Oracle 表正在变异

在我插入这段代码后，我得到了一个错误

ORA-04091:表（架构）。员工正在变异，触发器/函数可能看不到它

ORA-06512：“HR.TRGADDEMP_1215034”，第7行

ORA-04088:执行触发器“HR.TRGADDEMP_1215034”时出错

我该怎么办

CREATE OR REPLACE TRIGGER TrgAddEmp_1215034
        AFTER INSERT ON Employees
        FOR EACH ROW

        DECLARE
        v_name varchar2(35);
        v_managerName varchar2(20);
        v_dept varchar2(35);

        BEGIN
        Select first_name||' '||last_name
        INTO v_name
        FROM Employees where employee_id = :new.employee_id;

        Select last_name 
        into v_managerName
        from employees where employee_id = :new.manager_id;

        Select department_name
        into v_dept
        from departments where department_id = :new.department_id;

        IF v_managerName is NULL THEN
        DBMS_OUTPUT.PUT_LINE('There is a new employee '|| v_name );
        DBMS_OUTPUT.PUT_LINE('The supervisor for this employee has not been decided');
        DBMS_OUTPUT.PUT_LINE('This employee is assigned to '||v_dept|| 'Department');
        ELSIF v_dept is NULL THEN
        DBMS_OUTPUT.PUT_LINE('There is a new employee '|| v_name );
        DBMS_OUTPUT.PUT_LINE('This employee is supervised by ' || v_managerName);
        DBMS_OUTPUT.PUT_LINE('The department for this employee has not been decided');
        ELSE
        DBMS_OUTPUT.PUT_LINE('There is a new employee '|| v_name );
        DBMS_OUTPUT.PUT_LINE('This employee is supervised by ' || v_managerName);
        DBMS_OUTPUT.PUT_LINE('This employee is assigned to '||v_dept|| 'Department');
        END IF;
        END;

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您应该插入正确的代码，而不是以下代码：）

ORA-4091

表示触发器试图从自己的表中选择数据。不要这样做。从不行级触发器不允许这样做

此代码尝试选择您已有的数据

---

当您有

：new.first\u name

和

：new.last\u name

时，为什么要尝试选择

first\u name

和

：new.last\u name

？等等…

将员工插入后的

替换为“员工插入前”

不要那么严格，有一个例外：你是对的。但这个例外意味着使用单行插入，所以任何应用程序修改都可能再次导致ORA-4091。这就是为什么我更喜欢说“从不”。