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更新时间：2024-04-18 GMT+08:00
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唯一索引

GaussDB(DWS) 不支持唯一索引(约束)与主键约束联合使用。DSC工具迁移时会根据GaussDB(DWS)的特性进行相应适配。

MySQL唯一索引(约束)与主键约束联合使用的场景在工具迁移时会与OLAP场景下的分布键构成复杂的关系。工具暂不支持唯一索引(约束)与主键约束联合使用的场景。

  1. 内联唯一索引，如存在主键索引与唯一索引是相同列，DSC工具迁移时会将唯一索引移除。

    输入示例

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    CREATE TABLE IF NOT EXISTS `public`.`runoob_dataType_test`
(
  `id` INT PRIMARY KEY AUTO_INCREMENT,
  `name` VARCHAR(128) NOT NULL,
  UNIQUE (id ASC)
);

    输出示例

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    CREATE TABLE IF NOT EXISTS "public"."runoob_datatype_test"
(
  "id" SERIAL PRIMARY KEY,
  "name" VARCHAR(128) NOT NULL
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("id");
  2. ALTER TABLE创建唯一索引，DSC工具迁移时会根据GaussDB(DWS)的特性创建普通索引。

    输入示例

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    CREATE TABLE IF NOT EXISTS `public`.`runoob_alter_test`(
    `dataType1` int,
    `dataType2` FLOAT(10,2),
    `dataType3` DOUBLE(20,8)
)ENGINE=InnoDB DEFAULT CHARSET=utf8;

ALTER TABLE runoob_alter_test ADD UNIQUE idx_runoob_alter_test_datatype1(dataType1);
ALTER TABLE runoob_alter_test ADD UNIQUE INDEX idx_runoob_alter_test_datatype1(dataType2);
ALTER TABLE runoob_alter_test ADD UNIQUE KEY idx_runoob_alter_test_datatype1(dataType3);

CREATE TABLE IF NOT EXISTS `public`.`runoob_alter_test`(
    `dataType1` int,
    `dataType2` FLOAT(10,2),
    `dataType3` DOUBLE(20,8),
    `dataType4` TEXT NOT NULL,
    `dataType5` YEAR NOT NULL DEFAULT '2018',
    `dataType6` DATETIME NOT NULL DEFAULT '2018-10-12 15:27:33.999999'
)ENGINE=InnoDB DEFAULT CHARSET=utf8;

ALTER TABLE runoob_alter_test ADD CONSTRAINT UNIQUE idx_runoob_alter_test_datatype1(dataType1);
ALTER TABLE runoob_alter_test ADD CONSTRAINT UNIQUE INDEX idx_runoob_alter_test_datatype2(dataType2);
ALTER TABLE runoob_alter_test ADD CONSTRAINT UNIQUE KEY idx_runoob_alter_test_datatype3(dataType3);
ALTER TABLE runoob_alter_test ADD CONSTRAINT constraint_dataType UNIQUE idx_runoob_alter_test_datatype4(dataType4);
ALTER TABLE runoob_alter_test ADD CONSTRAINT constraint_dataType UNIQUE INDEX idx_runoob_alter_test_datatype5(dataType5);
ALTER TABLE runoob_alter_test ADD CONSTRAINT constraint_dataType UNIQUE KEY idx_runoob_alter_test_datatype6(dataType6);

    输出示例

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    CREATE TABLE IF NOT EXISTS "public"."runoob_alter_test"
(
  "datatype1" INTEGER,
  "datatype2" REAL,
  "datatype3" DOUBLE PRECISION
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("datatype1");

CREATE INDEX "idx_runoob_alter_test_datatype1" ON "public"."runoob_alter_test" ("datatype1");
CREATE INDEX "idx_runoob_alter_test_datatype1" ON "public"."runoob_alter_test" ("datatype2");
CREATE INDEX "idx_runoob_alter_test_datatype1" ON "public"."runoob_alter_test" ("datatype3");

CREATE TABLE IF NOT EXISTS "public"."runoob_alter_test"
(
  "datatype1" INTEGER,
  "datatype2" REAL,
  "datatype3" DOUBLE PRECISION,
  "datatype4" TEXT NOT NULL,
  "datatype5" SMALLINT NOT NULL DEFAULT '2018',
  "datatype6" TIMESTAMP WITHOUT TIME ZONE NOT NULL DEFAULT '2018-10-12 15:27:33.999999'
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("datatype1");

CREATE INDEX "idx_runoob_alter_test_datatype1" ON "public"."runoob_alter_test" ("datatype1");
CREATE INDEX "idx_runoob_alter_test_datatype2" ON "public"."runoob_alter_test" ("datatype2");
CREATE INDEX "idx_runoob_alter_test_datatype3" ON "public"."runoob_alter_test" ("datatype3");
CREATE INDEX "idx_runoob_alter_test_datatype4" ON "public"."runoob_alter_test" ("datatype4");
CREATE INDEX "idx_runoob_alter_test_datatype5" ON "public"."runoob_alter_test" ("datatype5");
CREATE INDEX "idx_runoob_alter_test_datatype6" ON "public"."runoob_alter_test" ("datatype6");
  3. CREATE INDEX创建唯一索引，DSC工具迁移时会根据GaussDB(DWS)的特性创建普通索引。

    输入示例

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    CREATE TABLE `public`.`test_index_table01` (
	`TABLE01_ID` INT(11) NOT NULL,
	`TABLE01_THEME` VARCHAR(100) NULL DEFAULT NULL,
	`AUTHOR_NAME` CHAR(10) NULL DEFAULT NULL,
	`AUTHOR_ID` INT(11) NULL DEFAULT NULL,
	`CREATE_TIME` INT NULL DEFAULT NULL,
	PRIMARY KEY(`TABLE01_ID`)
);
CREATE UNIQUE INDEX AUTHOR_INDEX ON `test_index_table01`(AUTHOR_ID);

    输出示例

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    CREATE TABLE "public"."test_index_table01"
(
  "table01_id" INTEGER NOT NULL,
  "table01_theme" VARCHAR(400) DEFAULT NULL,
  "author_name" CHAR(40) DEFAULT NULL,
  "author_id" INTEGER DEFAULT NULL,
  "create_time" INTEGER DEFAULT NULL,
  PRIMARY KEY ("table01_id")
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("table01_id");
CREATE INDEX "author_index" ON "public"."test_index_table01" ("author_id");
  4. CREATE TABLE中存在多个唯一索引，DSC工具迁移时会根据GaussDB(DWS)的特性将所有唯一索引创建为普通索引。

    输入示例

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    CREATE TABLE `public`.`test_index_table01` (
	`TABLE01_ID` INT(11) NOT NULL,
	`TABLE01_THEME` VARCHAR(100) NULL DEFAULT NULL,
	`AUTHOR_NAME` CHAR(10) NULL DEFAULT NULL,
	`AUTHOR_ID` INT(11) NULL DEFAULT NULL,
	`CREATE_TIME` INT NULL DEFAULT NULL,
	UNIQUE(`TABLE01_ID`),
	UNIQUE(`AUTHOR_ID`)
);

    输出示例

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    CREATE TABLE "public"."test_index_table01" (
  "table01_id" INTEGER NOT NULL,
  "table01_theme" VARCHAR(400) DEFAULT NULL,
  "author_name" CHAR(40) DEFAULT NULL,
  "author_id" INTEGER DEFAULT NULL,
  "create_time" INTEGER DEFAULT NULL
) WITH (ORIENTATION = ROW, COMPRESSION = NO) NOCOMPRESS DISTRIBUTE BY HASH ("table01_id");
CREATE INDEX "idx_test_index_table01_table01_id" ON "public"."test_index_table01"("TABLE01_ID");
CREATE INDEX "idx_test_index_table01_author_id" ON "public"."test_index_table01"("AUTHOR_ID");
  5. CREATE TABLE中存在一个唯一索引，并不存在主键索引时，DSC工具迁移时会根据GaussDB(DWS)的特性保留该唯一索引。

    输入示例

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    CREATE TABLE `public`.`test_index_table01` (
	`TABLE01_ID` INT(11) NOT NULL,
	`TABLE01_THEME` VARCHAR(100) NULL DEFAULT NULL,
	`AUTHOR_NAME` CHAR(10) NULL DEFAULT NULL,
	`AUTHOR_ID` INT(11) NULL DEFAULT NULL,
	`CREATE_TIME` INT NULL DEFAULT NULL,
	UNIQUE(`AUTHOR_ID`)
);

    输出示例

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    CREATE TABLE "public"."test_index_table01" (
  "table01_id" INTEGER NOT NULL,
  "table01_theme" VARCHAR(400) DEFAULT NULL,
  "author_name" CHAR(40) DEFAULT NULL,
  "author_id" INTEGER DEFAULT NULL,
  "create_time" INTEGER DEFAULT NULL,
  UNIQUE ("author_id")
) WITH (ORIENTATION = ROW, COMPRESSION = NO) NOCOMPRESS DISTRIBUTE BY HASH ("author_id");

  6. CREATE TABLE中存在主键索引时，DSC工具迁移时会根据GaussDB(DWS)的特性将所有的唯一索引创建为普通索引。

    输入示例

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    CREATE TABLE `public`.`test_index_table01` (
	`TABLE01_ID` INT(11) NOT NULL,
	`TABLE01_THEME` VARCHAR(100) NULL DEFAULT NULL,
	`AUTHOR_NAME` CHAR(10) NULL DEFAULT NULL,
	`AUTHOR_ID` INT(11) NULL DEFAULT NULL,
	`CREATE_TIME` INT NULL DEFAULT NULL,
	PRIMARY KEY(`TABLE01_ID`),
	UNIQUE(`AUTHOR_ID`)
);

    输出示例

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    CREATE TABLE "public"."test_index_table01" (
  "table01_id" INTEGER NOT NULL,
  "table01_theme" VARCHAR(400) DEFAULT NULL,
  "author_name" CHAR(40) DEFAULT NULL,
  "author_id" INTEGER DEFAULT NULL,
  "create_time" INTEGER DEFAULT NULL,
  PRIMARY KEY ("table01_id")
) WITH (ORIENTATION = ROW, COMPRESSION = NO) NOCOMPRESS DISTRIBUTE BY HASH ("table01_id");
CREATE INDEX "idx_test_index_table01_author_id" ON "public"."test_index_table01"("AUTHOR_ID");
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