--[4]
------------------------------------------------------------------------------------- --显示游标--------------------------------------------------------- --001 DECLARE CURSOR c1 IS --声明游标 SELECT name,address FROM student ORDER BY name; v_name student.name%TYPE; v_addr student.address%TYPE; BEGIN OPEN c1; --打开游标 FETCH c1 INTO v_name,v_addr; --第一次定位读取数据,并保存在变量 --循环读取数据 WHILE c1%FOUND LOOP DBMS_OUTPUT.PUT_LINE(TO_CHAR(c1%ROWCOUNT) || ' ' || v_name || ' , ' || v_addr); FETCH c1 INTO v_name,v_addr; END LOOP; DBMS_OUTPUT.PUT_LINE('Total rows is : ' || c1%ROWCOUNT); CLOSE c1; --关闭游标 END; / --002 DECLARE CURSOR cur_emp IS SELECT sal FROM emp WHERE deptno = 20 FOR UPDATE OF sal; v_sal emp.sal%TYPE; BEGIN OPEN cur_emp; FETCH cur_emp INTO v_sal; LOOP EXIT WHEN cur_emp%NOTFOUND; IF v_sal < 2000 THEN UPDATE emp SET sal = 2000 WHERE current OF cur_emp; --更新当前数据 END IF; FETCH cur_emp INTO v_sal; END LOOP; DBMS_OUTPUT.PUT_LINE('命令执行完毕'); IF cur_emp%ISOPEN THEN CLOSE cur_emp; IF cur_emp%ISOPEN THEN DBMS_OUTPUT.PUT_LINE('Cursor state : Open'); CLOSE cur_emp; ELSE DBMS_OUTPUT.PUT_LINE('Cursor state : Close'); END IF; END IF; END; / --隐式游标--------------------------------------------------------- --不能显式的使用OPEN、CLOSE和FETCH语句,他会自动完成 DECLARE no emp.empno%TYPE; name emp.ename%TYPE; BEGIN SELECT empno,ename INTO no,name FROM emp WHERE empno = '7788'; IF SQL%ISOPEN THEN DBMS_OUTPUT.PUT_LINE('Cursor state : Open'); ELSE DBMS_OUTPUT.PUT_LINE('Cursor state : Close'); END IF; DBMS_OUTPUT.PUT_LINE(no || ' ' || name); DBMS_OUTPUT.PUT_LINE('Return rows : ' || SQL%ROWCOUNT); EXCEPTION WHEN CURSOR_ALREADY_OPEN THEN DBMS_OUTPUT.PUT_LINE('Cursor already open'); WHEN NO_DATA_FOUND THEN DBMS_OUTPUT.PUT_LINE('No data found'); WHEN TOO_MANY_ROWS THEN DBMS_OUTPUT.PUT_LINE('Return many rows'); END; / --游标变量(一个游标变量可以在一个PL\SQL块中使用多次)--------------------------- DECLARE TYPE refcur IS REF CURSOR; --[RETURN TYPE] cur_emp refcur; --引用游标 dept emp.deptno%TYPE; name emp.ename%TYPE; BEGIN OPEN cur_emp FOR SELECT deptno FROM emp WHERE empno = '7788'; FETCH cur_emp INTO dept; DBMS_OUTPUT.PUT_LINE('Dept : ' || dept); CLOSE cur_emp; OPEN cur_emp FOR SELECT ename FROM emp WHERE empno = '7788'; FETCH cur_emp INTO name; DBMS_OUTPUT.PUT_LINE('Name : ' || name); CLOSE cur_emp; END; / --游标在三种循环中的使用------------------------------------------- --001--Loop DECLARE CURSOR cur_emp IS SELECT ename FROM emp; v_name emp.ename%TYPE; BEGIN OPEN cur_emp; FETCH cur_emp INTO v_name; LOOP EXIT WHEN cur_emp%NOTFOUND; DBMS_OUTPUT.PUT_LINE('Name is : ' || v_name); FETCH cur_emp INTO v_name; END LOOP; DBMS_OUTPUT.PUT_LINE('Return rows : ' || cur_emp%ROWCOUNT); CLOSE cur_emp; END; / --002--While DECLARE CURSOR cur_emp IS SELECT ename FROM emp; v_name emp.ename%TYPE; BEGIN OPEN cur_emp; FETCH cur_emp INTO v_name; WHILE cur_emp%FOUND LOOP DBMS_OUTPUT.PUT_LINE('Name is : ' || v_name); FETCH cur_emp INTO v_name; END LOOP; DBMS_OUTPUT.PUT_LINE('Return rows : ' || cur_emp%ROWCOUNT); CLOSE cur_emp; END; / --003--For --注:在使用 FOR 循环时,不能显式的使用 open、colse 和 FETCH 语句,他会自动完成 DECLARE rows number := 0; CURSOR cur_emp IS SELECT ename FROM emp; BEGIN FOR v_emp in cur_emp LOOP DBMS_OUTPUT.PUT_LINE('name is : ' || v_emp.ename); rows := rows + 1; END LOOP; DBMS_OUTPUT.PUT_LINE('Return rows : ' || rows); END; / --OOP Conception--------------------------------------------------- --001 --创建对象类型(相当于C中的结构体,可实现代码重用机制)--- --**注意:OR REPLACE表示将覆盖此用户下的同名对象类型,在不熟悉数据库结构的时候不要滥用 CREATE OR REPLACE TYPE t_score AS OBJECT ( java number(5,2), net number(5,2) ) / --可指定类型名称直接创建对象表 CREATE TABLE score OF t_score; --或应用于表中 CREATE TABLE student ( id VARCHAR2(4), name VARCHAR2(20), score t_score ); --为上表插入数据(利用构造函数) INSERT INTO student VALUES('s101','张三',t_score(85,76)); --或 INSERT INTO student(id,name,score) VALUES('s102','李四',t_score(80,89)); --查询指定 SELECT s.score.java FROM student s; --必须赋予别名 --002 --或者可以创建更为复杂的对象类型,即类型嵌套 CREATE OR REPLACE TYPE t_stu AS OBJECT ( id VARCHAR2(4), name VARCHAR2(20), score t_score ) / --应用于表中 CREATE TABLE student ( stu_base t_stu, teacher varchar2(20) ); --查看表结构 SET DESC DEPTH ALL; --指定查看层次,否则只能看到第一层 DESC student; --插入数据 INSERT INTO student VALUES(t_stu('s101','zhao',t_score(76,81)),'zhang'); --查询指定 SELECT s.stu_base.score.java FROM student s WHERE s.stu_base.id = 's101'; --修改对象类型(注:修改对象类型需9i以上版本)------------------------ --其中INVALIDATE选项使得所有依赖于t_stu类型的对象和表标记为invalid --增加属性address,注:修改后可能引起一些未知的错误,所以请不要随意修改 ALTER TYPE t_stu ADD ATTRIBUTE address VARCHAR2(50) INVALIDATE; --删除类型(注:需按嵌套逐级删除) DROP TYPE t_stu; DROP TYPE t_score; --继承------------------------------------------------------------- --创建一个不可被继承的类型 CREATE OR REPLACE TYPE super_TYPE AS OBJECT ( n NUMBER, FINAL MEMBER PROCEDURE cannot_override ) NOT FINAL / --继承时将出错,可用【SHOW ERROR】语句查看错误信息 CREATE OR REPLACE TYPE sub_TYPE UNDER super_TYPE ( OVERRIDING MEMBER PROCEDURE cannot_override ) / --创建一个不可被实例化、不可被继承的类型 CREATE OR REPLACE TYPE shape AS OBJECT ( n NUMBER, NOT INSTANTIABLE MEMBER FUNCTION calculate_area RETURN NUMBER ) NOT INSTANTIABLE NOT FINAL / --实例化改类型将出错 DECLARE l_shape shape; BEGIN l_shape := shape(2); END; / --嵌套表(表中之表)------------------------------------------------- --创建类型,(以下实例将创建一组动物饲养员嵌套表) CREATE TYPE animal_ty AS OBJECT ( breed VARCHAR2(25), name VARCHAR2(25), birthdate DATE ); / --此类型将用作一个嵌套表的基础类型 CREATE TYPE animal_nt AS TABLE OF animal_ty; / --创建嵌套表 CREATE TABLE breeder ( breedername VARCHAR2(25), animals animal_nt ) NESTED TABLE animals STORE AS animals_nt_tab; --animals_nt_tab代表别名 --插入数据 INSERT INTO breeder VALUES('Mary', animal_nt ( animal_ty('dog','butch',to_date('2004-3-31','yyyy-mm-dd')), animal_ty('dog','rover',to_date('2005-8-20','yyyy-mm-dd')), animal_ty('dog','julio',sysdate) ) ); INSERT INTO breeder VALUES('Jane', animal_nt ( animal_ty('cat','an',to_date('2005-10-12','yyyy-mm-dd')), animal_ty('cat','jame',to_date('2002-1-23','yyyy-mm-dd')), animal_ty('cat','killer',to_date('2004-6-2','yyyy-mm-dd')) ) ); --查询表中姓名为Jane所养的动物 SELECT breed,name,birthdate FROM TABLE(SELECT animals FROM breeder WHERE breedername='Jane'); --可变数组(类似于嵌套表,概念上讲它是限定了行集合的嵌套表)---------- --创建类型(以下实例将创建一组联系人嵌套表) CREATE TYPE comm_info AS OBJECT ( no NUMBER(3), --通讯类型号 comm_TYPE VARCHAR2(20), --通讯类型 comm_no VARCHAR2(30) --号码 ) / --创建可变数组 CREATE TYPE comm_info_list AS VARRAY(50) OF comm_info; / --创建表 CREATE TABLE user_info ( user_id NUMBER(6), --用户ID user_name VARCHAR2(20), --用户名 user_comm comm_info_list --与用户联系的通讯方式 ); --插入数据 INSERT INTO user_info VALUES(101,'Mary', comm_info_list(comm_info(1,'手机','13652369888'), comm_info(2,'座机','02125689366'))); INSERT INTO user_info VALUES(102,'Tom', comm_info_list(comm_info(1,'手机','13765235898'), comm_info(2,'座机','021-65234789'))); --查询用户ID为101的手机号码 SELECT comm_type,comm_no FROM TABLE(SELECT user_comm FROM user_info WHERE user_id = 101) WHERE no = 1; --对象表----------------------------------------------------------- --创建对象 CREATE OR REPLACE TYPE address AS OBJECT ( id NUMBER(4), street VARCHAR2(50), state VARCHAR2(2), zip VARCHAR2(11) ) / --创建对象表 CREATE TABLE address_table OF address; --插入数据 INSERT INTO address_table VALUES(1,'Oracle way','US','90001'); --或使用构造函数 INSERT INTO address_table VALUES(address(2,'Microsoft way','US','80863')); --查询数据 SELECT * FROM address_table; --VALUE关键字:以对象表别名做参数,返回对象实例 SELECT VALUE(a) FROM address_table a; --REF数据类型:在关系表中关联对象 CREATE TABLE employee_location ( empno NUMBER, loc_ref REF address SCOPE IS address_table --此列引用了类型address ); --查看结构 SET DESC DEPTH ALL; DESC employee_location; --REF()函数:将引用对象表中的数据插入 INSERT INTO employee_location SELECT 101,REF(a) FROM address_table a WHERE id = 1; INSERT INTO employee_location SELECT 102,ref(a) FROM address_table a WHERE id = 2; --查询 --注:用此语句查询的结果是未解析过的REF数据 SELECT * FROM employee_location --DEREF():解析REF数据,返回真正指向的实例 SELECT empno,DEREF(loc_ref) FROM employee_location; --悬空REF:REF指向的对象实例被删除了,此时成为REF悬空(dangling),说明REF指向不存在的实例 DELETE FROM address_table WHERE id = 2; --查询 --悬空的REF会返回NULL,使用 IS DANGLING 确定那些REF悬空 SELECT empno FROM employee_location WHERE loc_ref IS DANGLING; --清除悬空的REF,将REF更新未NULL UPDATE employee_location SET loc_ref = NULL WHERE loc_ref IS DANGLING; --再查看:已经将悬空的REF清除 SELECT * FROM employee_location; --对象视图--------------------------------------------------------- --创建表--关系表 CREATE TABLE item ( item_code VARCHAR2(10), item_hand NUMBER(10), item_sode NUMBER(10) ); --创建对象--使用相同列 CREATE OR REPLACE TYPE item_type AS OBJECT ( item_code VARCHAR2(10), item_hand NUMBER(10), item_sode NUMBER(10) ) / --建立对象视图 CREATE VIEW item_view OF item_type --OF item_type 说明基于对象 WITH OBJECT OID(item_code) --WITH OBJECT OID(item_code)明确生成OID AS SELECT * FROM item / --我们现在可以通过视图来操作数据 INSERT INTO item_view VALUES(item_type('i101',15,50)); --MAKE_REF() --关系主表 CREATE TABLE itemfile ( itemcode VARCHAR2(5) PRIMARY KEY, itemdesc VARCHAR2(20), p_category VARCHAR2(20), qty_hand NUMBER(5), re_level NUMBER(5), max_level NUMBER(5), itemrate NUMBER(9,2) ); --关系从表 CREATE TABLE order_detail ( orderno VARCHAR2(5), itemcode VARCHAR2(5), qty_ord NUMBER(5), qty_deld NUMBER(5) ); --PL/SQL表和记录--------------------------------------------------- SET SERVEROUTPUT ON; DECLARE TYPE rec_emp IS RECORD --定义记录 ( no emp.empno%TYPE, name emp.ename%TYPE ); TYPE tab_emp IS TABLE OF rec_emp --定义 PL/SQL 表 INDEX BY binary_integer; i NUMBER := 1; temp_emp tab_emp; --定义 PL/SQL 表的变量 CURSOR cur_emp IS SELECT empno,ename FROM emp; BEGIN OPEN cur_emp; FETCH cur_emp INTO temp_emp(i); LOOP EXIT WHEN cur_emp%NOTFOUND; DBMS_OUTPUT.PUT_LINE(temp_emp(i).no || ' ' || temp_emp(i).name); i := i + 1; FETCH cur_emp INTO temp_emp(i); END LOOP; DBMS_OUTPUT.PUT_LINE('总计打印了 ' || temp_emp.count || ' 条记录'); CLOSE cur_emp; END; / ----------------------------------------------------------------------------------End
posted @
2010-06-08 18:51
借我一生
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