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>
2.8 KiB
2.8 KiB
MODIFY (Modifying a Cloumn)
MySQL uses the MODIFY keyword to change column data types and set NOT NULL constraints. DSC will perform adaptation based on GaussDB(DWS) features during migration.
Input
CREATE TABLE IF NOT EXISTS `runoob_alter_test`(
`dataType0` varchar(100),
`dataType1` bigint,
`dataType2` bigint,
`dataType3` bigint
)ENGINE=InnoDB DEFAULT CHARSET=utf8;
## A.
ALTER TABLE runoob_alter_test MODIFY dataType1 smallint;
## B.
ALTER TABLE runoob_alter_test MODIFY dataType1 smallint NOT NULL;
## C.
ALTER TABLE runoob_alter_test MODIFY dataType1 smallint NOT NULL FIRST;
## D.
ALTER TABLE runoob_alter_test MODIFY dataType1 smallint NOT NULL AFTER dataType3;
Output
CREATE TABLE "public"."runoob_alter_test"
(
"datatype0" VARCHAR(400),
"datatype1" BIGINT,
"datatype2" BIGINT,
"datatype3" BIGINT
)
WITH ( ORIENTATION = ROW, COMPRESSION = NO )
NOCOMPRESS
DISTRIBUTE BY HASH ("datatype0");
-- A.
ALTER TABLE "public"."runoob_alter_test" MODIFY "datatype1" SMALLINT NULL DEFAULT NULL;
-- B.
ALTER TABLE "public"."runoob_alter_test" MODIFY "datatype1" SMALLINT NOT NULL;
-- C.
ALTER TABLE "public"."runoob_alter_test" MODIFY "datatype1" SMALLINT NOT NULL;
-- D.
ALTER TABLE "public"."runoob_alter_test" MODIFY "datatype1" SMALLINT NOT NULL;
Parent topic: Table (Optional Parameters and Operations)