这篇文章主要介绍“怎么理解数据库集合元素的删除”，在日常操作中，相信很多人在怎么理解数据库集合元素的删除问题上存在疑惑，小编查阅了各式资料，整理出简单好用的操作方法，希望对大家解答”怎么理解数据库集合元素的删除”的疑惑有所帮助！接下来，请跟着小编一起来学习吧！

我创建了一个嵌套表类型和过程：

CREATEORREPLACETYPEplch_numbers_tISTABLEOFNUMBER;/CREATEORREPLACEPROCEDUREplch_show_numbers(title_inINVARCHAR2,numbers_inINplch_numbers_t)ISBEGINDBMS_OUTPUT.put_line(title_in);FORrecIN(SELECTCOLUMN_VALUEFROMTABLE(numbers_in))LOOPDBMS_OUTPUT.put_line(rec.COLUMN_VALUE);ENDLOOP;END;/

下面的选项用来代替下列代码块的 /*BODY*/ 注释:

DECLAREl_numbersplch_numbers_t:=plch_numbers_t(12,23,34,45,56,67,78,89,90,100);BEGIN/*BODY*/plch_show_numbers('AFTERDELETE',l_numbers);END;/

哪些选项使得这个块执行之后会显示如下文本：

AFTERDELETE23456789

换而言之，所有偶数元素都被删除了。

(A)

FORindxIN1..l_numbers.COUNTLOOPIFMOD(indx,2)=0THENl_numbers.delete(indx);ENDIF;ENDLOOP;

SQL>DECLARE2l_numbersplch_numbers_t:=plch_numbers_t(12,323,434,545,656,767,878,989,1090,11100);12BEGIN13FORindxIN1..l_numbers.COUNTLOOP14IFMOD(indx,2)=0THEN15l_numbers.delete(indx);16ENDIF;17ENDLOOP;1819plch_show_numbers('AFTERDELETE',l_numbers);20END;21/AFTERDELETE1234567890PL/SQLproceduresuccessfullycompletedSQL>

(B)

FORindxIN1..l_numbers.COUNTLOOPIFMOD(l_numbers(indx),2)=0THENl_numbers.delete(indx);ENDIF;ENDLOOP;

SQL>DECLARE2l_numbersplch_numbers_t:=plch_numbers_t(12,323,434,545,656,767,878,989,1090,11100);12BEGIN13FORindxIN1..l_numbers.COUNTLOOP14IFMOD(l_numbers(indx),2)=0THEN15l_numbers.delete(indx);16ENDIF;17ENDLOOP;1819plch_show_numbers('AFTERDELETE',l_numbers);20END;21/AFTERDELETE23456789PL/SQLproceduresuccessfullycompletedSQL>

(C)

DELETEFROMTABLE(l_numbers)WHEREMOD(index_value,2)=0;

SQL>DECLARE2l_numbersplch_numbers_t:=plch_numbers_t(12,323,434,545,656,767,878,989,1090,11100);12BEGIN13DELETEFROMTABLE(l_numbers)WHEREMOD(index_value,2)=0;1415plch_show_numbers('AFTERDELETE',l_numbers);16END;17/DECLAREl_numbersplch_numbers_t:=plch_numbers_t(12,23,34,45,56,67,78,89,90,100);BEGINDELETEFROMTABLE(l_numbers)WHEREMOD(index_value,2)=0;plch_show_numbers('AFTERDELETE',l_numbers);END;ORA-06550:第13行,第15列:PL/SQL:ORA-00903:表名无效ORA-06550:第13行,第3列:PL/SQL:SQLStatementignoredSQL>

(D)

FORrecIN(SELECT*FROMTABLE(l_numbers)WHEREMOD(COLUMN_VALUE,2)=0)LOOPl_numbers.delete(rec.COLUMN_VALUE);ENDLOOP;

SQL>DECLARE2l_numbersplch_numbers_t:=plch_numbers_t(12,323,434,545,656,767,878,989,1090,11100);12BEGIN13FORrecIN(SELECT*FROMTABLE(l_numbers)WHEREMOD(COLUMN_VALUE,2)=0)LOOP14l_numbers.delete(rec.COLUMN_VALUE);15ENDLOOP;1617plch_show_numbers('AFTERDELETE',l_numbers);18END;19/AFTERDELETE122334455667788990100PL/SQLproceduresuccessfullycompletedSQL>

实测答案为B

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