2011-10-21 自定义异常的捕获

2025-04-13 技术教程

http://www.itpub.net/thread-1499223-7-1.html

70楼

下列的哪些程序块在执行之后会显示："Trapped!"

注意：当你试图把字符串 "13-DEC-2004 6:56 PM" 使用掩码 "DD-MON-YYYY HH:MI:SS" 转换成日期型时，Oracle 会抛出 ORA-01858 错误。

(A)

DECLAREe1EXCEPTION;PRAGMAEXCEPTION_INIT(e1,-1858);BEGINDBMS_OUTPUT.put_line(TO_DATE('13-DEC-20046:56PM','DD-MON-YYYYHH:MI:SS'));EXCEPTIONWHENe1THENDBMS_OUTPUT.put_line('Trapped!');END;/

SQL>DECLARE2e1EXCEPTION;3PRAGMAEXCEPTION_INIT(e1,-1858);4BEGIN5DBMS_OUTPUT.put_line(6TO_DATE('13-DEC-20046:56PM'7,'DD-MON-YYYYHH:MI:SS'));8EXCEPTION9WHENe110THEN11DBMS_OUTPUT.put_line('Trapped!');12END;13/DECLAREe1EXCEPTION;PRAGMAEXCEPTION_INIT(e1,-1858);BEGINDBMS_OUTPUT.put_line(TO_DATE('13-DEC-20046:56PM','DD-MON-YYYYHH:MI:SS'));EXCEPTIONWHENe1THENDBMS_OUTPUT.put_line('Trapped!');END;ORA-01843:无效的月份ORA-06512:在line5SQL>

(B)

DECLAREe1EXCEPTION;PRAGMAEXCEPTION_INIT(e1,-1858);BEGINDECLAREe2EXCEPTION;PRAGMAEXCEPTION_INIT(e2,-1858);BEGINDBMS_OUTPUT.put_line(TO_DATE('13-DEC-20046:56PM','DD-MON-YYYYHH:MI:SS'));END;EXCEPTIONWHENe1THENDBMS_OUTPUT.put_line('Trapped!');END;/

SQL>DECLARE2e1EXCEPTION;3PRAGMAEXCEPTION_INIT(e1,-1858);4BEGIN5DECLARE6e2EXCEPTION;7PRAGMAEXCEPTION_INIT(e2,-1858);8BEGIN9DBMS_OUTPUT.put_line(10TO_DATE('13-DEC-20046:56PM'11,'DD-MON-YYYYHH:MI:SS'));12END;13EXCEPTION14WHENe115THEN16DBMS_OUTPUT.put_line('Trapped!');17END;18/DECLAREe1EXCEPTION;PRAGMAEXCEPTION_INIT(e1,-1858);BEGINDECLAREe2EXCEPTION;PRAGMAEXCEPTION_INIT(e2,-1858);BEGINDBMS_OUTPUT.put_line(TO_DATE('13-DEC-20046:56PM','DD-MON-YYYYHH:MI:SS'));END;EXCEPTIONWHENe1THENDBMS_OUTPUT.put_line('Trapped!');END;ORA-01843:无效的月份ORA-06512:在line9SQL>

(C)

SQL>DECLARE2e1EXCEPTION;3PRAGMAEXCEPTION_INIT(e1,-1858);4BEGIN5DECLARE6e2EXCEPTION;7PRAGMAEXCEPTION_INIT(e2,-1858);8BEGIN9DBMS_OUTPUT.put_line(10TO_DATE('13-DEC-20046:56PM'11,'DD-MON-YYYYHH:MI:SS'));12END;13EXCEPTION14WHENe215THEN16DBMS_OUTPUT.put_line('Trapped!');17END;18/DECLAREe1EXCEPTION;PRAGMAEXCEPTION_INIT(e1,-1858);BEGINDECLAREe2EXCEPTION;PRAGMAEXCEPTION_INIT(e2,-1858);BEGINDBMS_OUTPUT.put_line(TO_DATE('13-DEC-20046:56PM','DD-MON-YYYYHH:MI:SS'));END;EXCEPTIONWHENe2THENDBMS_OUTPUT.put_line('Trapped!');END;ORA-06550:第14行,第9列:PLS-00201:必须声明标识符'E2'ORA-06550:第0行,第0列:PL/SQL:CompilationunitanalysisterminatedSQL>

(D)

DECLAREe1EXCEPTION;BEGINDECLAREPRAGMAEXCEPTION_INIT(e1,-1858);BEGINDBMS_OUTPUT.put_line(TO_DATE('13-DEC-20046:56PM','DD-MON-YYYYHH:MI:SS'));END;EXCEPTIONWHENe1THENDBMS_OUTPUT.put_line('Trapped!');END;/

SQL>DECLARE2e1EXCEPTION;3BEGIN4DECLARE5PRAGMAEXCEPTION_INIT(e1,-1858);6BEGIN7DBMS_OUTPUT.put_line(8TO_DATE('13-DEC-20046:56PM'9,'DD-MON-YYYYHH:MI:SS'));10END;11EXCEPTION12WHENe113THEN14DBMS_OUTPUT.put_line('Trapped!');15END;16/DECLAREe1EXCEPTION;BEGINDECLAREPRAGMAEXCEPTION_INIT(e1,-1858);BEGINDBMS_OUTPUT.put_line(TO_DATE('13-DEC-20046:56PM','DD-MON-YYYYHH:MI:SS'));END;EXCEPTIONWHENe1THENDBMS_OUTPUT.put_line('Trapped!');END;ORA-06550:第2行,第4列:PLS-00700:'E1'的PRAGMAEXCEPTION_INIT必须在同一个声明部分中的异常错误声明之后ORA-06550:第5行,第7列:PL/SQL:ItemignoredSQL>

结果有出入，设置语言为英文后重跑

SQL>altersessionsetnls_language='american';SessionalteredSQL>SQL>DECLARE2e1EXCEPTION;3PRAGMAEXCEPTION_INIT(e1,-1858);4BEGIN5DBMS_OUTPUT.put_line(6TO_DATE('13-DEC-20046:56PM'7,'DD-MON-YYYYHH:MI:SS'));8EXCEPTION9WHENe110THEN11DBMS_OUTPUT.put_line('Trapped!');12END;13/Trapped!PL/SQLproceduresuccessfullycompletedSQL>

SQL>altersessionsetnls_language='american';SessionalteredSQL>SQL>SQL>DECLARE2e1EXCEPTION;3PRAGMAEXCEPTION_INIT(e1,-1858);4BEGIN5DECLARE6e2EXCEPTION;7PRAGMAEXCEPTION_INIT(e2,-1858);8BEGIN9DBMS_OUTPUT.put_line(10TO_DATE('13-DEC-20046:56PM'11,'DD-MON-YYYYHH:MI:SS'));12END;13EXCEPTION14WHENe215THEN16DBMS_OUTPUT.put_line('Trapped!');17END;18/DECLAREe1EXCEPTION;PRAGMAEXCEPTION_INIT(e1,-1858);BEGINDECLAREe2EXCEPTION;PRAGMAEXCEPTION_INIT(e2,-1858);BEGINDBMS_OUTPUT.put_line(TO_DATE('13-DEC-20046:56PM','DD-MON-YYYYHH:MI:SS'));END;EXCEPTIONWHENe2THENDBMS_OUTPUT.put_line('Trapped!');END;ORA-06550:line14,column9:PLS-00201:identifier'E2'mustbedeclaredORA-06550:line0,column0:PL/SQL:CompilationunitanalysisterminatedSQL>

SQL>altersessionsetnls_language='american';SessionalteredSQL>SQL>SQL>DECLARE2e1EXCEPTION;3BEGIN4DECLARE5PRAGMAEXCEPTION_INIT(e1,-1858);6BEGIN7DBMS_OUTPUT.put_line(8TO_DATE('13-DEC-20046:56PM'9,'DD-MON-YYYYHH:MI:SS'));10END;11EXCEPTION12WHENe113THEN14DBMS_OUTPUT.put_line('Trapped!');15END;16/DECLAREe1EXCEPTION;BEGINDECLAREPRAGMAEXCEPTION_INIT(e1,-1858);BEGINDBMS_OUTPUT.put_line(TO_DATE('13-DEC-20046:56PM','DD-MON-YYYYHH:MI:SS'));END;EXCEPTIONWHENe1THENDBMS_OUTPUT.put_line('Trapped!');END;ORA-06550:line2,column4:PLS-00700:PRAGMAEXCEPTION_INITofE1mustfollowdeclarationofitsexceptioninthesamedeclarativepartORA-06550:line5,column7:PL/SQL:ItemignoredSQL>

答案AB（设置语言为英文，则答案AB；如语言为中文，答案均不正确）

答案说明74楼

A:正确捕获-1858异常B:内层也定义了-1858但是没有捕获，所以外层仍然能够捕获到C:内层的定义在外层是不可见的，会报PLS-00201:identifier'E2'mustbedeclaredD:PRAGMAEXCEPTION_INIT必须和EXCEPTION定义在同一层DECLARE中:PLS-00700:PRAGMAEXCEPTION_INITofE1mustfollowdeclarationofitsexceptioninthesamedeclarativepart