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doc-exports/docs/dws/dev/dws_04_0585.html
luhuayi 177cd61a57 DWS DEVG 910.211 version 
Reviewed-by: Pruthi, Vineet <vineet.pruthi@t-systems.com>
Co-authored-by: luhuayi <luhuayi@huawei.com>
Co-committed-by: luhuayi <luhuayi@huawei.com>
2025-05-05 07:44:03 +00:00

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<a name="EN-US_TOPIC_0000001811610313"></a><a name="EN-US_TOPIC_0000001811610313"></a>
<h1 class="topictitle1">PG_DEPEND</h1>
<div id="body8662426"><p id="EN-US_TOPIC_0000001811610313__a9096a4d734f74701b2a2fae05fc6ee9f"><strong id="EN-US_TOPIC_0000001811610313__b93171884518">PG_DEPEND</strong> records the dependency relationships between database objects. This information allows <strong id="EN-US_TOPIC_0000001811610313__en-us_topic_0058966075_b842352706162628">DROP</strong> commands to find which other objects must be dropped by <strong id="EN-US_TOPIC_0000001811610313__en-us_topic_0058966075_b842352706162637">DROP CASCADE</strong> or prevent dropping in the <strong id="EN-US_TOPIC_0000001811610313__en-us_topic_0058966075_b842352706162642">DROP RESTRICT</strong> case.</p>
<p id="EN-US_TOPIC_0000001811610313__a5567f0ffacd54fb5b06105cc61012849">See also <a href="dws_04_0616.html">PG_SHDEPEND</a>, which provides similar functionality for recording dependencies between objects that are shared between database clusters.</p>
<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" id="EN-US_TOPIC_0000001811610313__te5ced7e313ab4a77a4e7f9a0f47ff490" frame="border" border="1" rules="all"><caption><b>Table 1 </b>PG_DEPEND columns</caption><thead align="left"><tr id="EN-US_TOPIC_0000001811610313__r78c30127a1754713bcb73ccb89a06821"><th align="left" class="cellrowborder" valign="top" width="16.16%" id="mcps1.3.3.2.5.1.1"><p id="EN-US_TOPIC_0000001811610313__acb3c0bbf9dd841c18004a855fa9ef513"><strong id="EN-US_TOPIC_0000001811610313__b163981315843424">Column</strong></p>
</th>
<th align="left" class="cellrowborder" valign="top" width="11.28%" id="mcps1.3.3.2.5.1.2"><p id="EN-US_TOPIC_0000001811610313__abcf721b7e1594bd9a5906d71a37482df">Type</p>
</th>
<th align="left" class="cellrowborder" valign="top" width="21.62%" id="mcps1.3.3.2.5.1.3"><p id="EN-US_TOPIC_0000001811610313__ac101e767b72946e68a0c78ef4cf9b387">Reference</p>
</th>
<th align="left" class="cellrowborder" valign="top" width="50.94%" id="mcps1.3.3.2.5.1.4"><p id="EN-US_TOPIC_0000001811610313__af624f369916b4bafacdbf97f0a0a8374">Description</p>
</th>
</tr>
</thead>
<tbody><tr id="EN-US_TOPIC_0000001811610313__r9f5ed3d2488b4148b1c2afc271f4f185"><td class="cellrowborder" valign="top" width="16.16%" headers="mcps1.3.3.2.5.1.1 "><p id="EN-US_TOPIC_0000001811610313__a32464c32a8a7467398a053618dafa2e3">classid</p>
</td>
<td class="cellrowborder" valign="top" width="11.28%" headers="mcps1.3.3.2.5.1.2 "><p id="EN-US_TOPIC_0000001811610313__a6e7f6d825d9e42d7b901386980782602">OID</p>
</td>
<td class="cellrowborder" valign="top" width="21.62%" headers="mcps1.3.3.2.5.1.3 "><p id="EN-US_TOPIC_0000001811610313__a5646afc584cb4300bb0da9ad4ff65b32"><a href="dws_04_0578.html">PG_CLASS</a>.oid</p>
</td>
<td class="cellrowborder" valign="top" width="50.94%" headers="mcps1.3.3.2.5.1.4 "><p id="EN-US_TOPIC_0000001811610313__a27460e684c5341a09674c91f344f46c4">OID of the system catalog the dependent object is in</p>
</td>
</tr>
<tr id="EN-US_TOPIC_0000001811610313__ra399abbdfeed48a5b0472d4d2620dc77"><td class="cellrowborder" valign="top" width="16.16%" headers="mcps1.3.3.2.5.1.1 "><p id="EN-US_TOPIC_0000001811610313__a03a4afb04d4a432382fb9b8a7257e600">objid</p>
</td>
<td class="cellrowborder" valign="top" width="11.28%" headers="mcps1.3.3.2.5.1.2 "><p id="EN-US_TOPIC_0000001811610313__a1be7e2313253417292c6a9706bde2fcb">OID</p>
</td>
<td class="cellrowborder" valign="top" width="21.62%" headers="mcps1.3.3.2.5.1.3 "><p id="EN-US_TOPIC_0000001811610313__a0d0e371a90354980b5e9db5fa33809f8">Any OID column</p>
</td>
<td class="cellrowborder" valign="top" width="50.94%" headers="mcps1.3.3.2.5.1.4 "><p id="EN-US_TOPIC_0000001811610313__a7ef522037b2a4482b57ff4c371eb1222">OID of the specific dependent object</p>
</td>
</tr>
<tr id="EN-US_TOPIC_0000001811610313__rc3db053efba742d99b48a83a61967840"><td class="cellrowborder" valign="top" width="16.16%" headers="mcps1.3.3.2.5.1.1 "><p id="EN-US_TOPIC_0000001811610313__aca065edf328e4f2688cef6435ed8cdd0">objsubid</p>
</td>
<td class="cellrowborder" valign="top" width="11.28%" headers="mcps1.3.3.2.5.1.2 "><p id="EN-US_TOPIC_0000001811610313__aeadfac22f75d45f3b11ea2cc275100bf">Integer</p>
</td>
<td class="cellrowborder" valign="top" width="21.62%" headers="mcps1.3.3.2.5.1.3 "><p id="EN-US_TOPIC_0000001811610313__ae893f3ae1ea54912ae4b03f18316908a">N/A</p>
</td>
<td class="cellrowborder" valign="top" width="50.94%" headers="mcps1.3.3.2.5.1.4 "><p id="EN-US_TOPIC_0000001811610313__ad528309295694cdab6b9c7b6c5db056b">For a table column, this is the column number (the objid and classid refer to the table itself). For all other object types, this column is <strong id="EN-US_TOPIC_0000001811610313__b314412311120">0</strong>.</p>
</td>
</tr>
<tr id="EN-US_TOPIC_0000001811610313__r28bcc14297a246c187d13c2baba746c5"><td class="cellrowborder" valign="top" width="16.16%" headers="mcps1.3.3.2.5.1.1 "><p id="EN-US_TOPIC_0000001811610313__a63729c2524d841acaf36af395e928905">refclassid</p>
</td>
<td class="cellrowborder" valign="top" width="11.28%" headers="mcps1.3.3.2.5.1.2 "><p id="EN-US_TOPIC_0000001811610313__a5e855f1b6eb34ea2b8fce84dfb73e8d6">OID</p>
</td>
<td class="cellrowborder" valign="top" width="21.62%" headers="mcps1.3.3.2.5.1.3 "><p id="EN-US_TOPIC_0000001811610313__a8290bb8428de4ef59dde33e7d71f426d"><a href="dws_04_0578.html">PG_CLASS</a>.oid</p>
</td>
<td class="cellrowborder" valign="top" width="50.94%" headers="mcps1.3.3.2.5.1.4 "><p id="EN-US_TOPIC_0000001811610313__a8ebad6c20d574cadbe0744e02550c6ab">OID of the system catalog the referenced object is in</p>
</td>
</tr>
<tr id="EN-US_TOPIC_0000001811610313__r2d44246a075647e69bb9b3caec633db1"><td class="cellrowborder" valign="top" width="16.16%" headers="mcps1.3.3.2.5.1.1 "><p id="EN-US_TOPIC_0000001811610313__ac5c1265401904babbc52a1d1108b075a">refobjid</p>
</td>
<td class="cellrowborder" valign="top" width="11.28%" headers="mcps1.3.3.2.5.1.2 "><p id="EN-US_TOPIC_0000001811610313__ae6af578cc0ff49a0b7b8b9f57a976dbb">OID</p>
</td>
<td class="cellrowborder" valign="top" width="21.62%" headers="mcps1.3.3.2.5.1.3 "><p id="EN-US_TOPIC_0000001811610313__a7dd63f78310f47c58818f3e6e0bead54">Any OID column</p>
</td>
<td class="cellrowborder" valign="top" width="50.94%" headers="mcps1.3.3.2.5.1.4 "><p id="EN-US_TOPIC_0000001811610313__a60f363b66661414593e07c3f9fc0c97d">OID of the specific referenced object</p>
</td>
</tr>
<tr id="EN-US_TOPIC_0000001811610313__r8890a5e883fa44e4845b740cdb6f8f4d"><td class="cellrowborder" valign="top" width="16.16%" headers="mcps1.3.3.2.5.1.1 "><p id="EN-US_TOPIC_0000001811610313__aae9585ef33264368a1ec5e1d20bdcb96">refobjsubid</p>
</td>
<td class="cellrowborder" valign="top" width="11.28%" headers="mcps1.3.3.2.5.1.2 "><p id="EN-US_TOPIC_0000001811610313__aca4638eefd794354aac246e562d7dc64">Integer</p>
</td>
<td class="cellrowborder" valign="top" width="21.62%" headers="mcps1.3.3.2.5.1.3 "><p id="EN-US_TOPIC_0000001811610313__afd3415f660d843a5997f0fd180574e39">N/A</p>
</td>
<td class="cellrowborder" valign="top" width="50.94%" headers="mcps1.3.3.2.5.1.4 "><p id="EN-US_TOPIC_0000001811610313__af6c8aaf7d31343678969cb3caaaa9432">For a table column, this is the column number (the refobjid and refclassid refer to the table itself). For all other object types, this column is <strong id="EN-US_TOPIC_0000001811610313__b1640815327127">0</strong>.</p>
</td>
</tr>
<tr id="EN-US_TOPIC_0000001811610313__rabbdcdb69c4d4543ae674fa42ffbbce9"><td class="cellrowborder" valign="top" width="16.16%" headers="mcps1.3.3.2.5.1.1 "><p id="EN-US_TOPIC_0000001811610313__a0596cd11eb80475d94fab91acc594773">deptype</p>
</td>
<td class="cellrowborder" valign="top" width="11.28%" headers="mcps1.3.3.2.5.1.2 "><p id="EN-US_TOPIC_0000001811610313__ab8d8e8f6dc994a2981379641c4ae3209">Char</p>
</td>
<td class="cellrowborder" valign="top" width="21.62%" headers="mcps1.3.3.2.5.1.3 "><p id="EN-US_TOPIC_0000001811610313__a278c38f793734204a0032cfc43698d5e">N/A</p>
</td>
<td class="cellrowborder" valign="top" width="50.94%" headers="mcps1.3.3.2.5.1.4 "><p id="EN-US_TOPIC_0000001811610313__afb530153200844159a69c0894ad053fa">A code defining the specific semantics of this dependency relationship</p>
</td>
</tr>
</tbody>
</table>
</div>
<p id="EN-US_TOPIC_0000001811610313__a74c76bfc374040a2810cd8f5ee4dda08">In all cases, a <strong id="EN-US_TOPIC_0000001811610313__b842352706163739">pg_depend</strong> entry indicates that the referenced object cannot be dropped without also dropping the dependent object. However, there are several subflavors defined by <strong id="EN-US_TOPIC_0000001811610313__b1374818375510">deptype</strong>:</p>
<ul id="EN-US_TOPIC_0000001811610313__ua8a164d3386940718750f58e4c1d511b"><li id="EN-US_TOPIC_0000001811610313__lf61c826156984c80bd04e057ef0fc578">DEPENDENCY_NORMAL (n): 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 <strong id="EN-US_TOPIC_0000001811610313__b2729102519712">CASCADE</strong>, in which case the dependent object is dropped, too. Example: a table column has a normal dependency on its data type.</li><li id="EN-US_TOPIC_0000001811610313__lda87eb87916d460fab5f120c7abbd4d7">DEPENDENCY_AUTO (a): The dependent object can be dropped separately from the referenced object, and should be automatically dropped (regardless of RESTRICT or CASCADE mode) if the referenced object is dropped. Example: a named constraint on a table is made autodependent on the table, so that it will go away if the table is dropped.</li><li id="EN-US_TOPIC_0000001811610313__lf044346a0d3048adb5cb8607f73c1e8b">DEPENDENCY_INTERNAL (i): The dependent object was created as part of creation of the referenced object, and is only a part of its internal implementation. A DROP of the dependent object will be disallowed outright (We'll tell the user to issue a DROP against the referenced object, instead). A DROP of the referenced object will be propagated through to drop the dependent object whether CASCADE is specified or not. For example, a trigger used to enforce a foreign key constraint is set to an item internally dependent on its constraint in <a href="dws_04_0580.html">PG_CONSTRAINT</a>.</li><li id="EN-US_TOPIC_0000001811610313__la557dbe687a3467ebb9f5901c3eb4a70">DEPENDENCY_EXTENSION (e): The dependent object is a member of the extension that is the referenced object. (For details, see <a href="dws_04_0589.html">PG_EXTENSION</a>). The dependent object can be dropped via <strong id="EN-US_TOPIC_0000001811610313__b842352706165638">DROP EXTENSION</strong> on the referenced object. Functionally this dependency type acts the same as an internal dependency, but it is kept separate for clarity and to simplify <strong id="EN-US_TOPIC_0000001811610313__b17639331194611">gs_dump</strong>.</li><li id="EN-US_TOPIC_0000001811610313__ld6e5e2aeb50545a88fc03ebb8bd0bf8d">DEPENDENCY_PIN (p): There is no dependent object. This indicates that the system itself depends on the referenced object, and therefore the object cannot be deleted. Entries of this type are created only by <strong id="EN-US_TOPIC_0000001811610313__b842352706165839">initdb</strong>. The columns with dependent object are all zeroes.</li></ul>
<div class="section" id="EN-US_TOPIC_0000001811610313__section1516510274469"><h4 class="sectiontitle">Examples</h4><p id="EN-US_TOPIC_0000001811610313__p62416314469">Query the table that depends on the database object sequence <strong id="EN-US_TOPIC_0000001811610313__b17881153111312">serial1</strong>:</p>
<ol id="EN-US_TOPIC_0000001811610313__ol54695511817"><li id="EN-US_TOPIC_0000001811610313__li13469251184">Query the OID of the sequence <strong id="EN-US_TOPIC_0000001811610313__b6193115011312">serial1</strong> in the system catalog <strong id="EN-US_TOPIC_0000001811610313__b457720101411">PG_CLASS</strong>.<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001811610313__screen135451115102011"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span>
<span class="normal">2</span>
<span class="normal">3</span>
<span class="normal">4</span>
<span class="normal">5</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">SELECT</span><span class="w"> </span><span class="n">oid</span><span class="w"> </span><span class="k">FROM</span><span class="w"> </span><span class="n">pg_class</span><span class="w"> </span><span class="k">WHERE</span><span class="w"> </span><span class="n">relname</span><span class="w"> </span><span class="o">=</span><span class="s1">'serial1'</span><span class="p">;</span>
<span class="n">OID</span>
<span class="c1">-------</span>
<span class="w"> </span><span class="mi">17815</span>
<span class="p">(</span><span class="mi">1</span><span class="w"> </span><span class="k">row</span><span class="p">)</span>
</pre></div></td></tr></table></div>
</div>
</li><li id="EN-US_TOPIC_0000001811610313__li178576139181">Use the system catalog <strong id="EN-US_TOPIC_0000001811610313__b69728551324">PG_DEPEND</strong> and the OID of <strong id="EN-US_TOPIC_0000001811610313__b99519552335">serial1</strong> to obtain the objects that depend on <strong id="EN-US_TOPIC_0000001811610313__b1775814590331">serial1</strong>.<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001811610313__screen201821221209"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span>
<span class="normal">2</span>
<span class="normal">3</span>
<span class="normal">4</span>
<span class="normal">5</span>
<span class="normal">6</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">SELECT</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="k">FROM</span><span class="w"> </span><span class="n">pg_depend</span><span class="w"> </span><span class="k">WHERE</span><span class="w"> </span><span class="n">objid</span><span class="w"> </span><span class="o">=</span><span class="s1">'17815'</span><span class="p">;</span>
<span class="w"> </span><span class="n">classid</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">objid</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">objsubid</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">refclassid</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">refobjid</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">refobjsubid</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">deptype</span>
<span class="c1">---------+-------+----------+------------+----------+-------------+---------</span>
<span class="w"> </span><span class="mi">1259</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="mi">17815</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="mi">0</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="mi">2615</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="mi">2200</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="mi">0</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">n</span>
<span class="w"> </span><span class="mi">1259</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="mi">17815</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="mi">0</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="mi">1259</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="mi">17812</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="mi">1</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">a</span>
<span class="p">(</span><span class="mi">2</span><span class="w"> </span><span class="k">rows</span><span class="p">)</span>
</pre></div></td></tr></table></div>
</div>
</li><li id="EN-US_TOPIC_0000001811610313__li1581165143110">Obtain the OID of the table that depends on the serial1 sequence based on the refobjid field and query the table name. The result indicates that the table <strong id="EN-US_TOPIC_0000001811610313__b77611456203515">customer_address</strong> depends on <strong id="EN-US_TOPIC_0000001811610313__b3651111163613">serial1</strong>.<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001811610313__screen124261031857"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span>
<span class="normal">2</span>
<span class="normal">3</span>
<span class="normal">4</span>
<span class="normal">5</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">SELECT</span><span class="w"> </span><span class="n">relname</span><span class="w"> </span><span class="k">FROM</span><span class="w"> </span><span class="n">pg_class</span><span class="w"> </span><span class="k">where</span><span class="w"> </span><span class="n">oid</span><span class="o">=</span><span class="s1">'17812'</span><span class="p">;</span>
<span class="w"> </span><span class="n">relname</span>
<span class="c1">------------------</span>
<span class="w"> </span><span class="n">customer_address</span>
<span class="p">(</span><span class="mi">1</span><span class="w"> </span><span class="k">row</span><span class="p">)</span>
</pre></div></td></tr></table></div>
</div>
</li></ol>
</div>
</div>
<div>
<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="dws_04_0561.html">System Catalogs</a></div>
</div>
</div>
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