Hi,
On Mon, Nov 16, 2015 at 2:20 PM, R Smith <rsmith at rsweb.co.za> wrote:
>
>
> On 2015/11/16 7:59 PM, Igor Korot wrote:
>>
>> Stephan,
>>
>> On Mon, Nov 16, 2015 at 12:42 PM, Stephan Beal <sgbeal at googlemail.com>
>> wrote:
>>>
>>> On Mon, Nov 16, 2015 at 6:11 PM, Igor Korot <ikorot01 at gmail.com> wrote:
>>>
>>>> The variables referenced are defined as "std::string" and the code is in
>>>> C++.
>>>>
>>> the std::string(char const *) constructor does not, last time i checked,
>>> accept a NULL value. You will need to pass it "" in that case.
>>>
>>> [stephan at host:~/tmp]$ cat foo.cpp
>>> #include <string>
>>>
>>> int main(){
>>> std::string s(0);
>>> return 0;
>>> }
>>>
>>> [stephan at host:~/tmp]$ gcc -o foo foo.cpp -lstdc++
>>> [stephan at host:~/tmp]$ ./foo
>>> terminate called after throwing an instance of 'std::logic_error'
>>> what(): basic_string::_S_construct null not valid
>>> Aborted
>>
>> OK, it looks like the value is NULL instead of "".
>> I will change the code accordingly.
>>
>> BTW, are only name, type and pk fields are guaranteed to have a value?
>
>
> Nothing is guaranteed to have a value unless created with NOT NULL in the
> field specification in the CREATE TABLE schema SQL.
>
> Usually (in most DBs) a Primary key is guaranteed to not have NULL values,
> but in SQLite it is permissible if the PK is not specifically stated to be
> NOT NULL.
Yes.
But if I issue this PRAGMA command the field name, field type and the PK
are guaranteed to have some values, right?
You can't create a field without a name or the type and the field is either part
of the PK or not.
Please correct me if I'm wrong.
Thank you.
>
>
>
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