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doc-exports/docs/dws/tool/dws_16_0163.html
luhuayi a5e3903f6b DWS TG 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>
2025-04-23 13:53:01 +00:00

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<a name="EN-US_TOPIC_0000001860198673"></a><a name="EN-US_TOPIC_0000001860198673"></a>
<h1 class="topictitle1">Renaming a Column</h1>
<div id="body8662426"><div class="section" id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_section11961234133818"><h4 class="sectiontitle">Using a Reserved Keyword As a Column Name</h4><p id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_p68161834113915">In GaussDB(DWS), reserved keywords must be enclosed in double quotation marks when they are used as column names. The following reserved keywords are supported: desc, checksum, operator, and size.</p>
<p id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_p1449419509418"><strong id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_b146981227428">Input</strong></p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_screen188983454319"><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></pre></div></td><td class="code"><div><pre><span></span><span class="k">CREATE</span><span class="w"> </span><span class="k">TABLE</span><span class="w"> </span><span class="o">`</span><span class="k">desc</span><span class="o">`</span><span class="w"> </span><span class="p">(</span>
<span class="w"> </span><span class="k">user</span><span class="w"> </span><span class="nb">char</span><span class="p">,</span>
<span class="w"> </span><span class="n">checksum</span><span class="w"> </span><span class="nb">int</span><span class="p">,</span>
<span class="w"> </span><span class="k">operator</span><span class="w"> </span><span class="nb">smallint</span><span class="p">,</span>
<span class="w"> </span><span class="k">desc</span><span class="w"> </span><span class="nb">char</span><span class="p">,</span>
<span class="w"> </span><span class="k">size</span><span class="w"> </span><span class="nb">bigint</span>
<span class="p">);</span>
</pre></div></td></tr></table></div>
</div>
<p id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_p439699164315"><strong id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_b1874825164318">Output</strong></p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_screen147551719194316"><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></pre></div></td><td class="code"><div><pre><span></span><span class="k">CREATE</span><span class="w"> </span><span class="k">TABLE</span><span class="w"> </span><span class="ss">&quot;public&quot;</span><span class="p">.</span><span class="ss">&quot;desc&quot;</span><span class="w"> </span><span class="p">(</span>
<span class="w"> </span><span class="ss">&quot;user&quot;</span><span class="w"> </span><span class="nb">CHAR</span><span class="p">(</span><span class="mi">4</span><span class="p">),</span>
<span class="w"> </span><span class="ss">&quot;checksum&quot;</span><span class="w"> </span><span class="nb">INTEGER</span><span class="p">,</span>
<span class="w"> </span><span class="ss">&quot;operator&quot;</span><span class="w"> </span><span class="nb">SMALLINT</span><span class="p">,</span>
<span class="w"> </span><span class="ss">&quot;desc&quot;</span><span class="w"> </span><span class="nb">CHAR</span><span class="p">(</span><span class="mi">4</span><span class="p">),</span>
<span class="w"> </span><span class="ss">&quot;size&quot;</span><span class="w"> </span><span class="nb">BIGINT</span>
<span class="p">)</span><span class="w"> </span><span class="k">WITH</span><span class="w"> </span><span class="p">(</span><span class="n">ORIENTATION</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">ROW</span><span class="p">,</span><span class="w"> </span><span class="n">COMPRESSION</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">NO</span><span class="p">)</span><span class="w"> </span><span class="n">NOCOMPRESS</span><span class="w"> </span><span class="n">DISTRIBUTE</span><span class="w"> </span><span class="k">BY</span><span class="w"> </span><span class="n">HASH</span><span class="w"> </span><span class="p">(</span><span class="ss">&quot;user&quot;</span><span class="p">);</span>
</pre></div></td></tr></table></div>
</div>
</div>
<div class="section" id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_section1840153763916"><h4 class="sectiontitle">Using the Name of a Hidden Column of a System Catalog As a Column Name</h4><p id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_p191614582394">If the defined column name is the same as that of a hidden column in a GaussDB(DWS) system catalog ( including <strong id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_b128369149179">xc_node_id</strong> and <strong id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_b101941219181714">tableoid</strong>, <strong id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_b103432213171">cmax</strong>, <strong id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_b6308424161711">xmax</strong>, <strong id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_b16581172617178">cmin</strong>, <strong id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_b10122182915174">xmin</strong>, <strong id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_b1956914327176">ctid</strong>, <strong id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_b174638364179">tid.</strong>), you need to rename the column. To rename the column, add <strong id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_b4348435174">_new</strong> at the end. For example, change <strong id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_b1739314651810">xc_node_id</strong> to <strong id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_b3360181013183">xc_node_id_new</strong>.</p>
<p id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_p712835684417"><strong id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_b11771161610455">Input</strong></p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_screen964739124513"><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></pre></div></td><td class="code"><div><pre><span></span><span class="k">DROP</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="o">`</span><span class="n">renameFieldName</span><span class="o">`</span><span class="p">;</span>
<span class="k">CREATE</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">NOT</span><span class="w"> </span><span class="k">EXISTS</span><span class="w"> </span><span class="o">`</span><span class="n">renameFieldName</span><span class="o">`</span><span class="p">(</span>
<span class="w"> </span><span class="n">xc_node_id</span><span class="w"> </span><span class="nb">int</span><span class="p">,</span>
<span class="w"> </span><span class="n">tableoid</span><span class="w"> </span><span class="nb">char</span><span class="p">(</span><span class="mi">3</span><span class="p">),</span>
<span class="w"> </span><span class="n">cmax</span><span class="w"> </span><span class="nb">smallint</span><span class="p">,</span>
<span class="w"> </span><span class="n">xmax</span><span class="w"> </span><span class="nb">bigint</span><span class="w"> </span><span class="n">auto_increment</span><span class="p">,</span>
<span class="w"> </span><span class="n">cmin</span><span class="w"> </span><span class="nb">varchar</span><span class="p">(</span><span class="mi">10</span><span class="p">),</span>
<span class="w"> </span><span class="n">xmin</span><span class="w"> </span><span class="nb">int</span><span class="p">,</span>
<span class="w"> </span><span class="n">ctid</span><span class="w"> </span><span class="nb">int</span><span class="w"> </span><span class="n">auto_increment</span><span class="p">,</span>
<span class="w"> </span><span class="n">tid</span><span class="w"> </span><span class="nb">int</span>
<span class="p">);</span>
<span class="k">DROP</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="o">`</span><span class="n">renameFieldName</span><span class="o">`</span><span class="p">;</span>
</pre></div></td></tr></table></div>
</div>
<p id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_p981414459"><strong id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_b843718195457">Output</strong></p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001860198673__en-us_topic_0000001397279084_screen1156413104513"><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></pre></div></td><td class="code"><div><pre><span></span><span class="k">DROP</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="ss">&quot;public&quot;</span><span class="p">.</span><span class="ss">&quot;renamefieldname&quot;</span><span class="p">;</span>
<span class="k">CREATE</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">NOT</span><span class="w"> </span><span class="k">EXISTS</span><span class="w"> </span><span class="ss">&quot;public&quot;</span><span class="p">.</span><span class="ss">&quot;renamefieldname&quot;</span><span class="w"> </span><span class="p">(</span>
<span class="w"> </span><span class="ss">&quot;xc_node_id_new&quot;</span><span class="w"> </span><span class="nb">INTEGER</span><span class="p">,</span>
<span class="w"> </span><span class="ss">&quot;tableoid_new&quot;</span><span class="w"> </span><span class="nb">CHAR</span><span class="p">(</span><span class="mi">12</span><span class="p">),</span>
<span class="w"> </span><span class="ss">&quot;cmax_new&quot;</span><span class="w"> </span><span class="nb">SMALLINT</span><span class="p">,</span>
<span class="w"> </span><span class="ss">&quot;xmax_new&quot;</span><span class="w"> </span><span class="n">BIGSERIAL</span><span class="p">,</span>
<span class="w"> </span><span class="ss">&quot;cmin_new&quot;</span><span class="w"> </span><span class="nb">VARCHAR</span><span class="p">(</span><span class="mi">40</span><span class="p">),</span>
<span class="w"> </span><span class="ss">&quot;xmin_new&quot;</span><span class="w"> </span><span class="nb">INTEGER</span><span class="p">,</span>
<span class="w"> </span><span class="ss">&quot;ctid_new&quot;</span><span class="w"> </span><span class="nb">SERIAL</span><span class="p">,</span>
<span class="w"> </span><span class="ss">&quot;tid_new&quot;</span><span class="w"> </span><span class="nb">INTEGER</span>
<span class="p">)</span><span class="w"> </span><span class="k">WITH</span><span class="w"> </span><span class="p">(</span><span class="n">ORIENTATION</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">ROW</span><span class="p">,</span><span class="w"> </span><span class="n">COMPRESSION</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">NO</span><span class="p">)</span><span class="w"> </span><span class="n">NOCOMPRESS</span><span class="w"> </span><span class="n">DISTRIBUTE</span><span class="w"> </span><span class="k">BY</span><span class="w"> </span><span class="n">HASH</span><span class="w"> </span><span class="p">(</span><span class="ss">&quot;xc_node_id_new&quot;</span><span class="p">);</span>
<span class="k">DROP</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="ss">&quot;public&quot;</span><span class="p">.</span><span class="ss">&quot;renamefieldname&quot;</span><span class="p">;</span>
</pre></div></td></tr></table></div>
</div>
</div>
</div>
<div>
<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="dws_16_0119.html">Table (Optional Parameters and Operations)</a></div>
</div>
</div>
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