDENCY_OWNER</code> entry anyway.)
  81       </p></dd><dt><span class="term"><code class="symbol">SHARED_DEPENDENCY_INITACL</code> (<code class="literal">i</code>)</span></dt><dd><p>
  82        The referenced object (which must be a role) is mentioned in a
  83        <a class="link" href="catalog-pg-init-privs.html" title="52.28. pg_init_privs"><code class="structname">pg_init_privs</code></a>
  84        entry for the dependent object.
  85       </p></dd><dt><span class="term"><code class="symbol">SHARED_DEPENDENCY_POLICY</code> (<code class="literal">r</code>)</span></dt><dd><p>
  86        The referenced object (which must be a role) is mentioned as the
  87        target of a dependent policy object.
  88       </p></dd><dt><span class="term"><code class="symbol">SHARED_DEPENDENCY_TABLESPACE</code> (<code class="literal">t</code>)</span></dt><dd><p>
  89        The referenced object (which must be a tablespace) is mentioned as
  90        the tablespace for a relation that doesn't have storage.
  91       </p></dd></dl></div><p>
  92
  93    Other dependency flavors might be needed in future.  Note in particular
  94    that the current definition only supports roles and tablespaces as referenced
  95    objects.
  96   </p><p>
  97    As in the <code class="structname">pg_depend</code> catalog, most objects
  98    created during <span class="application">initdb</span> are
  99    considered <span class="quote">“<span class="quote">pinned</span>”</span>.  No entries are made
 100    in <code class="structname">pg_shdepend</code> that would have a pinned
 101    object as either referenced or dependent object.
 102   </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="catalog-pg-sequence.html" title="52.47. pg_sequence">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="catalogs.html" title="Chapter 52. System Catalogs">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="catalog-pg-shdescription.html" title="52.49. pg_shdescription">Next</a></td></tr><tr><td width="40%" align="left" valign="top">52.47. <code class="structname">pg_sequence</code> </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 18.0 Documentation">Home</a></td><td width="40%" align="right" valign="top"> 52.49. <code class="structname">pg_shdescription</code></td></tr></table></div></body></html>