10.PL_SQL――PL_SQL中的复合数据类型之RECORDS
一、记录和集合概述
目前为止所介绍的变量的数据类型都属于scalar，即标量，如整形，字符串，日期等等。任何一种编程语言都需要提供一些手段让用户创建更复杂的变量，PL/SQL也不例外，本章就来介绍一下PL/SQL中的复合型变量。
PL/SQL的复合型变量主要包括两类：
1. Records：记录
2. Collection：集合。Collection又可以分为三种，
a. Associative Array（INDEXTBY table）: 关联数组（或称索引表，和SQL中的INDEX OF TABLE不是一个概念）
b. Nested Table: 嵌套表
c. Varray: 可变长度列表。
二、记录和集合的区别
Records可以形象的理解为一个容器，用来保存很多其他的数据类型，但每种数据类型只在记录中出现一次，例如一个记录中保存了如下数据类型：
PL/SQL Record：
这个记录中保存了布尔型、日期型、字符型和BLOB型变量，且每个变量都只出现了一次，每个存放其他数据类型的空间称为域（Field）
SQL> edit
DECLARE
TYPE myrecord IS RECORD
(id number(8),
name varchar2(20)default 'Wilson',
birthday DATE
);
person myrecord;
BEGIN
person.id :=12345;
person.birthday :=SYSDATE;
DBMS_OUTPUT.PUT_LINE('Name: '|| person.name);
END;
/
SQL> /
Name: Wilson
===============================
SQL> edit
DECLARE
person employees%ROWTYPE；
BEGIN
SELECT * INTO person
FROM employees WHEREemployee_id = 100;
DBMS_OUTPUT.PUT_LINE('Name: '|| person.first_name);
END;
/
SQL> @notes/s37.sql
Name: Steven
PL/SQL procedure successfully completed.
===============================================
eg3.
SQL> edit
DECLARE
TYPE t_rec IS RECORD
(v_sal number(8),
v_minsal number(8)default 1000,
v_hire_dateemployees.hire_date%TYPE,
v_reclemployees%ROWTYPE);
v_myrec t_rec;
BEGIN
v_myrec.v_sal := v_myrec.v_minsal+ 500;
v_myrec.v_hire_date :=SYSDATE;
SELECT * INTO v_myrec.v_recl
FROM employees WHEREemployee_id = 100;
DBMS_OUTPUT.PUT_LINE(v_myrec.v_recl.last_name || ' ' || TO_CHAR(v_myrec.v_hire_date) || ' '|| TO_CHAR(v_myrec.v_sal));
END;
/
SQL> @notes/s38.sql
King 24-AUG-14 1500
PL/SQL procedure successfully completed.
CREATE TABLE retired_emps (
EMPNO NUMBER(4),
ENAME VARCHAR2(25),
JOB VARCHAR2(9),
MGR NUMBER(4),
HIREDATE DATE,
LEAVEDATE DATE,
SAL NUMBER(7,2),
COMM NUMBER(7,2),
DEPTNO NUMBER(2)
);
SQL> @notes/s39.sql
Table created.
SQL> select * from retired_emps where empno = 124;
no rows selected
SQL> edit
DECLARE
v_employee_number NUMBER :=124;
v_emp_rec employees%ROWTYPE;
BEGIN
SELECT * INTO v_emp_rec FROMemployees
WHERE employee_id =v_employee_number;
INSERT INTOretired_emps(empno, ename, job, mgr,
hiredate,leavedate, sal, comm, deptno)
VALUES( v_emp_rec.employee_id,v_emp_rec.last_name,
v_emp_rec.job_id,v_emp_rec.manager_id,
v_emp_rec.hire_date,SYSDATE,
v_emp_rec.salary,v_emp_rec.commission_pct,
v_emp_rec.department_id);
COMMIT;
END;
/
SQL> @notes/s40.sql
PL/SQL procedure successfully completed.
SQL> select * from retired_emps where empno = 124;
EMPNO ENAME JOB MGR HIREDATE LEAVEDATE SAL COMM DEPTNO
---------- ---------- --------------- --------- ------------------- --------- ---------- ---------- ----------
124 Mourgos ST_MAN 100 16-NOV-07 24-AUG-14 5800 50
=========================INSERT============================
SQL> edit
DECLARE
v_employee_number NUMBER := 127;
v_emp_rec retired_emps%ROWTYPE;
BEGIN
SELECT employee_id, last_name, job_id,manager_id,
hire_date, hire_date, salary,commission_pct,
department_id INTO v_emp_rec
FROM employees
WHERE employee_id = v_employee_number;
INSERT INTO retired_emps
VALUES v_emp_rec;
-- 将查询结果打包到v_emp_rec中
END;
/
SELECT * FROMretired_emps;
SQL>@notes/s41.sql
PL/SQL proceduresuccessfully completed.
EMPNO ENAME JOB MGR HIREDATE LEAVEDATE SAL COMM DEPTNO
----------------------------------- --------- ---------- --------- --------- -------------------- ----------
124 Mourgos ST_MAN 100 16-NOV-07 24-AUG-14 5800 50
127 Landry ST_CLERK 120 14-JAN-07 14-JAN-07 3200 50
=========================UPDATE============================
SQL> edit
SET VERIFY OFF
DECLARE
v_employee_number NUMBER:= 127;
v_emp_recretired_emps%ROWTYPE;
BEGIN
SELECT *
INTO v_emp_rec
FROM retired_emps
WHERE empno =v_employee_number;
v_emp_rec.leavedate :=CURRENT_DATE;
UPDATE retired_emps SETROW = v_emp_rec
WHERE empno = v_employee_number;
END;
/
SELECT * FROM retired_emps;
SQL> @notes/s42.sql
PL/SQL procedure successfully completed.
EMPNO ENAME JOB MGR HIREDATE LEAVEDATE SAL COMM DEPTNO
---------- -------------- ---------- --------- ---------- ------------------ ---------- ---------- ----------
124 Mourgos ST_MAN 100 16-NOV-07 24-AUG-14 5800 50
127 Landry ST_CLERK 120 14-JAN-07 24-AUG-14 3200 50
SQL> edit
DECLARE
myrec employees%ROWTYPE;
BEGIN
myrec := NULL;
END;
/
SQL> @notes/s43.sql
PL/SQL procedure successfully completed.