forked from docs/doc-exports
luhuayi
a5e3903f6b
Reviewed-by: Pruthi, Vineet <vineet.pruthi@t-systems.com> Co-authored-by: luhuayi <luhuayi@huawei.com> Co-committed-by: luhuayi <luhuayi@huawei.com>
56 lines
7.9 KiB
HTML
56 lines
7.9 KiB
HTML
<a name="EN-US_TOPIC_0000001813598904"></a><a name="EN-US_TOPIC_0000001813598904"></a>
|
|
|
|
<h1 class="topictitle1">COMMENT</h1>
|
|
<div id="body8662426"><p id="EN-US_TOPIC_0000001813598904__en-us_topic_0000001436175729_en-us_topic_0214164629_p781310512108">In MySQL, <strong id="EN-US_TOPIC_0000001813598904__en-us_topic_0000001436175729_b124908102831644">COMMENT</strong> is a comment for a table. In GaussDB(DWS), this attribute can be used to modify table definition. During migration using DSC, additional table attribute information is added.</p>
|
|
<p id="EN-US_TOPIC_0000001813598904__en-us_topic_0000001436175729_en-us_topic_0214164629_p659017367411"><strong id="EN-US_TOPIC_0000001813598904__en-us_topic_0000001436175729_en-us_topic_0214164629_b594718313141">Input</strong></p>
|
|
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001813598904__en-us_topic_0000001436175729_en-us_topic_0214164629_screen260412397186"><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></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">public</span><span class="o">`</span><span class="p">.</span><span class="o">`</span><span class="n">runoob_alter_test</span><span class="o">`</span><span class="p">(</span>
|
|
<span class="w"> </span><span class="o">`</span><span class="n">dataType1</span><span class="o">`</span><span class="w"> </span><span class="nb">int</span><span class="w"> </span><span class="k">NOT</span><span class="w"> </span><span class="k">NULL</span><span class="w"> </span><span class="n">AUTO_INCREMENT</span><span class="p">,</span>
|
|
<span class="o">`</span><span class="n">dataType2</span><span class="o">`</span><span class="w"> </span><span class="nb">FLOAT</span><span class="w"> </span><span class="p">(</span><span class="mi">10</span><span class="p">,</span><span class="mi">2</span><span class="p">)</span><span class="w"> </span><span class="k">COMMENT</span><span class="s1">'dataType2 column'</span><span class="p">,</span>
|
|
<span class="w"> </span><span class="k">PRIMARY</span><span class="w"> </span><span class="k">KEY</span><span class="p">(</span><span class="o">`</span><span class="n">dataType1</span><span class="o">`</span><span class="p">)</span>
|
|
<span class="p">)</span><span class="w"> </span><span class="k">comment</span><span class="o">=</span><span class="s1">'table comment'</span><span class="p">;</span><span class="w"> </span>
|
|
|
|
<span class="k">ALTER</span><span class="w"> </span><span class="k">TABLE</span><span class="w"> </span><span class="o">`</span><span class="k">public</span><span class="o">`</span><span class="p">.</span><span class="o">`</span><span class="n">runoob_alter_test</span><span class="o">`</span><span class="w"> </span><span class="k">COMMENT</span><span class="w"> </span><span class="s1">'table comment after modification'</span><span class="p">;</span>
|
|
<span class="k">ALTER</span><span class="w"> </span><span class="k">TABLE</span><span class="w"> </span><span class="o">`</span><span class="k">public</span><span class="o">`</span><span class="p">.</span><span class="o">`</span><span class="n">runoob_alter_test</span><span class="o">`</span><span class="w"> </span><span class="k">ADD</span><span class="w"> </span><span class="k">INDEX</span><span class="w"> </span><span class="n">age_index</span><span class="p">(</span><span class="n">dataType2</span><span class="p">)</span><span class="w"> </span><span class="k">COMMENT</span><span class="s1">' index'</span><span class="p">;</span>
|
|
</pre></div></td></tr></table></div>
|
|
</div>
|
|
<p id="EN-US_TOPIC_0000001813598904__en-us_topic_0000001436175729_en-us_topic_0214164629_p12114173518210"><strong id="EN-US_TOPIC_0000001813598904__en-us_topic_0000001436175729_en-us_topic_0214164629_b1871046151416">Output</strong></p>
|
|
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001813598904__en-us_topic_0000001436175729_en-us_topic_0214164629_screen489081782010"><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">CREATE</span><span class="w"> </span><span class="k">TABLE</span><span class="w"> </span><span class="ss">"public"</span><span class="p">.</span><span class="ss">"runoob_alter_test"</span>
|
|
<span class="p">(</span>
|
|
<span class="w"> </span><span class="ss">"datatype1"</span><span class="w"> </span><span class="nb">SERIAL</span><span class="w"> </span><span class="k">NOT</span><span class="w"> </span><span class="k">NULL</span><span class="p">,</span>
|
|
<span class="ss">"datatype2"</span><span class="w"> </span><span class="nb">REAL</span><span class="w"> </span><span class="k">COMMENT</span><span class="w"> </span><span class="s1">'dataType2 column'</span><span class="p">,</span>
|
|
<span class="w"> </span><span class="k">PRIMARY</span><span class="w"> </span><span class="k">KEY</span><span class="w"> </span><span class="p">(</span><span class="ss">"datatype1"</span><span class="p">)</span>
|
|
<span class="p">)</span>
|
|
<span class="w"> </span><span class="k">WITH</span><span class="w"> </span><span class="p">(</span><span class="w"> </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="w"> </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">"datatype1"</span><span class="p">)</span>
|
|
<span class="k">COMMENT</span><span class="w"> </span><span class="s1">'Comment of the table'</span><span class="p">;</span>
|
|
<span class="k">ALTER</span><span class="w"> </span><span class="k">TABLE</span><span class="w"> </span><span class="o">`</span><span class="k">public</span><span class="o">`</span><span class="p">.</span><span class="o">`</span><span class="n">runoob_alter_test</span><span class="o">`</span><span class="w"> </span><span class="k">COMMENT</span><span class="w"> </span><span class="s1">'table comment after modification'</span><span class="p">;</span>
|
|
<span class="k">CREATE</span><span class="w"> </span><span class="k">INDEX</span><span class="w"> </span><span class="ss">"age_index"</span><span class="w"> </span><span class="k">ON</span><span class="w"> </span><span class="ss">"public"</span><span class="p">.</span><span class="ss">"runoob_alter_test"</span><span class="w"> </span><span class="p">(</span><span class="ss">"dataType2"</span><span class="p">)</span><span class="w"> </span><span class="k">COMMENT</span><span class="s1">' index'</span><span class="p">;</span>
|
|
</pre></div></td></tr></table></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>
|
|
|