oracle – IS OF TYPE生成异常

概述我读了大约 IS OF TYPE,我希望它应该返回TRUE,FALSE或NULL. 我有两种对象类型： CREATE TYPE o1 AS OBJECT ( id NUMBER );/CREATE TYPE o2 AS OBJECT ( id NUMBER );/ 当我运行下面的代码时,一切正常. DECLARE type1 o1;BEGIN type1 := o1(id=>1) 我读了大约 IS OF TYPE,我希望它应该返回TRUE,FALSE或NulL.

我有两种对象类型：

CREATE TYPE o1 AS OBJECT ( ID NUMBER );/CREATE TYPE o2 AS OBJECT ( ID NUMBER );/

当我运行下面的代码时,一切正常.

DECLARE  type1 o1;BEGIN   type1 := o1(ID=>1);    if (type1 IS OF (o1)) then       DBMS_OUTPUT.PUT_liNE('type1 is o1');                       END if;  END;/

但是当我尝试运行时：

DECLARE  type1 o1;BEGIN   type1 := o1(ID=>1);    if (type1 IS OF (o2)) then       DBMS_OUTPUT.PUT_liNE('type1 is o1');                       END if;  END;/

我收到以下例外情况

Error report:ORA-06550: line 6,column 21:PLS-00382: Expression is of wrong typeORA-06550: line 6,column 4:PL/sql: Statement ignored06550. 00000 -  "line %s,column %s:\n%s"*Cause:    Usually a PL/sql compilation error.*Action:

在文档中没有明确的解释,如果某些类型错误,我是否应该捕获异常？或者,我应该在IF条件下假设错误吗？

解决方法 如果您已将变量声明为O1类型,那么您可以使用[type]条件来测试您的变量是o1类型还是o1的子类型.这是一个例子(变量必须实例化)：

-- base type   sql> create or replace type o1 as object(  2    prop number  3  )not final;  4  /Type created-- O1's subtypesql> create or replace type o2 under o1(  2    prop1 number  3  );  4  /-- test if the  l_o1 is of O1 typesql> declare  2    l_o1  o1;  3  begin  4    l_o1 := o1(prop=>1);  5    if l_o1 is of (o1)  6    then  7      dbms_output.put_line('Yes');  8    else  9      dbms_output.put_line('No'); 10    end if; 11  end; 12  /YesPL/sql procedure successfully completed-- test if the  l_o1 is of O2 typesql> declare  2    l_o1  o1;  3  begin  4    l_o1 := o1(prop=>1);  5    if l_o1 is of (o2)  6    then  7      dbms_output.put_line('Yes');  8    else  9      dbms_output.put_line('No'); 10    end if; 11  end; 12  /NoPL/sql procedure successfully completed-- test if the  l_o2 is of O2 typesql> declare  2    l_o2  o2;  3  begin  4    l_o2 := o2(prop=>1,prop1 => 1);  5    if l_o2 is of (o2)  6    then  7      dbms_output.put_line('Yes');  8    else  9      dbms_output.put_line('No'); 10    end if; 11  end; 12  /YesPL/sql procedure successfully completed

更新：

Take a look at this获取有关[type]的更多信息.通常,变量的数据类型在编译时是已知的,但如果您必须处理动态类型,则可以查看anydata(对象数据类型).这是一个简单的例子：

sql> declare  2    l_o1 o1;  3    4    -- Here is a procedure(for the sake of simplicity has not  5    -- been written as a schema object)  6    -- that doesn't not kNow  7    -- variable of what dada type will be passed in  8    -- at compile time;  9    procedure DoSomething(p_var anydata) 10    is 11    begin 12      case p_var.gettypename 13        when 'HR.O1' 14        then dbms_output.put_line('O1 data type. Do something'); 15        when 'HR.O2' 16        then dbms_output.put_line('O2 data type. Do something'); 17      else 18        dbms_output.put_line('UnkNown data type'); 19      end case; 20    end; 21   22  begin 23    l_o1 := o1(prop =>  1); 24    DoSomething(anydata.ConvertObject(l_o1)); 25  end; 26  /O1 data type. Do somethingPL/sql procedure successfully completed

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