oracle - 如何复制多行 (Oracle)

Question

我正在尝试创建一个过程，该过程将复制表的多行(或仅一行)并为每一行插入递增 ID。

我的问题是，在我的程序中，我使用游标来选择要复制的行，当我选择该游标中没有 WHERE 条件的所有行时，一切正常。但是当我设置一个 WHERE 条件只选择一行时......没有任何反应

这是我的程序

CREATE OR REPLACE PROCEDURE DuplicateEmployee (p_EmployeeID IN Employee.id%TYPE)
 AS
  p_New_EmployeeID Employee.id%TYPE;
  CURSOR c_DuplicateEmployee IS
    SELECT *
        FROM Employee
        WHERE Employee.id = p_EmployeeID; -- if this line is deleted all content is duplicated
  row_Employee c_DuplicateEmployee%ROWTYPE;
    BEGIN
      FOR myEmployee IN c_DuplicateEmployee LOOP
          p_New_EmployeeID := employee_seq.NEXTVAL;
          INSERT INTO Employee(id, first_name, last_name, start_date, end_date, salary, city, description)
            VALUES(p_New_EmployeeID, myEmployee.first_name, myEmployee.last_name, myEmployee.start_date, myEmployee.end_date, myEmployee.salary, myEmployee.city, myEmployee.description);
      END LOOP;
    COMMIT;
   END DuplicateEmployee;

我知道在这个例子中有一个选择要复制的主键的过程是没有意义的，但在我的生产基地它将被用来选择一个外键。

下面是创建测试表和我用于此过程的 SEQUENCE 所需的代码

CREATE TABLE Employee
  (
    ID         VARCHAR2(4 BYTE) NOT NULL,
    First_Name VARCHAR2(10 BYTE),
    Last_Name  VARCHAR2(10 BYTE),
    Start_Date DATE,
    End_Date DATE,
    Salary      NUMBER(8,2),
    City        VARCHAR2(10 BYTE),
    Description VARCHAR2(15 BYTE)
  );
INSERT
INTO Employee
    (ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
  VALUES
    ('01', 'Jason', 'Martin', to_date('19960725','YYYYMMDD'), to_date('20060725','YYYYMMDD'), 1234.56, 'Toronto', 'Programmer');
INSERT
INTO Employee
    (ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
  VALUES
    ('02', 'Alison', 'Mathews', to_date('19760321','YYYYMMDD'), to_date('19860221','YYYYMMDD'), 6661.78, 'Vancouver', 'Tester');
INSERT
INTO Employee
    (ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
  VALUES
    ('03', 'James', 'Smith', to_date('19781212','YYYYMMDD'), to_date('19900315','YYYYMMDD'), 6544.78, 'Vancouver', 'Tester');
INSERT
INTO Employee
    (ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
  VALUES
    ('04', 'Celia', 'Rice', to_date('19821024','YYYYMMDD'), to_date('19990421','YYYYMMDD'), 2344.78, 'Vancouver', 'Manager');
INSERT
INTO Employee
    (ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
  VALUES
    ('05', 'Robert', 'Black', to_date('19840115','YYYYMMDD'), to_date('19980808','YYYYMMDD'), 2334.78, 'Vancouver', 'Tester');
 INSERT
INTO Employee
    (ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
  VALUES
    ('06', 'Linda', 'Green', to_date('19870730','YYYYMMDD'), to_date('19960104','YYYYMMDD'), 4322.78, 'New York', 'Tester');
INSERT
INTO Employee
    (ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
VALUES
    ('07', 'David', 'Larry', to_date('19901231','YYYYMMDD'), to_date('19980212','YYYYMMDD'), 7897.78, 'New York', 'Manager');
INSERT
INTO Employee
    (ID, First_Name, Last_Name, Start_Date, End_Date, Salary, City, Description)
VALUES
    ('08', 'James', 'Cat', to_date('19960917','YYYYMMDD'), to_date('20020415','YYYYMMDD'), 1232.78, 'Vancouver', 'Tester');

此处为将管理主键 (ID) 的序列

CREATE SEQUENCE "TEST"."EMPLOYEE_SEQ" MINVALUE 1 MAXVALUE 999999999999999999999999999 INCREMENT BY 1 START WITH 1 NOCACHE ORDER NOCYCLE ;

这里是执行程序的代码

BEGIN
  employeepackage.duplicateemployee(5);
END;

我真的不明白为什么它在复制所有行时不能对单行正常工作？少于 2 行的游标有限制吗？

任何帮助将不胜感激;)

Answer 1

为什么需要游标？您可以直接使用 SQL 执行此操作:

INSERT INTO Employee(id, first_name, last_name, 
                     start_date, end_date, 
                     salary, city, description)
SELECT employee_seq.NEXTVAL, e.first_name, e.last_name,
       e.start_date, e.end_date, 
       e.salary, e.city, e.description
FROM Employee e
WHERE e.id = p_EmployeeID;

无论如何，实际问题是您的 ID 是 VARCHAR2(4)，而您认为它是 NUMBER。您实际上没有 ID = 5 的员工，但您确实有 ID = '05' 的员工。因此，无需更改任何内容，您的程序就可以运行:

BEGIN
  employeepackage.duplicateemployee('05');
END;

当然，改变ID的数据类型是有意义的。