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Lu, Huayi e6fa411af0 DWS DEV 830.201 version 
Reviewed-by: Pruthi, Vineet <vineet.pruthi@t-systems.com>
Co-authored-by: Lu, Huayi <luhuayi@huawei.com>
Co-committed-by: Lu, Huayi <luhuayi@huawei.com>
2024-05-16 07:24:04 +00:00

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<a name="EN-US_TOPIC_0000001233708669"></a><a name="EN-US_TOPIC_0000001233708669"></a>
<h1 class="topictitle1">ALTER FOREIGN TABLE (SQL on other <span id="text524316715">GaussDB(DWS)</span>)</h1>
<div id="body1546826781595"><div class="section" id="EN-US_TOPIC_0000001233708669__s57d9dea5dbcc42f99062788434d82299"><h4 class="sectiontitle">Function</h4><p id="EN-US_TOPIC_0000001233708669__a47d757137be04837825173873fee3169"><strong id="EN-US_TOPIC_0000001233708669__b18338431203510">ALTER FOREIGN TABLE</strong> modifies a foreign table in associated analysis.</p>
</div>
<div class="section" id="EN-US_TOPIC_0000001233708669__s861dac7b5c7540e981f240b4e2052507"><h4 class="sectiontitle">Precautions</h4><p id="EN-US_TOPIC_0000001233708669__a77d15996bd3441748940cf27e467f3c7">None</p>
</div>
<div class="section" id="EN-US_TOPIC_0000001233708669__s3bdb4f4f0c5e46f9a35c5474f6f70328"><h4 class="sectiontitle">Syntax</h4><ul id="EN-US_TOPIC_0000001233708669__u422e1e0147eb4c56bff87df31e45fe64"><li id="EN-US_TOPIC_0000001233708669__li6231005817">Set a foreign table's attributes:<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001233708669__screen2698157143714"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span>
<span class="normal">2</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">ALTER</span><span class="w"> </span><span class="k">FOREIGN</span><span class="w"> </span><span class="k">TABLE</span><span class="w"> </span><span class="p">[</span><span class="w"> </span><span class="k">IF</span><span class="w"> </span><span class="k">EXISTS</span><span class="w"> </span><span class="p">]</span><span class="w"> </span><span class="n">tablename</span>
<span class="w"> </span><span class="k">OPTIONS</span><span class="w"> </span><span class="p">(</span><span class="w"> </span><span class="err">{</span><span class="p">[</span><span class="w"> </span><span class="k">SET</span><span class="w"> </span><span class="p">]</span><span class="w"> </span><span class="k">option</span><span class="w"> </span><span class="p">[</span><span class="s1">'value'</span><span class="p">]</span><span class="err">}</span><span class="w"> </span><span class="p">[,</span><span class="w"> </span><span class="p">...</span><span class="w"> </span><span class="p">]);</span>
</pre></div></td></tr></table></div>
</div>
</li><li id="EN-US_TOPIC_0000001233708669__lfe824ba5ff7d4542b622906e7b55e254">Set the owner of the foreign table:<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001233708669__s966b3a866d70485aba4c008f698b25d9"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span>
<span class="normal">2</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">ALTER</span><span class="w"> </span><span class="k">FOREIGN</span><span class="w"> </span><span class="k">TABLE</span><span class="w"> </span><span class="p">[</span><span class="w"> </span><span class="k">IF</span><span class="w"> </span><span class="k">EXISTS</span><span class="w"> </span><span class="p">]</span><span class="w"> </span><span class="n">tablename</span><span class="w"> </span>
<span class="w"> </span><span class="k">OWNER</span><span class="w"> </span><span class="k">TO</span><span class="w"> </span><span class="n">new_owner</span><span class="p">;</span>
</pre></div></td></tr></table></div>
</div>
</li></ul>
<ul id="EN-US_TOPIC_0000001233708669__u7fc1210afd50402386666da17bec66cf"><li id="EN-US_TOPIC_0000001233708669__li5444528112915">Update the type of a foreign table column:<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001233708669__screen844715418294"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span>
<span class="normal">2</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">ALTER</span><span class="w"> </span><span class="k">FOREIGN</span><span class="w"> </span><span class="k">TABLE</span><span class="w"> </span><span class="p">[</span><span class="w"> </span><span class="k">IF</span><span class="w"> </span><span class="k">EXISTS</span><span class="w"> </span><span class="p">]</span><span class="w"> </span><span class="k">table_name</span>
<span class="w"> </span><span class="k">MODIFY</span><span class="w"> </span><span class="p">(</span><span class="w"> </span><span class="err">{</span><span class="w"> </span><span class="k">column_name</span><span class="w"> </span><span class="n">data_type</span><span class="w"> </span><span class="p">[,</span><span class="w"> </span><span class="p">...]</span><span class="w"> </span><span class="err">}</span><span class="w"> </span><span class="p">);</span>
</pre></div></td></tr></table></div>
</div>
</li><li id="EN-US_TOPIC_0000001233708669__lbf72c4436dc44e1a9121a763cbbd1933">Modify the column of the foreign table:<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001233708669__sa78ca5c3396246ecab4037da344b190d"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span>
<span class="normal">2</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">ALTER</span><span class="w"> </span><span class="k">FOREIGN</span><span class="w"> </span><span class="k">TABLE</span><span class="w"> </span><span class="p">[</span><span class="w"> </span><span class="k">IF</span><span class="w"> </span><span class="k">EXISTS</span><span class="w"> </span><span class="p">]</span><span class="w"> </span><span class="n">tablename</span><span class="w"> </span>
<span class="w"> </span><span class="n">action</span><span class="w"> </span><span class="p">[,</span><span class="w"> </span><span class="p">...</span><span class="w"> </span><span class="p">];</span>
</pre></div></td></tr></table></div>
</div>
<div class="p" id="EN-US_TOPIC_0000001233708669__ad4db2804f12342ecbafd9a80ebfd839e">The <strong id="EN-US_TOPIC_0000001233708669__b842352706151610">action</strong> syntax is as follows:<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001233708669__se1721bacc9994f758f0c887baf765aef"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span>
<span class="normal">2</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">ALTER</span><span class="w"> </span><span class="p">[</span><span class="w"> </span><span class="k">COLUMN</span><span class="w"> </span><span class="p">]</span><span class="w"> </span><span class="k">column_name</span><span class="w"> </span><span class="p">[</span><span class="w"> </span><span class="k">SET</span><span class="w"> </span><span class="k">DATA</span><span class="w"> </span><span class="p">]</span><span class="w"> </span><span class="k">TYPE</span><span class="w"> </span><span class="n">data_type</span>
<span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="k">MODIFY</span><span class="w"> </span><span class="k">column_name</span><span class="w"> </span><span class="n">data_type</span>
</pre></div></td></tr></table></div>
</div>
</div>
<p id="EN-US_TOPIC_0000001233708669__a1599ea094fec4833b43a542a8191fb4f">For details, see <a href="dws_06_0142.html">ALTER TABLE</a>.</p>
</li></ul>
</div>
<div class="section" id="EN-US_TOPIC_0000001233708669__s8d3b0090816744e0930e0822d5fecf52"><h4 class="sectiontitle">Parameter Description</h4><ul id="EN-US_TOPIC_0000001233708669__u2e3e97100b674198861630b36097eea3"><li id="EN-US_TOPIC_0000001233708669__lc090ec05ae614b80bb9a948ff687df30"><strong id="EN-US_TOPIC_0000001233708669__a4f5e121e8fd44f13b17b8ca1f0baf56e">IF EXISTS</strong><p id="EN-US_TOPIC_0000001233708669__a946799bc5a344c06a13bc7eaafb69f3a">Sends a notification instead of an error if no tables have identical names. The notification prompts that the table you are querying does not exist.</p>
</li><li id="EN-US_TOPIC_0000001233708669__l4c856c90264e468d9da12896cbc1c9bd"><strong id="EN-US_TOPIC_0000001233708669__a9fe2c3d20fcc4f46ae16956951a19b57">tablename</strong><p id="EN-US_TOPIC_0000001233708669__a3c0e0a8fd76c470b8ce3adea09458b04">Specifies the name of an existing foreign table to be modified.</p>
<p id="EN-US_TOPIC_0000001233708669__a228f763fd7294819bf1b8ae4c4e6b271">Value range: an existing foreign table name</p>
</li><li id="EN-US_TOPIC_0000001233708669__la431a241fb884e978368fac8ae651cb8"><strong id="EN-US_TOPIC_0000001233708669__a2956e43b807e4d8c8678c6fc21d1eb7d">new_owner</strong><p id="EN-US_TOPIC_0000001233708669__aef96857125184eb0bc1148614f0cef26">Specifies the new owner of the foreign table.</p>
<p id="EN-US_TOPIC_0000001233708669__a382c49b508a1408191caac61acb7b374">Value range: a string indicating a valid user name</p>
</li><li id="EN-US_TOPIC_0000001233708669__l60a667e05b4a4e338ad57c6893d0b29c"><strong id="EN-US_TOPIC_0000001233708669__a139964500cdf4867bc88b79536e5723d">data_type</strong><p id="EN-US_TOPIC_0000001233708669__abaffb1368e444d87bfa3ddffe400ed17">Specifies the new type for an existing column.</p>
<p id="EN-US_TOPIC_0000001233708669__aaa50010abd8044599f8ce6008745d607">Value range: a string compliant with the identifier naming rules</p>
</li><li id="EN-US_TOPIC_0000001233708669__l7934fd585bab45fab0ae1de3ad4f852f"><strong id="EN-US_TOPIC_0000001233708669__a71bd69b0d3924157b2b72dc56ec3cad7">column_name</strong><p id="EN-US_TOPIC_0000001233708669__a75d114e97f434d58aa4e18d9f158ed35">Specifies the name of an existing column.</p>
<p id="EN-US_TOPIC_0000001233708669__adcf3931271674d37b5526c4615db3d23">Value range: a string. It must comply with the naming convention.</p>
</li></ul>
<p id="EN-US_TOPIC_0000001233708669__a382eb5a22139409093f2df1c223000d0">For details on how to modify other parameters in the foreign table, see <a href="dws_06_0142.html#EN-US_TOPIC_0000001188588994__s3e87132692794964b56e3ba420e7b544">Parameter Description</a> in <strong id="EN-US_TOPIC_0000001233708669__b97081168308">ALTER TABLE</strong>.</p>
</div>
<div class="section" id="EN-US_TOPIC_0000001233708669__s8302a739997543e0a22f9ee43ce9bfbf"><h4 class="sectiontitle">Example:</h4><ol id="EN-US_TOPIC_0000001233708669__ol137946171418"><li id="EN-US_TOPIC_0000001233708669__li1431516612">Create a foreign server named <strong id="EN-US_TOPIC_0000001233708669__b198220622882657">server_remote</strong>. The corresponding foreign data wrapper is <strong id="EN-US_TOPIC_0000001233708669__b29029669182657">GC_FDW</strong>.<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001233708669__s0211efd2605f4c1b9bc7189580006ca8"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">CREATE</span><span class="w"> </span><span class="n">SERVER</span><span class="w"> </span><span class="n">server_remote</span><span class="w"> </span><span class="k">FOREIGN</span><span class="w"> </span><span class="k">DATA</span><span class="w"> </span><span class="n">WRAPPER</span><span class="w"> </span><span class="n">GC_FDW</span><span class="w"> </span><span class="k">OPTIONS</span><span class="w"> </span><span class="p">(</span><span class="n">address</span><span class="w"> </span><span class="s1">'10.10.0.100:25000,10.10.0.101:25000'</span><span class="p">,</span><span class="n">dbname</span><span class="w"> </span><span class="s1">'test'</span><span class="p">,</span><span class="w"> </span><span class="n">username</span><span class="w"> </span><span class="s1">'test'</span><span class="p">,</span><span class="w"> </span><span class="n">password</span><span class="w"> </span><span class="s1">'{Password}'</span><span class="p">);</span>
</pre></div></td></tr></table></div>
</div>
</li><li id="EN-US_TOPIC_0000001233708669__li197931522315">Create a foreign table named <strong id="EN-US_TOPIC_0000001233708669__b15165996782657">region</strong>.<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001233708669__sd926eb1a47c646f089d22960d0e4bfaf"><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>
<span class="normal"> 7</span>
<span class="normal"> 8</span>
<span class="normal"> 9</span>
<span class="normal">10</span>
<span class="normal">11</span>
<span class="normal">12</span>
<span class="normal">13</span>
<span class="normal">14</span>
<span class="normal">15</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">DROP</span><span class="w"> </span><span class="k">FOREIGN</span><span class="w"> </span><span class="k">TABLE</span><span class="w"> </span><span class="k">IF</span><span class="w"> </span><span class="k">EXISTS</span><span class="w"> </span><span class="n">region</span><span class="p">;</span>
<span class="k">CREATE</span><span class="w"> </span><span class="k">FOREIGN</span><span class="w"> </span><span class="k">TABLE</span><span class="w"> </span><span class="n">region</span>
<span class="p">(</span>
<span class="w"> </span><span class="n">R_REGIONKEY</span><span class="w"> </span><span class="n">INT4</span><span class="p">,</span>
<span class="w"> </span><span class="n">R_NAME</span><span class="w"> </span><span class="nb">TEXT</span><span class="p">,</span>
<span class="w"> </span><span class="n">R_COMMENT</span><span class="w"> </span><span class="nb">TEXT</span>
<span class="p">)</span>
<span class="n">SERVER</span>
<span class="w"> </span><span class="n">server_remote</span>
<span class="k">OPTIONS</span>
<span class="p">(</span>
<span class="w"> </span><span class="k">schema_name</span><span class="w"> </span><span class="s1">'test'</span><span class="p">,</span>
<span class="w"> </span><span class="k">table_name</span><span class="w"> </span><span class="s1">'region'</span><span class="p">,</span>
<span class="w"> </span><span class="k">encoding</span><span class="w"> </span><span class="s1">'gbk'</span>
<span class="p">);</span>
</pre></div></td></tr></table></div>
</div>
</li><li id="EN-US_TOPIC_0000001233708669__li1383692141513">Modify the <strong id="EN-US_TOPIC_0000001233708669__b53206055182657">region</strong> option of the foreign table.<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001233708669__sa9ac0c08bc1f43158b422d0124578c2d"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">ALTER</span><span class="w"> </span><span class="k">FOREIGN</span><span class="w"> </span><span class="k">TABLE</span><span class="w"> </span><span class="n">region</span><span class="w"> </span><span class="k">OPTIONS</span><span class="w"> </span><span class="p">(</span><span class="k">SET</span><span class="w"> </span><span class="k">schema_name</span><span class="w"> </span><span class="s1">'test'</span><span class="p">);</span>
</pre></div></td></tr></table></div>
</div>
</li><li id="EN-US_TOPIC_0000001233708669__li441762413156">Change the type of the <strong id="EN-US_TOPIC_0000001233708669__b56992819933425">r_name</strong> column to <strong id="EN-US_TOPIC_0000001233708669__b65747483933425">text</strong> in the <strong id="EN-US_TOPIC_0000001233708669__b202716600133425">region</strong> foreign table.<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001233708669__screen153383711284"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">ALTER</span><span class="w"> </span><span class="k">FOREIGN</span><span class="w"> </span><span class="k">TABLE</span><span class="w"> </span><span class="n">region</span><span class="w"> </span><span class="k">ALTER</span><span class="w"> </span><span class="n">r_name</span><span class="w"> </span><span class="k">TYPE</span><span class="w"> </span><span class="nb">TEXT</span><span class="p">;</span>
</pre></div></td></tr></table></div>
</div>
</li></ol>
</div>
<div class="section" id="EN-US_TOPIC_0000001233708669__s1d9765c9720a460b8998648bc43a7744"><h4 class="sectiontitle">Helpful Links</h4><p id="EN-US_TOPIC_0000001233708669__a7c561b868acc4347abaf995a4278a1a0"><a href="dws_06_0192.html">DROP FOREIGN TABLE</a>, <a href="dws_06_0162.html">CREATE FOREIGN TABLE (SQL on other GaussDB(DWS))</a></p>
</div>
</div>
<div>
<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="dws_06_0118.html">DDL Syntax</a></div>
</div>
</div>
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