WebFeb 22, 2010 · alter table my_table drop constraint my_pk; alter table my_table add constraint my_pk primary key (city_id, buildtime, time); However, if there are other tables with foreign keys that reference this primary key, then you will need to drop those first, do the above, and then re-create the foreign keys with the new column list. WebADD PRIMARY KEY (ID); To allow naming of a PRIMARY KEY constraint, and for defining a PRIMARY KEY constraint on multiple columns, use the following SQL syntax: ALTER …
sql - Change Primary Key - Stack Overflow
WebUNIQUE追加の基本構文 ALTER TABLE テーブル名 ADD CONSTRAINT 制約名 UNIQUE (カラム名); ※「CONSTRAINT 制約名」は省略可。 省略した場合はカラム名が制約名となる。 一意制約 (UNIQUE)の作成例 以下は「ALTER TABLE」を使い「sample」テーブルの「name」に一意制約 (UNIQUE)を追加する例です。 一意制約(UNIQUE)作成前 > SHOW CREATE … WebMar 5, 2024 · filter_none. To set the column age as the new primary key: ALTER TABLE info DROP PRIMARY KEY, ADD PRIMARY KEY (age); filter_none. Here we first drop the current primary key and then in the latter half of the statement we newly set the primary key on the age column. To check the primary key is now updated: rick stacy morning show jill
MySQL プライマリーキーを作成する(ALTER TABLE文)
WebNote: If you use ALTER TABLE to add a primary key, the primary key column(s) must have been declared to not contain NULL values (when the table was first created). DROP a … WebPRIMARY KEY on ALTER TABLE To create a PRIMARY KEY constraint on the "ID" column when the table is already created, use the following SQL: ALTER TABLE Persons ADD PRIMARY KEY (ID); To allow naming of a PRIMARY KEY constraint, and for defining a PRIMARY KEY constraint on multiple columns, use the following SQL syntax: ALTER … http://mysql.phi-integration.com/sql/cara-menambahkan-primary-key-pada-mysql rick stacy morning show podcast