A m Z o n e

Explicit and implict convertion of datatypes

Oracle implicitly converts datatypes during assignment if not explicitly specified. Which in your opinion should we adhere to when coding, implicit conversion done by oracle or explicitly specified by the developer?

   eg: 
    declare 
      l_chr  varchar2(10); 
      l_num  number(10); 
    begin 
      l_num := 100; 
      l_chr := l_num;              -- implicit conversion (or) 
      l_chr := to_char(l_num);     -- explicit conversion 
      dbms_output.put_line(l_chr); 
      ..... 
    end;  

Oracle's conversion methodology may change over the releases. For example the following is the result of different behaviour in Oracle versions. White space assigned to a number was acceptable in Oracle 7.3, but not so in Oracle 8i.

   eg: 
   declare 
      l_num number; 
   begin 
      l_num := ' '; 
   end; 

   In oracle 7.3.4, the above code returns: 
         PL/SQL procedure successfully completed. 

   In Oracle 8.1.7, the above code returns: 
        ERROR at line 1: 
        ORA-06502: PL/SQL: numeric or value error: character to number conversion error 
        ORA-06512: at line 4 

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