Re: mysql , gnade and function hanging

[Ludovic Brenta <ludovic@ludovic-brenta.org>]

tonyg wrote on comp.lang.ada:
> I've sanistised this source of the password and ip address
>
> with GNU.DB.MySQL;
> with GNU.DB;
> use GNU.DB.MySQL;
> use GNU.DB;
> with Ada.Text_Io; use Ada.Text_Io;
> with Ada.Strings.Unbounded;
> use Ada.Strings.Unbounded;
>
> procedure trymysql is
>
> TheDatabase : MySQL.Object;
> TheQuery    : MySQL.Query_Id;
> TheField        : MYSQL.Field_Number;
> begin
> Initialize(TheDatabase);
> User (TheDatabase, "heating");
> Password (TheDatabase,"");
> Connect (TheDatabase,"");
> Select_DB (TheDatabase, "heating");
>
>    TheQuery := Query (TheDatabase, "select * from userid ");
>    TheField := Get_Field_Number (TheDatabase, TheQuery, "email");
>
>    put_line ("Number of Rows :" &
> Integer'Image(Nbr_of_Rows(TheDatabase,TheQuery)));
>
>         put_line (" Field Number of Email field : " &
> Integer'Image(TheField));
>
>     Put_Line(Natural'image (Get_Field_Length(TheDatabase,TheQuery,
> 1)));
>     Put_Line(Field_Type'image(Get_Field_Type(TheDatabase,TheQuery,
> 1)));
>
>     Put_Line(To_String(String_Field (TheDatabase, TheQuery,
> "email")));
> end trymysql;
>
> Out put is
>
> tony@tony-laptop:~/snugbug/main/adastuff/heating/src$ ./trymysql
> Number of Rows : 4
>  Field Number of Email field :  1
>  14
>
> raised CONSTRAINT_ERROR : gnu-db-mysql.adb:883 invalid data
> tony@tony-laptop:~/snugbug/main/adastuff/heating/src$
>
> Other information is that the email field in the database table is a
> VARCHAR(80) and a primary key

It seems the exception is not raised in the String_Field line as you
initially said, but in the previous line that calls Get_Field_Type
directly (String_Field also calls Get_Field_Type). The exception
message "invalid data" indicates an uninitialized variable. At first I
thought this would be the TheQuery (of type Query_ID) but now I'm not
so sure anymore. I suggest you run this small program in a debugger
and inspect all the parameters passed to Get_Field_Type.

I do not use gnade myself, or MySQL. I no longer maintain gnade in
Debian; Stephe Leake took over and dropped support fro MySQL because
it was out of sync with recent versions of MySQL. So that, in fact,
might be the cause of your problems.

What platform do you use?
What version of gnade?
What version of MySQL?

Maybe you should use the ODBC interface instead; it is more stable
than the MySQL-specific API.

--
Ludovic Brenta.