ALTER TABLE table_name ADD CONSTRAINT MyPrimaryKey PRIMARY KEY (column1, column2...); DROP CONSTRAINT (删除约束),语法如下: ALTER TABLE table_name DROP CONSTRAINT MyUniqueConstraint; 如果是 MYSQL ,代码是这样: ALTER TABLE table_name DROP INDEX MyUniqueConstraint; DROP PRIMARY KEY (删除主键),语...
ALTER TABLE table_name DROP CONSTRAINT MyUniqueConstraint; 如果是 MYSQL ,代码是这样: ALTER TABLE table_name DROP INDEX MyUniqueConstraint; DROP PRIMARY KEY (删除主键),语法如下: ALTER TABLE table_name DROP CONSTRAINT MyPrimaryKey; 如果是 MYSQL ,代码是这样: ALTER TABLE table_name DROP PRIMARY KEY...
ALTERTABLEtable_nameADDCONSTRAINTMyPrimaryKeyPRIMARYKEY(column1, column2...); DROP CONSTRAINT (删除约束),语法如下: ALTERTABLEtable_nameDROPCONSTRAINTMyUniqueConstraint; 如果是 MYSQL ,代码是这样: ALTERTABLEtable_nameDROPINDEXMyUniqueConstraint; DROP PRIMARY KEY (删除主键),语法如下: ALTERTABLEtable_name...
ALTER TABLE table_name ADD CONSTRAINTMyPrimaryKeyPRIMARY KEY(column1,column2...); DROP CONSTRAINT (删除约束),语法如下: ALTER TABLE table_name DROP CONSTRAINTMyUniqueConstraint; 如果是 MYSQL ,代码是这样: ALTER TABLE table_name DROP INDEXMyUniqueConstraint; DROP PRIMARY KEY (删除主键),语法如下: A...
DROP INDEX MyUniqueConstraint; 1. 2. DROP PRIMARY KEY (删除主键),语法如下: ALTER TABLE table_name DROP CONSTRAINT MyPrimaryKey; 1. 2. 如果是 MYSQL ,代码是这样: ALTER TABLE table_name DROP PRIMARY KEY; 1. 2. 1.1.1 实例 创建COMPANY 表(下载 COMPANY SQL 文件),数据内容如下: ...
test=#altertabletbl_primaryaddconstraintpk_tbl_primary_a_bprimarykey(a,b);ALTERTABLE 方式二 将重复数据全部删除 第一步:删除主键约束,清空表,写入测试数据 altertabletbl_primarydropconstraintpk_tbl_primary_a_b ;ALTERTABLEtest=#deletefromtbl_primary;DELETE8test=#insertintotbl_primary (a,b)values(1...
ALTER TABLE table_name DROP CONSTRAINT MyUniqueConstraint; 如果是 MYSQL ,代码是这样: ALTER TABLE table_name DROP INDEX MyUniqueConstraint; DROP PRIMARY KEY (删除主键),语法如下: ALTER TABLE table_name DROP CONSTRAINT MyPrimaryKey; 如果是 MYSQL ,代码是这样: ...
i.indrelid = 'your_table_name'::regclass; your_table_name需要替换为你要操作的数据表名。 2、删除主键 确认主键信息后,可以使用以下SQL语句删除主键: ALTER TABLE your_table_name DROP CONSTRAINT your_primary_key_name; your_table_name为数据表名,your_primary_key_name为主键约束名。
= 'PRIMARY': # 如果不是主键外键,才删除外键并迁移数据到新表 cur.execute(f"ALTER TABLE {table} DROP CONSTRAINT {fk[0]};") data = data.join(data.loc[:, fk[1]:], on=fk[0], how='left') # 删除外键后,使用left join将数据迁移到新表 data = data.rename({fk[1]: f"{table}_new_...
foreign_keys = load(f"SELECT * FROM {table}_key;") # 删除外键并迁移数据到新表 for fk in foreign_keys: if fk[3] != 'PRIMARY': # 如果不是主键外键,才删除外键并迁移数据到新表 cur.execute(f"ALTER TABLE {table} DROP CONSTRAINT {fk[0]};") ...