我试图删除我创建的employee表,但由于外键的约束而无法删除。当我删除employee时,我得到了这个错误(Cannot drop table 'employee' referenced by a foreign key constraint 'branch_ibfk_1' on table 'branch')
CREATE TABLE employee (
emp_id INT PRIMARY KEY,
first_name VARCHAR(40),
last_name VARCHAR(40),
birth_day DATE,
sex VARCHAR(1),
salary INT,
super_id INT,
branch_id INT
);
ALTER TABLE employee
ADD FOREIGN KEY(branch_id)
REFERENCES branch(branch_id)
ON DELETE SET NULL;
ALTER TABLE employee
ADD FOREIGN KEY(super_id)
REFERENCES employee(emp_id)
ON DELETE SET NULL;
CREATE TABLE branch (
branch_id INT PRIMARY KEY,
branch_name VARCHAR(40),
mgr_id INT,
mgr_start_date DATE,
FOREIGN KEY(mgr_id) REFERENCES employee(emp_id) ON DELETE SET NULL
);
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2条答案
按热度按时间cigdeys31#
这样做:
删除表分支;
下拉表员工;
8wigbo562#
试试这个:
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