Mysql delphi problem ?? Ado ??

Hi, i´m new around here and have this big problem to solve.
The fact is that i´m using Delphi 7 + Ado + MyODBC 3.51 and Mysql 4.1 and someting strange is happening. The code i´m going to write down works perfectly with SQL Server 2000.

The fact is that if i acessed the same ado query previously it gives me the error "acess violation at address 1F45E7E in module 'msado15.dll'. write of address 01134010 ".

let me explain better: If I change the first ADOQuery for another with a different name, like ADOQtest (and put a adoq test on the form), the code works perfectly, but if i let like it is below, gives that error.

procedure TfrmPrincipal.Button3Click(Sender: TObject);
var ultimo:integer;
begin
with ADOQenvelope do
begin
Close;
sql.Clear;
sql.Add('select * from envelope order by enve_id');
Open;
Last;
ultimo:=ADOQenvelope.fieldbyname('enve_id').asinteger+1;
showmessage(inttostr(ultimo));

end;

with ADOQenvelope do
begin
close;
sql.clear;
sql.add('insert into envelope');
sql.add(' (enve_id,usu_id_envelope, enve_regirregulares,enve_reginformados,enve_regdigitalizados)');
sql.add(' values (:cod,:velope,:irreg,:infor,:digitali)');
Parameters.ParamByName('cod').value:=ultimo;
Parameters.ParamByName('velope').Value:=strtoint(EDusuid.text);
Parameters.ParamByName('irreg').Value:=strtoint(Edregirregu.text);
Parameters.ParamByName('infor').Value:=12;
Parameters.ParamByName('digitali').Value:=12;
ExecSQL;
end;
end;

Seems like i can use a query only one time....And every time i try to do a different "action" with a previously used query, it hangs..

Select works fine, but, if i use this adoquery before just to do a select, like above, it gives that error.

Can someone help me?
It´s a Mysql problem? Ado ?

Sounds like a MyODBC problem to me. BTW there are some known issues and workarounds. See
http://dev.mysql.com/doc/mysql/en/P...ith_MyODBC.html

I solved the problem in a very unusual way...

every time i want to insert data in a database, first i use this:

adoconnect.connected:=false; and then
adoconnect.connected:=true;

.... insert into ....

and works... don´t ask me why !!!!

INSTEAD OF disconnecting & connecting every time,

try using a ADOCommand Component instead of ADOQuery. It will work fine.

If you disconnect & connect everytime, the operations will become slow.