一、抽象数据类型
1、创建类型 --地址类型 CREATE OR REPLACE TYPE AddressType AS OBJECT ( Country varchar2(15), City varchar2(20), Street varchar2(30) ); 2、类型嵌套 --创建基于前一个类型的新的抽象数据类型:巨星类型 CREATE OR REPLACE TYPE SuperStarType AS OBJECT ( StarName varchar2(30), Address AddressType ); 3、基于抽象类型创建关系表 CREATE TABLE SuperStar ( StarID varchar(10), Star SuperStarType ); 4、基于抽象类型创建对象表 CREATE TABLE SuperStarObj of SuperStarType; 5、使用构造方法在表中插入记录 INSERT INTO SuperStar VALUES(''001'',SuperStarType(''Zidane'',AddressType(''France'',''Paris'',''People Street NO.1''))); 6、查询表中记录 (1)SQL> SELECT * FROM SuperStar; STARID ---------- STAR(STARNAME, ADDRESS(COUNTRY, CITY, STREET)) -------------------------------------------------------------------------------- 001 SUPERSTARTYPE(''Zidane'', ADDRESSTYPE(''France'', ''Paris'', ''People Street NO.1'')) (2) SELECT s.StarID,s.Star.StarName,s.Star.Address.Country,s.Star.Address.City,s.Star.Address.Street FROM SuperStar s STARID STAR.STARNAME STAR.ADDRESS.CO STAR.ADDRESS.CITY STAR.ADDRESS.STREET ---------- ------------------------------ --------------- -------------------- --------------------- 001 Zidane France Paris People Street NO.1 7、抽象数据类型的继承 (1)创建一个类型 CREATE OR REPLACE TYPE PersonType AS OBJECT ( PersonName varchar(10), PersonSex varchar(2), PersonBirth date ) not final; (2)派生一个类型 CREATE OR REPLACE TYPE StudentType UNDER PersonType ( StudentNO int, StudentScore int ); (3)查看数据字典 SQL> DESC StudentType StudentType extends SYS.PERSONTYPE Name ------------------------------------------------------------------------------ PERSONNAME PERSONSEX PERSONBIRTH STUDENTNO STUDENTSCORE (4)创建对象表 CREATE TABLE student OF StudentType; (5)向对象表中插入数据 INSERT INTO student VALUES(''Rose'',''nv'',to_date(''1983-05-02'',''yyyy-mm-dd''),1001,98); (6) 查询数据 SQL> SELECT * FROM student; PERSONNAME PE PERSONBIR STUDENTNO STUDENTSCORE ---------- -- --------- ---------- ------------ Rose nv 02-MAY-83 1001 98 二、可变数组 1、创建带有可变数组的表 (1)创建可变数组的基类型 CREATE OR REPLACE TYPE MingXiType AS OBJECT ( GoodID varchar2(20), InCount int, ProviderID varchar(20) ); (2)创建嵌套项类型的可变数组 CREATE OR REPLACE TYPE arrMingXiType AS VARRAY(100) OF MingXiType; (3)创建一个主表 CREATE TABLE InStockOrder ( OrderID varchar(15) Not Null Primary Key, InDate date, OperatorID varchar(15), MingXi arrMingXiType ); 2、操作可变数组 (1)插入数据 INSERT INTO InStockOrder VALUES(''200710110001'',TO_DATE(''2007-10-11'',''YYYY-MM-DD''),''007'', arrMingXiType(MingXiType(''G001'',100,''1001''), MingXiType(''G002'',888,''1002'')) ); (2)查询数据 SQL> SELECT * FROM InStockOrder; ORDERID INDATE OPERATORID --------------- --------- --------------- MINGXI(GOODID, INCOUNT, PROVIDERID) ---------------------------------------------------------------------- 200710110001 11-OCT-07 007 ARRMINGXITYPE(MINGXITYPE(''G001'', 100, ''1001''), MINGXITYPE(''G002'', 888, ''1002'') (3)使用Table()函数 SQL> SELECT * FROM Table(SELECT t.MingXi FROM InStockOrder t WHERE t.OrderID=''200710110001''); GOODID INCOUNT PROVIDERID -------------------- ---------- -------------------- G001 100 1001 G002 888 1002 (4)修改数据 UPDATE InStockOrder SET MingXi=arrMingXiType(MingXiType(''G001'',200,''1001''), MingXiType(''G002'',8888,''1002'')) WHERE OrderID=''200710110001'' 注意:不能更新VARRAY中的单个元素,必须更新整个VARRAY 三、嵌套表 1、创建嵌套表 (1)创建嵌套表的基类型 CREATE OR REPLACE TYPE MingXiType AS OBJECT ( GoodID varchar2(20), InCount int, ProviderID varchar(20) ) not final; (2)创建嵌套表类型 CREATE OR REPLACE TYPE nestMingXiType AS TABLE OF MingXiType; (3)创建主表,其中一列是嵌套表类型 CREATE TABLE InStockTable ( OrderID varchar(15) Not Null Primary Key, InDate date, OperatorID varchar(15), MingXi nestMingXiType ) Nested Table MingXi STORE AS MingXiTable; 2、操作嵌套表 (1)向嵌套表中插入记录 INSERT INTO InStockTable VALUES(''20071012001'',TO_DATE(''2007-10-12'',''YYYY-MM-DD''),''007'', nestMingXiType(MingXiType(''G003'',666,''1001''), MingXiType(''G004'',888,''1002''), MingXiType(''G005'',8888,''1003'')) ); (2)查询数据 SQL> SELECT * FROM InStockTable; ORDERID INDATE OPERATORID --------------- --------- --------------- MINGXI(GOODID, INCOUNT, PROVIDERID) ---------------------------------------------------------------------------------------------------- 20071012001 12-OCT-07 007 NESTMINGXITYPE(MINGXITYPE(''G003'', 666, ''1001''), MINGXITYPE(''G004'', 888, ''1002''), MINGXITYPE(''G005'', 8888, ''1003'') (3)使用Table()函数 SQL> SELECT * FROM Table(SELECT T.MingXi FROM InStockTable t WHERE OrderID=''20071012001'') GOODID INCOUNT PROVIDERID -------------------- ---------- -------------------- G003 666 1001 G004 888 1002 G005 8888 1003 (4)更新嵌套表中的数据 UPDATE Table(SELECT t.MingXi FROM InStockTable t WHERE OrderID=''20071012001'') tt SET tt.InCount=1666 WHERE tt.GoodID=''G003''; (5)删除表中数据 DELETE Table(SELECT t.MingXi FROM InStockTable t WHERE OrderID=''20071012001'') tt WHERE tt.GoodID=''G003'' 四、对象表 1、创建对象表 CREATE TABLE ObjectTable OF MingXiType; 2、向表中插入数据 INSERT INTO ObjectTable VALUES(''G001'',500,''P005''); INSERT INTO ObjectTable VALUES(''G002'',1000,''P008''); 3、查询对象表中的记录 A 直接查询 SQL> SELECT * FROM ObjectTable; GOODID INCOUNT PROVIDERID -------------------- ---------- --------------- G001 500 P005 G002 1000 P008 B 用VALUE()函数查询 SQL> SELECT VALUE(O) FROM ObjectTable O; VALUE(O)(GOODID, INCOUNT, PROVIDERID) ------------------------------------------ MINGXITYPE(''G001'', 500, ''P005'') MINGXITYPE(''G002'', 1000, ''P008'') 4、查看对象标志符(OID) A REF操作符引用行对象 SQL> SELECT REF(t) FROM ObjectTable t; REF(T) -------------------------------------------------------------------------------- 0000280209771F103ED34842478A9C439CDAEFEF6324B0ACF849F14BD7A8B52F4B0297D1C90040A9 5A0000 0000280209A2D3359E0F0C44B3AF652B944F8823F524B0ACF849F14BD7A8B52F4B0297D1C90040A9 5A0001 B 将OID用于创建外键 CREATE TABLE Customer ( CustomerID varchar(10) PRIMARY KEY, CustomerName varchar(20), CustomerGoods REF MingXiType SCOPE IS ObjectTable,--引用MingXiType外键,关联的是OID的值 CustomerAddress varchar(20) ); C 向Customer表中插入数据,此表将从上面创建的对象表中引用数据 INSERT INTO Customer SELECT ''007'',''Yuanhy'',REF(O),''France'' FROM ObjectTable O WHERE GoodID=''G001''; D 查询Customer表 SQL> SELECT * FROM Customer; CUSTOMERID CUSTOMERNAME ---------- -------------------- CUSTOMERGOODS ----------------------------------------------------------------------------- CUSTOMERADDRESS -------------------- 007 Yuanhy 0000220208771F103ED34842478A9C439CDAEFEF6324B0ACF849F14BD7A8B52F4B0297D1C9 France E 用DEREF操作符返回对象的值 SQL> SELECT CustomerID,CustomerName,DEREF(t.CustomerGoods),CustomerAddress 2 FROM Customer t; CUSTOMERID CUSTOMERNAME ---------- -------------------- DEREF(T.CUSTOMERGOODS)(GOODID, INCOUNT, PROVIDERID) ---------------------------------------------------------------------------- CUSTOMERADDRESS -------------------- 007 Yuanhy MINGXITYPE(''G001'', 500, ''P005'') France 五、对象视图 将关系表化装成对象表 1、 创建对象视图 A 创建基于关系表父表的对象类型 CREATE OR REPLACE TYPE depttype AS OBJECT ( deptid number(10), deptname varchar(30), loc number(10) ); B 创建基于关系表的对象视图 CREATE VIEW deptview OF depttype WITH OBJECT OID(deptid) AS SELECT department_id,department_name,location_id FROM dept; C 查询视图 SQL> SELECT * FROM deptview; DEPTID DEPTNAME LOC ---------- ------------------------------ ---------- 10 Administration 1700 20 Marketing 1800 30 Purchasing 1700 40 Human Resources 2400 50 Shipping 1500 60 IT 1400 70 Public Relations 2700 SQL> select ref(t) from deptview t; REF(T) ---------------------------------------------------------------------------------------------------- 00004A038A004667BAC3685B444520A60ED30027E8F25F0000001426010001000100290000000000090604002A00078401FE 00004A038A004667BAC3685B444520A60ED30027E8F25F0000001426010001000100290000000000090604002A00078401FE 00004A038A004667BAC3685B444520A60ED30027E8F25F0000001426010001000100290000000000090604002A00078401FE 00004A038A004667BAC3685B444520A60ED30027E8F25F0000001426010001000100290000000000090604002A00078401FE 00004A038A004667BAC3685B444520A60ED30027E8F25F0000001426010001000100290000000000090604002A00078401FE 00004A038A004667BAC3685B444520A60ED30027E8F25F0000001426010001000100290000000000090604002A00078401FE 00004A038A004667BAC3685B444520A60ED30027E8F25F0000001426010001000100290000000000090604002A00078401FE 2、创建引用视图(类似于关系表创建一个从表) CREATE VIEW empview AS SELECT MAKE_REF(deptview,department_id) deptOID,employee_id, first_name,last_name FROM emp; 查询对象视图empview SQL> SELECT * FROM empview; DEPTOID ---------------------------------------------------------------------------------------------------- EMPLOYEE_ID FIRST_NAME LAST_NAME ----------- -------------------- ------------------------- 00004A038A004667BAC3685B444520A60ED30027E8F25F0000001426010001000100290000000000090604002A00078401FE 100 Steven King 00004A038A004667BAC3685B444520A60ED30027E8F25F0000001426010001000100290000000000090604002A00078401FE 101 Neena Kochhar 00004A038A004667BAC3685B444520A60ED30027E8F25F0000001426010001000100290000000000090604002A00078401FE 102 Lex De Haan 00004A038A004667BAC3685B444520A60ED30027E8F25F0000001426010001000100290000000000090604002A00078401FE 103 Alexander Hunold
Oracle对象类型也有属性和方法.
创建对象类型与创建表很相似,只是实际上不为存储的数据分配空间:
不带方法的简单对象类型:
CREATE TYPE type_name as OBJECT ( column_1 type1, column_2 type2, ... ); 注意:AS OBJECT
创建好对象类型之后,就可以在创建表的时候,使用该类型了,如:
CREATE TYPE HUMAN AS OBJECT( NAME VARCHAR2(20), SEX VARCHAR2(1),-- F : FEMALE M:MALE BIRTHDAY DATE, NOTE VARCHAR2(300) )
稍后,可以用下面的语句查看:
SELECT * FROM USER_OBJECTS WHERE OBJECT_TYPE = ''TYPE'' CREATE TABLE STUDENTS( GUID NUMBER NOT NULL, STUDENTS HUMAN ) 此下省去两个Trigger. 插入数据的时候,可以如下: INSERT INTO STUDENTS (STUDENT) VALUES (HUMAN(''xling'',''M'',TO_DATE(''20060101'',''YYYYMMDD''),''测试''))
注意:HUMAN(''xling'',''M'',TO_DATE(''20060101'',''YYYYMMDD''),''测试''),这是个默认的构造函数.
如果想选出性别为女(F)的记录,可以如下: SELECT * FROM STUDENTS S WHERE S.STUDENT.SEX = ''F''
注意:不能写成:SELECT * FROM STUDENTS WHERE STUDENT.SEX = ''F'' 这样会报如下错误:ORA-00904: "STUDENT"."SEX": 标识符无效
对象类型表:每条记录都是对象的表,称为对象类型表.它有两个使用方法:1,用作只有一个对象类型字段的表.2,用作具有对象类型字段的标准关系表. 语法如下: CREATE TABLE table_name OF object_type;
例如:
CREATE TABLE TMP_STUDENTS OF HUMAN;
用DESC TMP_STUDENTS,可以看到它的字段结构和HUMAN的结构一样.
对象类型表有两个优点:1,从某种程度上简化了对象的使用,因为对象表的字段类型与对象类型是一致的,所以,不需要用对象名来修饰对象属性,可以把数据插入对象类型表,就像插入普通的关系表中一样:
INSERT INTO TMP_STUDENTS VALUES (''xling'',''M'',TO_DATE(''20060601'',''YYYYMMDD''),''对象类型表'');
当然也可用如下方法插入: INSERT INTO TMP_STUDENTS VALUES (HUMAN(''snow'',''F'',TO_DATE(''20060102'',''YYYYMMDD''),''用类型的构造函数'')); 第二个特点是:对象表是使用对象类型作为模板来创建表的一种便捷方式,它可以确保多个表具有相同的结构.
对象类型表在:USER_TABLES表里是查不到的,而在USER_OBJECTS表里可以查到,而且OBJECT_TYPE = ''TABLE''
类型在定义的时候,会自动包含一个方法,即默认的构造器.构造器的名称与对象的名称相同,它带有变量与对象类型的每个属性相对应.
对象类型的方法: CREATE TYPE type_name AS OBJECT ( column1 column_type1, column2 column_type2, ... , MEMBER FUNCTION method_name(args_list) RETURN return_type, ... ) 注意:是MEMBER FUNCTION,(当然,也可是MEMBER PROCEDURE,没有返回值)
和包(PACKAGE)一样,如果对象类型有方法的话,还要声明一个BODY:
CREATE TYPE BODY type_name AS MEMBER FUNCTION method_name RETURN return_type {AS | IS} variable declareations.. BEGIN CODE.. RETURN return_value; END;//END MEMBER FUNCTION ... END;//END TYPE BODY 如下所示: CREATE TYPE HUMAN AS OBJECT( NAME VARCHAR2(20), SEX VARCHAR2(1),-- F : FEMALE M:MALE BIRTHDAY DATE, NOTE VARCHAR2(300), MEMBER FUNCTION GET_AGE RETURN NUMBER )
--BODY
CREATE TYPE BODY HUMAN AS MEMBER FUNCTION GET_AGE RETURN NUMBER AS V_MONTHS NUMBER; BEGIN SELECT FLOOR(MONTHS_BETWEEN(SYSDATE,BIRTHDAY)/12) INTO V_MONTHS FROM DUAL; RETURN V_MONTHS; END; END; 注意:BODY的格式,不是AS OBJECT,也不是用小括号括起来的.MEMBER FUNCTION 后的AS或IS不能省略. 还以STUDENTS表为例(注:如果类型以被某个表使用,是不能修改的,必须把相关的表删除,然后把类型删除,在一个一个新建,这里就省略了,参见前文所述)
SELECT S.STUDENT.GET_AGE() FROM STUDENTS S
在提起注意:表名一定要有别名.GET_AGE()的括号不能省略,否则会提示错误.
下面演示在一个匿名过程中的使用情况:
SET SERVEROUTPUT ON
DECLARE AA HUMAN; AGE NUMBER; BEGIN AA := HUMAN(''xingFairy'',''M'',TO_DATE(''19830714'',''YYYYMMDD''),''过程''); AGE := AA.GET_AGE(); DBMS_OUTPUT.PUT_LINE(AGE); END; 映射方法: 映射方法是一种不带参数,并返回标准的标量Oracle SQL数据类型的方法,如NUMBER,VARCHAR2,Oracle将间接地使用这些方法执行比较运算. 映射方法最重要的一个特点是:当在WHERE或ORDER BY等比较关系子句中使用对象时,会间接地使用映射方法. 映射方法的声明只过是在普通方法声明的前面加一个 MAP而以,注意:映射方法是一种不带参数的方法. MAP MEMBER FUNCTION function_name RETURN return_type
修改前文提到的HUMAN类型:
--映射方法 MAP CREATE TYPE HUMAN AS OBJECT( NAME VARCHAR2(20), SEX VARCHAR2(1),-- F : FEMALE M:MALE BIRTHDAY DATE,--注册日期 REGISTERDAY DATE, NOTE VARCHAR2(300), MEMBER FUNCTION GET_AGE RETURN NUMBER, MAP MEMBER FUNCTION GET_GRADE RETURN NUMBER )
CREATE TYPE BODY HUMAN AS
----------------------- MEMBER FUNCTION GET_AGE RETURN NUMBER AS V_MONTHS NUMBER; BEGIN SELECT FLOOR(MONTHS_BETWEEN(SYSDATE,BIRTHDAY)/12) INTO V_MONTHS FROM DUAL; RETURN V_MONTHS; END; ------------------------ MAP MEMBER FUNCTION GET_GRADE RETURN NUMBER AS BEGIN RETURN MONTHS_BETWEEN(SYSDATE,BIRTHDAY); END; END;
插入数据:
INSERT INTO STUDENTS (STUDENT) VALUES (HUMAN(''xling'',''M'',TO_DATE(''19830714'',''YYYYMMDD''),TO_DATE(''20020915'',''YYYYMMDD''),''测试MAP方法'')); INSERT INTO STUDENTS (STUDENT) VALUES (HUMAN(''fairy'',''M'',TO_DATE(''19830714'',''YYYYMMDD''),TO_DATE(''20010915'',''YYYYMMDD''),''测试MAP方法'')); INSERT INTO STUDENTS (STUDENT) VALUES (HUMAN(''snow'',''M'',TO_DATE(''19830714'',''YYYYMMDD''),TO_DATE(''20020915'',''YYYYMMDD''),''测试MAP方法'')); 在执行上面的操作后,用下面这个SELECT语句可以看出映射方法的效果: SELECT S.STUDENT.NAME,S.STUDENT.GET_GRADE() FROM STUDENTS S ORDER BY STUDENT 它是按MAP方法GET_GRADE()的值进行排序的.注意是ORDER BY STUDENT,在提起一次需要注意,一定要用表的别名,方法后的括号不能省略,即使没有参数. 如果想以MAP方法的结果为条件,可以如下: SELECT S.STUDENT.NAME,S.STUDENT.GET_GRADE() FROM STUDENTS S WHERE S.STUDENT.GET_GRADE() > 50 SELECT S.STUDENT.NAME,S.STUDENT.GET_GRADE() FROM STUDENTS S WHERE STUDENT > HUMAN(NULL,NULL,NULL,TO_DATE(''20020101'',''YYYYMMDD''),NULL);
排序方法:
先说一下SELF,Oracle里对象的SELF和JAVA里的this是同一个意思. 对象的排序方法具有一个与对象类型相同的参数,暂称为ARG1,用于和SELF对象进行比较.如果调用方法的SELF对象比ARG1小,返回负值,如果相等,返回0,如果SELF大于ARG1,则返回值大于0.
--映射方法 MAP
CREATE TYPE HUMAN AS OBJECT( NAME VARCHAR2(20), SEX VARCHAR2(1),-- F : FEMALE M:MALE BIRTHDAY DATE, REGISTERDAY DATE, NOTE VARCHAR2(300), MEMBER FUNCTION GET_AGE RETURN NUMBER, ORDER MEMBER FUNCTION MATCH(I_STUDENT IN HUMAN) RETURN NUMBER )
CREATE TYPE BODY HUMAN AS
----------------------- MEMBER FUNCTION GET_AGE RETURN NUMBER AS V_MONTHS NUMBER; BEGIN SELECT FLOOR(MONTHS_BETWEEN(SYSDATE,BIRTHDAY)/12) INTO V_MONTHS FROM DUAL; RETURN V_MONTHS; END; ------------------------ ORDER MEMBER FUNCTION MATCH(I_STUDENT IN HUMAN) RETURN NUMBER AS BEGIN RETURN REGISTERDAY - I_STUDENT.REGISTERDAY; END; END;
注意:在声明的时候,ORDER方法的参数类型要和SELF的类型一致.
SET SERVEROUTPUT ON
DECLARE S1 HUMAN; S2 HUMAN; BEGIN S1 := HUMAN(''xling'',NULL,NULL,TO_DATE(''20020915'',''YYYYMMDD''),NULL); S2 := HUMAN(''snow'',NULL,NULL,TO_DATE(''20010915'',''YYYYMMDD''),NULL); IF S1 > S2 THEN DBMS_OUTPUT.PUT_LINE(S1.NAME); ELSIF S1 < S2 THEN DBMS_OUTPUT.PUT_LINE(S2.NAME); ELSE DBMS_OUTPUT.PUT_LINE(''EQUAL''); END IF; END;
注意S1 和 S2是怎么比较的.
映射方法具有效率方面的优势,因为它把每个对象与单个标量值联系在一起;排序方法有灵活方面的优势,它可以在两个对象之间进行任意复杂的比较.排序方法比映射方法的速度慢.
|
转载于http://database.e800.com.cn/articles/2008/57/1210105158753185821_1.html