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From:Jithin Emmanuel Date:March 20 2009 5:51am
Subject:Re: checking NULL
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I am using version 2 23 and is not in a position to upgrade.
I am not comparing against the string. I am doing

  if(row["name"] == mysqlpp::null) {
                                                cout << " NULL VALUE" <<
endl;
                                }
This is what giving me there error.
est.cpp:58: error: no match for 'operator==' in
'mysqlpp::Row::operator[](const char*) const(((const char*)"name")) ==
mysqlpp::null'

Is it possible to instantiate mysqlpp::NULL with row["name"] and use is_null
parameter? But I cannot make that work also.

On Fri, Mar 20, 2009 at 10:39 AM, Warren Young <mysqlpp@stripped> wrote:

> On Mar 19, 2009, at 10:50 PM, Jithin Emmanuel wrote:
>
>                                name = row["name"].get_string();
>>
>
> First, you really should consider upgrading to MySQL++ v3.  You're clearly
> still on 2.3 or earlier.  There have been probably half a dozen changes to
> the way we handle SQL nulls in v3.0.0 and later, some of them highly useful.
>
> Second, my previous reply didn't say to convert the return value of
> Row::operator[]() to a std::string and then make the test.  I said to test
> the return value of Row::operator[]() directly.  Why?  Because there's
> nothing like SQL null in C or C++.  When you convert SQL data to a non-SQL
> data type, you lose the SQL null flag.  You must test for the flag before
> you make the conversion.
>
>
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>


-- 
Regards
Jithin Emmanuel
http://spotm.in
Samuel Beckett  - "Birth was the death of him."

Thread
checking NULLJithin Emmanuel19 Mar
  • Re: checking NULLWarren Young19 Mar
    • Re: checking NULLJithin Emmanuel19 Mar
      • Re: checking NULLWarren Young19 Mar
        • Re: checking NULLJithin Emmanuel20 Mar
          • Re: checking NULLWarren Young20 Mar
            • Re: checking NULLJithin Emmanuel20 Mar
              • Re: checking NULLJithin Emmanuel20 Mar
              • Re: checking NULLWarren Young20 Mar