Updated on 2024-07-19 GMT+08:00

Deleting an Index

MySQL supports both DROP INDEX and ALTER TABLE DROP INDEX for deleting indexes. DSC will perform adaptation based on GaussDB(DWS) features during migration.

  1. DROP INDEX

    Input

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    CREATE TABLE `test_create_table03` (
    	`DEMAND_ID` INT(11) NOT NULL,
    	`DEMAND_NAME` CHAR(100) NOT NULL,
    	`THEME` VARCHAR(200) NULL DEFAULT NULL,
    	`SEND_ID` INT(11) NULL DEFAULT NULL,
    	`SEND_NAME` CHAR(20) NULL DEFAULT NULL,
    	`SEND_TIME` DATETIME NULL DEFAULT NULL,
    	`DEMAND_CONTENT` TEXT NOT NULL
    )
    COLLATE='utf8_general_ci'
    ENGINE=InnoDB;
    
    CREATE UNIQUE INDEX DEMAND_NAME_INDEX ON TEST_CREATE_TABLE03(DEMAND_NAME);
    DROP INDEX DEMAND_NAME_INDEX ON TEST_CREATE_TABLE03;
    
    CREATE INDEX SEND_ID_INDEX ON TEST_CREATE_TABLE03(SEND_ID);
    DROP INDEX SEND_ID_INDEX ON TEST_CREATE_TABLE03;
    

    Output

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    CREATE TABLE "public"."test_create_table03"
    (
      "demand_id" INTEGER NOT NULL,
      "demand_name" CHAR(400) NOT NULL,
      "theme" VARCHAR(800) DEFAULT NULL,
      "send_id" INTEGER DEFAULT NULL,
      "send_name" CHAR(80) DEFAULT NULL,
      "send_time" TIMESTAMP WITHOUT TIME ZONE DEFAULT NULL,
      "demand_content" TEXT NOT NULL
    )
      WITH ( ORIENTATION = ROW, COMPRESSION = NO )
      NOCOMPRESS
      DISTRIBUTE BY HASH ("demand_id");
    
    CREATE INDEX "demand_name_index" ON "public"."test_create_table03" ("demand_name");
    DROP INDEX "public"."demand_name_index" RESTRICT;
    
    CREATE INDEX "send_id_index" ON "public"."test_create_table03" USING BTREE ("send_id");
    DROP INDEX "public"."send_id_index" RESTRICT;
    
  2. ALTER TABLE DROP INDEX

    Input

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    CREATE TABLE `test_create_table03` (
    	`DEMAND_ID` INT(11) NOT NULL,
    	`DEMAND_NAME` CHAR(100) NOT NULL,
    	`THEME` VARCHAR(200) NULL DEFAULT NULL,
    	`SEND_ID` INT(11) NULL DEFAULT NULL,
    	`SEND_NAME` CHAR(20) NULL DEFAULT NULL,
    	`SEND_TIME` DATETIME NULL DEFAULT NULL,
    	`DEMAND_CONTENT` TEXT NOT NULL
    )
    COLLATE='utf8_general_ci'
    ENGINE=InnoDB;
    
    ALTER TABLE TEST_CREATE_TABLE03 ADD UNIQUE INDEX TEST_CREATE_TABLE03_NAME_INDEX(DEMAND_NAME(50));
    ALTER TABLE TEST_CREATE_TABLE03 DROP INDEX TEST_CREATE_TABLE03_NAME_INDEX;
    

    Output

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    CREATE TABLE "public"."test_create_table03"
    (
      "demand_id" INTEGER NOT NULL,
      "demand_name" CHAR(400) NOT NULL,
      "theme" VARCHAR(800) DEFAULT NULL,
      "send_id" INTEGER DEFAULT NULL,
      "send_name" CHAR(80) DEFAULT NULL,
      "send_time" TIMESTAMP WITHOUT TIME ZONE DEFAULT NULL,
      "demand_content" TEXT NOT NULL
    )
      WITH ( ORIENTATION = ROW, COMPRESSION = NO )
      NOCOMPRESS
      DISTRIBUTE BY HASH ("demand_id");
    
    CREATE INDEX "test_create_table03_name_index" ON "public"."test_create_table03" ("demand_name");
    DROP INDEX "public"."test_create_table03_name_index" RESTRICT;