1、已有表創建表外鍵:
alter table 表名 add constrain FK_約束名 foreign key([外鍵列]) references 主鍵表([主鍵列])
如:alter table cst_customer add constraint fk_industry_002 foreign key(cust_industry) references base_dict (dict_id);
2、已有表增加一列
alter table TABLE_NAME add column NEW_COLUMN_NAME varchar(45) not null;
如:alter table cst_customer add column cust_image varchar(50) not null;
3、修改表(加了_name的都是需要根據情況修改的)
修改表中字段長度:
alter table table_name modify field_name varchar(100);
如:alter table cst_customer modify cust_image varchar(100);
修改表中屬性名:
alter table table_name change old_name new_name type_name;
如:alter table tbl_emp change gender emp_gender char(1);
修改表中屬性類型:
alter table table_name modify column_name type_name;
如:alter table tbl_emp modify email varchar(200);
刪除表中某一列:
alter table table_name drop column_name;
如:alter table tbl_emp drop message;
給表中添加一列:
alter table table_name add column_name type_name;
如:alter table tbl_emp add message varchar(100);
修改表名:
alter table table_name rename new_name;
如:alter table tbl_amp rename tbl_emp;
4、向表中插入信息
insert into table_name values ( field1 ,field2 , field3 ,);
如:insert into cst_linkman values(1,"王二狗",3,"男","010-88888888","12121212121","[email protected]","888888888","leader","我就是我是顏色不一樣的煙火");
5、修改表中記錄的值
update table_name set field_name=new_value,…where(條件)
如:update cst_customer set lkm_gender=1 where lkm_id=1 or lkm_id=3;
6、修改表中非空字段爲空:
alter table table_name modify column column_name varchar(50) default null comment'名稱';
alter table cst_linkman modify column lkm_cust_id varchar(50) default null;
7、創建數據庫
create database table_name (default character set 字符集名)( default collate 校對規則名);
create database abc default character set utf8;