數據庫表常用操作

ORACLE

--修改表結構
ALTER TABLE table_name  RENAME TO table_name2	--修改表名
ALTER TABLE table_name  RENAME COLUMN column_name TO column_name2 --修改表列名
ALTER TABLE table_name  MODIFY column_name NUMBER(20) --修改字段類型
ALTER TABLE table_name  MODIFY ("column_name" NOT NULL ENABLE);	--修改字段類型
ALTER TABLE table_name  ADD column_name VARCHAR2(40) --添加表列
ALTER TABLE table_name  DROP column_name CASCADECONSTRAINTS --刪除表列

--添加comment
COMMENT ON COLUMN "table_name"."column_name" IS 'hello';

--oracle沒有boolean類型所以用NUMBER(1,0)代替
"WARNING" NUMBER(1,0) DEFAULT 0

--新建sequence
CREATE SEQUENCE  "sequence_name"  MINVALUE 0 MAXVALUE 9999999 INCREMENT BY 1 START WITH 60 CACHE 20 ORDER  NOCYCLE ;

--新建表約束
CREATE UNIQUE INDEX "unique_name" ON "table_name" ("column_name")
ALTER TABLE "table_name" ADD CONSTRAINT "unique_name" UNIQUE ("column_name")
--主鍵
ALTER TABLE "table_name" ADD CONSTRAINT "primarykey_name" PRIMARY KEY ("column_name")
--聯合主鍵
ALTER TABLE "table_name" ADD CONSTRAINT "primarykey_name" PRIMARY KEY ("column_name", "column_name2")
--外鍵
ALTER TABLE "table_name" ADD CONSTRAINT "foreignkey_name" FOREIGN KEY ("column_name")
	  REFERENCES "table_name2" ("column_name2") ENABLE;