| Oracle中有两种集合，分别是嵌套表和VARRAY
它们在存储的数据类型方面具有相似之处，因为它们都可以包含对象，两者的区别为：
嵌套表
．尺寸没有限制。
．本质上是无序的
VARRAY
．尺寸必须固定，所有的实例尺寸相同。
．在过程化语言中可以作为有序数组进行检索但在Oracle内部看成单个不能分割的单元。
．存储效率高。 --------------------------------------------------
--嵌套表
CREATE TYPE SCORE_NESTED AS TABLE OF NUMBER; -------------------------------------------------
--在表中使用嵌套表
CREATE TABLE PLAYER(
GUID NUMBER,
NAME VARCHAR2(20),
SCORE SCORE_NESTED
)
NESTED TABLE SCORE STORE AS PLAYER_SCORE; CREATE OR REPLACE TRIGGER PLAYER_T_I1
BEFORE INSERT ON PLAYER REFERENCING NEW AS NEW OLD AS OLD FOR EACH ROW
BEGIN
:NEW.GUID := XLING_PKG_TOOLS.F_GET_NEXTVAL('PLAYER');
END; CREATE OR REPLACE TRIGGER PLAYER_T_D1
BEFORE UPDATE ON PLAYER REFERENCING NEW AS NEW OLD AS OLD FOR EACH ROW
BEGIN
XLING_PKG_TOOLS.P_DELETE_GUID(:OLD.GUID);
END; -------------------------------------------------
--向嵌套表中插入数据．
INSERT INTO PLAYER (NAME,SCORE) VALUES ('xling',SCORE_NESTED(100,100,98,105,90))
INSERT INTO PLAYER (NAME,SCORE) VALUES ('snow',SCORE_NESTED(105,98,90,100,90)); SELECT * FROM PLAYER
-------------------------------------------------
--追加数据
INSERT INTO TABLE(SELECT SCORE FROM PLAYER WHERE NAME = 'xling') VALUES (110);
--INSERT INTO TABLE(SELECT SCORE FROM PLAYER WHERE NAME = 'snow') VALUES (SCORE_NESTED(100,100));
--ORA-00932: 数据类型不一致: 应为 NUMBER, 但却获得 XLING.SCORE_NESTED
-------------------------------------------------
--选出套表数据
SELECT * FROM TABLE(SELECT SCORE FROM PLAYER WHERE NAME = 'xling')--SELECT * FROM TABLE(SELECT SCORE FROM PLAYER) 错误：ORA-01427:单行子查询返回多行
-------------------------------------------------
--更新套表
UPDATE PLAYER SET SCORE = SCORE_NESTED(100,200) WHERE NAME = 'xling'
SELECT * FROM TABLE(SELECT SCORE FROM PLAYER WHERE NAME = 'xling');
-------------------------------------------------
--删除套表
UPDATE PLAYER SET SCORE = NULL WHERE NAME = 'xling'SELECT * FROM TABLE(SELECT SCORE FROM PLAYER WHERE NAME = 'xling');
--INSERT INTO TABLE(SELECT SCORE FROM PLAYER WHERE NAME = 'xling') VALUES (200)
--由于以把记录中的套表删除了，所以会引发：ORA-22908: NULL 表值的参考
-------------------------------------------------
DROP TABLE PLAYER
DROP TYPE SCORE_NESTED CREATE TYPE SCORE_TYPE AS OBJECT(
NO NUMBER,
ITEM VARCHAR2(60),
SCORE NUMBER
) CREATE TYPE SCORE_NESTED AS TABLE OF SCORE_TYPE; CREATE TABLE PLAYER(
GUID NUMBER,
NAME VARCHAR2(20),
SCORE SCORE_NESTED
)
NESTED TABLE SCORE STORE AS SCORE_NESTED_TABLE CREATE OR REPLACE TRIGGER PLAYER_T_I1
BEFORE INSERT ON PLAYER REFERENCING NEW AS NEW OLD AS OLD FOR EACH ROW
BEGIN
:NEW.GUID := XLING_PKG_TOOLS.F_GET_NEXTVAL('PLAYER');
END; CREATE OR REPLACE TRIGGER PLAYER_T_D1
BEFORE UPDATE ON PLAYER REFERENCING NEW AS NEW OLD AS OLD FOR EACH ROW
BEGIN
XLING_PKG_TOOLS.P_DELETE_GUID(:OLD.GUID);
END; INSERT INTO PLAYER (NAME,SCORE) VALUES ('xling',SCORE_NESTED(
SCORE_TYPE(1,'上山',100),
SCORE_TYPE(2,'下海',100),
SCORE_TYPE(3,'摸鱼',90),
SCORE_TYPE(4,'骑猪',80)
))
INSERT INTO PLAYER (NAME,SCORE) VALUES ('werewi',SCORE_NESTED(
SCORE_TYPE(1,'泡妞',100),
SCORE_TYPE(2,'考研',150),
SCORE_TYPE(3,'摸鱼',90)
))
SELECT * FROM TABLE(SELECT SCORE FROM PLAYER WHERE NAME = 'xling');
SELECT * FROM TABLE(SELECT SCORE FROM PLAYER WHERE NAME = 'werewi'); SELECT 'xling',S.ITEM,S.SCORE FROM TABLE(SELECT SCORE FROM PLAYER WHERE NAME = 'xling') S
UNION ALL
SELECT 'werewi',S.ITEM,S.SCORE FROM TABLE(SELECT SCORE FROM PLAYER WHERE NAME = 'werewi') S ---------------------------------------------------------------------------------------------------
/*
SET SERVEROUTPUT ON
DECLARE
V_NAME VARCHAR2(20);
V_SQL VARCHAR2(32767);
BEGIN
V_SQL := '';
FOR CC IN (SELECT NAME FROM PLAYER) LOOP
V_SQL := V_SQL || 'SELECT ''' || CC.NAME || ''',S.ITEM,S.SCORE FROM TABLE(SELECT SCORE FROM PLAYER WHERE NAME = '''|| CC.NAME ||''') S UNION ALL ';
END LOOP;
V_SQL := V_SQL || 'SELECT NULL,NULL,NULL FROM DUAL';
DBMS_OUTPUT.PUT_LINE(V_SQL);
EXECUTE IMMEDIATE V_SQL;
DBMS_OUTPUT.PUT_LINE(SQL%ROWCOUNT);
END;
*/
----------------------------------------------------------------------------------------------------
-- 选出所有记录
SELECT
GUID,NAME,S.*
FROM
PLAYER P,
TABLE(P.SCORE) S |
