forked from docs/doc-exports
Lu, Huayi
27019c2991
Reviewed-by: Hasko, Vladimir <vladimir.hasko@t-systems.com> 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>
54 lines
3.5 KiB
HTML
54 lines
3.5 KiB
HTML
<a name="EN-US_TOPIC_0000001772696208"></a><a name="EN-US_TOPIC_0000001772696208"></a>
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<h1 class="topictitle1">SET|DROP COLUMN DEFAULT VALUE</h1>
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<div id="body8662426"><p id="EN-US_TOPIC_0000001772696208__en-us_topic_0000001658024998_en-us_topic_0000001435815993_en-us_topic_0214164473_p19751438112911">In MySQL, the <strong id="EN-US_TOPIC_0000001772696208__en-us_topic_0000001658024998_en-us_topic_0000001435815993_b76789567731815">COLUMN</strong> keyword can be omitted when the <strong id="EN-US_TOPIC_0000001772696208__en-us_topic_0000001658024998_en-us_topic_0000001435815993_b137507849131815">ALTER</strong> statement is used to set the default value of a column. DSC will perform adaptation based on GaussDB(DWS) features during migration.</p>
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<p id="EN-US_TOPIC_0000001772696208__en-us_topic_0000001658024998_en-us_topic_0000001435815993_en-us_topic_0214164473_p8060118"><strong id="EN-US_TOPIC_0000001772696208__en-us_topic_0000001658024998_en-us_topic_0000001435815993_en-us_topic_0214164473_b20727929204011">Input</strong></p>
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<pre class="screen" id="EN-US_TOPIC_0000001772696208__en-us_topic_0000001658024998_en-us_topic_0000001435815993_en-us_topic_0214164473_screen173026529304">CREATE TABLE IF NOT EXISTS `runoob_alter_test`(
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`dataType1` int NOT NULL AUTO_INCREMENT,
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`dataType2` FLOAT(10,2),
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`dataType3` DOUBLE(20,8),
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`dataType4` TEXT NOT NULL,
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`dataType5` YEAR NOT NULL DEFAULT '2018',
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`dataType6` DATETIME NOT NULL DEFAULT '2018-10-12 15:27:33.999999',
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`dataType7` CHAR NOT NULL DEFAULT '',
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`dataType8` VARCHAR(50),
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`dataType9` VARCHAR(50) NOT NULL DEFAULT '',
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`dataType10` TIME NOT NULL DEFAULT '10:20:59',
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PRIMARY KEY(`dataType1`)
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)ENGINE=InnoDB DEFAULT CHARSET=utf8;
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ALTER TABLE runoob_alter_test ALTER dataType2 SET DEFAULT 1;
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ALTER TABLE runoob_alter_test ALTER COLUMN dataType2 SET DEFAULT 3;
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ALTER TABLE runoob_alter_test ALTER dataType2 DROP DEFAULT;
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ALTER TABLE runoob_alter_test ALTER COLUMN dataType2 DROP DEFAULT;</pre>
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<p id="EN-US_TOPIC_0000001772696208__en-us_topic_0000001658024998_en-us_topic_0000001435815993_en-us_topic_0214164473_p1431826173714"><strong id="EN-US_TOPIC_0000001772696208__en-us_topic_0000001658024998_en-us_topic_0000001435815993_en-us_topic_0214164473_b11199142516406">Output</strong></p>
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<pre class="screen" id="EN-US_TOPIC_0000001772696208__en-us_topic_0000001658024998_en-us_topic_0000001435815993_en-us_topic_0214164473_screen18665125423015">CREATE TABLE IF NOT EXISTS "public"."runoob_alter_test"
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(
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"datatype1" SERIAL NOT NULL,
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"datatype2" REAL,
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"datatype3" DOUBLE PRECISION,
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"datatype4" TEXT NOT NULL,
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"datatype5" SMALLINT NOT NULL DEFAULT '2018',
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"datatype6" TIMESTAMP WITHOUT TIME ZONE NOT NULL DEFAULT '2018-10-12 15:27:33.999999',
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"datatype7" CHAR(4) NOT NULL DEFAULT '',
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"datatype8" VARCHAR(200),
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"datatype9" VARCHAR(200) NOT NULL DEFAULT '',
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"datatype10" TIME WITHOUT TIME ZONE NOT NULL DEFAULT '10:20:59',
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PRIMARY KEY ("datatype1")
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)
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WITH ( ORIENTATION = ROW, COMPRESSION = NO )
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NOCOMPRESS
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DISTRIBUTE BY HASH ("datatype1");
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ALTER TABLE "public"."runoob_alter_test" ALTER COLUMN "datatype2" SET DEFAULT '1';
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ALTER TABLE "public"."runoob_alter_test" ALTER COLUMN "datatype2" SET DEFAULT '3';
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ALTER TABLE "public"."runoob_alter_test" ALTER COLUMN "datatype2" DROP DEFAULT;
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ALTER TABLE "public"."runoob_alter_test" ALTER COLUMN "datatype2" DROP DEFAULT;</pre>
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</div>
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<div>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="dws_16_0119.html">Table (Optional Parameters and Operations)</a></div>
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</div>
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</div>
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