1. PL / SQL创建对象
CREATE OR REPLACE TYPE typ_address AS OBJECT (
street VARCHAR2(30),
city VARCHAR2(20),
state CHAR(2),
postal_code VARCHAR2(6)
);
CREATE OR REPLACE TYPE typ_employee AS OBJECT(
employee_id NUMBER(6),
first_name VARCHAR2(20),
last_name VARCHAR2(25),
email VARCHAR2(25),
phone_number VARCHAR2(25),
hire_date DATE,
job_id VARCHAR2(25),
salary NUMBER(8,2),
commission_pct NUMBER(2,2),
manager_id NUMBER(6),
department_id NUMBER(4),
address typ_address
MAP MEMBER FUNCTION get_idno RETURN NUMBER,
MEMBER PROCEDURE display_address(SELF IN OUT NOCOPY typ_employee)
);
--创建对象体
CREATE TYPE BODY typ_employee AS
MAP MEMBER FUNCTION get_idno RETURN NUMBER IS
BEGIN
RETURN employee_id;
END;
MEMBER PROCEDURE display_address ( SELF IN OUT NOCOPY typ_employee ) IS
BEGIN
DBMS_OUTPUT.PUT_LINE(first_name || ‘ ‘ || last_name);
DBMS_OUTPUT.PUT_LINE(address.street);
DBMS_OUTPUT.PUT_LINE(address.city || ‘, ‘ || address.state || ‘ ‘ ||
address.postal_code);
END;
END;
--持久化对象
CREATE TABLE employee_tab OF typ_employee;
CREATE TYPE emp_typ as table of typ_employee;
3. 在PL/SQL块中声明对象：
DECLARE
emp typ_employee; -- emp is atomically null
BEGIN
-- call the constructor for typ_employee
emp := typ_employee(315, ‘Francis‘, ‘Logan‘, ‘FLOGAN‘,
‘555.777.2222‘, to_date(‘2012-12-24‘, ‘yyyy-mm-dd‘), ‘SA_MAN‘, 11000, .15, 101, 110,
typ_address(‘376 Mission‘, ‘San Francisco‘, ‘CA‘, ‘94222‘));
--DBMS_OUTPUT.PUT_LINE(emp.first_name || ‘ ‘ || emp.last_name); -- display details
emp.display_address(); -- call object method to display details
END;
4. PL/SQL如何处理未初始化的对象：
--对象初始化之后才能被赋值
DECLARE
emp typ_employee; -- emp is atomically null
BEGIN
IF emp IS NULL THEN DBMS_OUTPUT.PUT_LINE(‘emp is NULL #1‘); END IF;
IF emp.employee_id IS NULL THEN
DBMS_OUTPUT.PUT_LINE(‘emp.employee_id is NULL #1‘);
END IF;
emp := typ_employee(NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL, NULL,
typ_address(NULL, NULL, NULL, NULL));
-- emp := NULL; -- this would have made the following IF statement TRUE
IF emp IS NULL THEN DBMS_OUTPUT.PUT_LINE(‘emp is NULL #3‘); END IF;
IF emp.employee_id IS NULL THEN
DBMS_OUTPUT.PUT_LINE(‘emp.employee_id is NULL #3‘);
END IF;
emp.employee_id := 330;
IF emp IS NULL THEN DBMS_OUTPUT.PUT_LINE(‘emp is NULL #2‘); END IF;
IF emp.employee_id IS NULL THEN
DBMS_OUTPUT.PUT_LINE(‘emp.employee_id is NULL #2‘);
END IF;
EXCEPTION
WHEN ACCESS_INTO_NULL THEN
DBMS_OUTPUT.PUT_LINE(‘Cannot assign value to NULL object‘);
END;
5. 在PL/SQL中操纵对象：
5.1.调用对象构造器和方法（Calling Object Constructors and Methods）
--构造器传入参数
DECLARE
emp typ_employee;
BEGIN
INSERT INTO employee_tab VALUES (typ_employee(310, ‘Evers‘, ‘Boston‘, ‘EBOSTON‘,
‘555.111.2222‘, to_date(‘2012-12-24‘, ‘yyyy-mm-dd‘), ‘SA_REP‘, 9000, .15, 101, 110,
typ_address(‘123 Main‘, ‘San Francisco‘, ‘CA‘, ‘94111‘)) );
INSERT INTO employee_tab VALUES (typ_employee(320, ‘Martha‘, ‘Dunn‘, ‘MDUNN‘,
‘555.111.3333‘, to_date(‘2012-11-5‘, ‘yyyy-mm-dd‘), ‘AC_MGR‘, 12500, 0, 101, 110,
typ_address(‘123 Broadway‘, ‘Redwood City‘, ‘CA‘, ‘94065‘)) );
INSERT INTO employee_tab VALUES (typ_employee(370, ‘Robert‘, ‘Myers‘, ‘RMYERS‘,
‘555.111.2277‘, to_date(‘2012-3-7‘, ‘yyyy-mm-dd‘), ‘SA_REP‘, 8800, .12, 101, 110,
typ_address(‘540 Fillmore‘, ‘San Francisco‘, ‘CA‘, ‘94011‘)) );
END;
5.2 更新和删除对象：
--删除对应的对象表
DECLARE
emp typ_employee;
BEGIN
UPDATE employee_tab e SET e.address.street = ‘1040 California‘
WHERE e.employee_id = 370;
DELETE FROM employee_tab e WHERE e.employee_id = 310;
END;
SELECT REF(e) FROM employee_tab e WHERE e.employee_id = 370;
6. 通过REF修饰符操纵对象：
DECLARE
emp typ_employee;
emp_ref REF typ_employee;
emp_name VARCHAR2(50);
BEGIN
SELECT REF(e) INTO emp_ref FROM employee_tab e WHERE e.employee_id = 370;
-- the following assignment raises an error, not allowed in PL/SQL
-- emp_name := emp_ref.first_name || ‘ ‘ || emp_ref.last_name;
-- emp := DEREF(emp_ref); not allowed, cannot use DEREF in procedural statements
SELECT DEREF(emp_ref) INTO emp FROM DUAL; -- use dummy table DUAL
emp.display_address();
END;
7. 定义相当于PL/SQL集合类型的SQL类型（Defining SQL Types Equivalent to PL/SQL Collection Types）
7.1 定义嵌套表：
--建嵌套表类型
CREATE TYPE CourseList AS TABLE OF VARCHAR2(10) -- define type
--建对象类型
CREATE TYPE student AS OBJECT ( -- create object
id_num INTEGER(4),
name VARCHAR2(25),
address VARCHAR2(35),
status CHAR(2),
courses CourseList); -- declare nested table as attribute
--建立嵌套表类型表
CREATE TABLE sophomores of student
NESTED TABLE courses STORE AS courses_nt;
--插入数据
insert into sophomores
values(1,‘dylan‘,‘CARL STREET‘,‘ACTIVE‘,
CourseList(‘MATH1020‘)
);
--查询
SELECT a.*, b.*
from sophomores a, TABLE(a.courses) b;
select /*+ nested_table_get_refs */ *
from courses_nt t;
7.2 定义数组：
-- 声明数组类型（Each project has a 16-character code name）
-- We will store up to 50 projects at a time in a database column.
CREATE TYPE ProjectList AS VARRAY(50) OF VARCHAR2(16);
--创建表
CREATE TABLE dept_projects ( -- create database table
dept_id NUMBER(2),
name VARCHAR2(15),
budget NUMBER(11,2),
-- Each department can have up to 50 projects.
projects ProjectList);
--插入数据：
INSERT INTO dept_projects
VALUES(60, ‘Security‘, 750400,
ProjectList(‘New Badges‘, ‘Track Computers‘, ‘Check Exits‘));
8. 在动态SQL中使用对象：
8.1 定义对象类型person_typ和数组类型hobbies_var,并创建报TEAMS:
CREATE TYPE person_typ AS OBJECT (name VARCHAR2(25), age NUMBER);
CREATE TYPE hobbies_var AS VARRAY(10) OF VARCHAR2(25);
CREATE OR REPLACE PACKAGE teams
AUTHID CURRENT_USER AS
PROCEDURE create_table (tab_name VARCHAR2);
PROCEDURE insert_row (tab_name VARCHAR2, p person_typ, h hobbies_var);
PROCEDURE print_table (tab_name VARCHAR2);
END;
CREATE OR REPLACE PACKAGE BODY teams AS
PROCEDURE create_table (tab_name VARCHAR2) IS
BEGIN
EXECUTE IMMEDIATE ‘CREATE TABLE ‘ || tab_name ||
‘ (pers person_typ, hobbs hobbies_var)‘;
END;
PROCEDURE insert_row (
tab_name VARCHAR2,
p person_typ,
h hobbies_var) IS
BEGIN
EXECUTE IMMEDIATE ‘INSERT INTO ‘ || tab_name ||
‘ VALUES (:1, :2)‘ USING p, h;
END;
PROCEDURE print_table (tab_name VARCHAR2) IS
TYPE refcurtyp IS REF CURSOR;
v_cur refcurtyp;
p person_typ;
h hobbies_var;
BEGIN
OPEN v_cur FOR ‘SELECT pers, hobbs FROM ‘ || tab_name;
LOOP
FETCH v_cur INTO p, h;
EXIT WHEN v_cur%NOTFOUND;
-- print attributes of ‘p‘ and elements of ‘h‘
DBMS_OUTPUT.PUT_LINE(‘Name: ‘ || p.name || ‘ - Age: ‘ || p.age);
FOR i IN h.FIRST..h.LAST
LOOP
DBMS_OUTPUT.PUT_LINE(‘Hobby(‘ || i || ‘): ‘ || h(i));
END LOOP;
END LOOP;
CLOSE v_cur;
END;
END;
8.2 调用TEAMS包中的存储过程：
DECLARE
team_name VARCHAR2(15);
BEGIN
team_name := ‘Notables‘;
TEAMS.create_table(team_name);
TEAMS.insert_row(team_name, person_typ(‘John‘, 31),
hobbies_var(‘skiing‘, ‘coin collecting‘, ‘tennis‘));
TEAMS.insert_row(team_name, person_typ(‘Mary‘, 28),
hobbies_var(‘golf‘, ‘quilting‘, ‘rock climbing‘, ‘fencing‘));
TEAMS.print_table(team_name);
END;
=================================================
output:
Name: John - Age: 31
Hobby(1): skiing
Hobby(2): coin collecting
Hobby(3): tennis
Name: Mary - Age: 28
Hobby(1): golf
Hobby(2): quilting
Hobby(3): rock climbing
Hobby(4): fencing
PL/SQL 过程已成功完成。