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Connect to database
Posted: Fri 08 Jun 2012 06:26
by marsheng
I have my Delphi app all running and now I want to add a login page. Up to now, I've used the Devart login box. I think the way I connect is specific to Devart.
I tried this
Code: Select all
procedure TfLogin.bEnterClick(Sender: TObject);
begin
dm.MyRegister.Username:=eUsername.Text;
dm.MyRegister.Password:=ePassword.Text;
dm.MyRegister.Connect; < ----------------- get error.
if dm.MyRegister.connected then
fmain.ShowModal;
end;
Access denied. Two things, I need to know how to connect and also check if connected.
Alternatively, how do I get the source for the Connection editor ?
Thanks Wallace
Re: Connect to database
Posted: Mon 11 Jun 2012 12:08
by AndreyZ
Hello,
When you try connecting to a MySQL server and MySQL generates an error, the MySQL error message is shown. To change this behaviour, you can write your own connection form. Please take a look at the example of such connection form in the MyDACDemo->ConnectDialog demo. The source code of the TMyConnectForm connection form is supplied with MyDAC (the MyConnectForm.pas unit), so you can change it in the way you need it. You can get more information about the "Access denied" error and the ways to avoid it here:
http://dev.mysql.com/doc/refman/5.1/en/ ... enied.html
Re: Connect to database
Posted: Wed 13 Jun 2012 11:07
by marsheng
-I'm getting TDemoFrame not found in the demo software.
-When I open Delphi, I get a SQL login screen. I want to create my own login. How do I disable the screen so I can create my own?
-What is the main difference between connecting to the sql with MyConnect and MyConnectionDialog?
Favourite saying: It is easy - if you have done it before.
Re: Connect to database
Posted: Thu 14 Jun 2012 08:35
by AndreyZ
To solve this problem, you should open MyDACDemo, click "OK" in the error dialog, and save the project. After this, you will not have this problem.
Please take a look at the example of a custom connection dialog in the MyDACDemo->ConnectDialog demo. It demonstrates how to create a custom connection dialog and use it in the application instead of the default connection dialog.
Re: Connect to database
Posted: Sun 17 Jun 2012 20:57
by marsheng
I seem to have lost a posting. !!!!
I've looked through the demos but can't find what I need.
How do I get the following to connect (no user input required and error trapping excluded)
Message Access denied - It will however login if I use the MyConnectdialog so my parameters are correct.
Code: Select all
procedure TForm1.Button2Click(Sender: TObject);
begin
MyConnection1.LoginPrompt:=false;
MyConnection1.Port:=3306;
MyConnection1.Server:='127.0.0.1';
MyConnection1.Username:='Root';
MyConnection1.Password:='';
MyConnection1.Database:='register';
MyConnection1.Connected:=True; <-------------- Crash
end;
Re: Connect to database
Posted: Sun 17 Jun 2012 21:31
by marsheng
I have to apologise - My mistake, the login name is case sensitive. Root <> root.
Hopefully the last problem, What is the syntax for error handling?
Code: Select all
try
MyConnection1.Connected:=True;
except
???
end;
Even using MyConnectDiaglog, Delphi crashes when a parameter is incorrect.
Re: Connect to database
Posted: Mon 18 Jun 2012 08:26
by AndreyZ
If you use a connection dialog, you can handle connection errors in the OnError event handler of the TMyConnection component. Here is a code example:
Code: Select all
procedure TMainForm.MyConnectionError(Sender: TObject; E: EDAError;
var Fail: Boolean);
begin
ShowMessage('Error code: ' + IntToStr(E.ErrorCode));
end;
For more information about the OnError event handler, please refer to the MyDAC documentation.
Re: Connect to database
Posted: Sat 23 Jun 2012 10:16
by marsheng
I'm going round in circles.
MyConnection has a parameter called Connected.
How do I trap the errors when implementing it?
Code: Select all
try
MyConnection1.Connected:=True;
except
???
end;
The connectdialog does not give me what I want.
Re: Connect to database
Posted: Sat 23 Jun 2012 12:10
by AlexP
Hello,
To process errors occuring when working with MyDAC, you can use the EMyError class, for example:
Code: Select all
uses ...., MyClasses;
...
try
MyConnection1.Connected:=True;
except
on E: EMyError do
ShowMessage(Format('Error Code: %d, Error Message: %s',[e.ErrorCode, E.Message]));
end;
Re: Connect to database
Posted: Sun 24 Jun 2012 00:33
by marsheng
Thanks, That is what I was looking for
Now it works.
Re: Connect to database
Posted: Sun 24 Jun 2012 11:15
by marsheng
This seems to work
Code: Select all
procedure TfLogin.ConnectClick(Sender: TObject);
begin
MyConnection1.Connected:=False;
MyConnection1.Server:=eServer.Text;
MyConnection1.Port:=StrToInt(ePort.Text);
MyConnection1.Database:=eDataBase.Text;
MyConnection1.Username:=eUsername.Text;
MyConnection1.Password:=ePassword.Text;
try
MyConnection1.Connected:=True;
except
on E: EMyError do begin
if e.ErrorCode = 1045 then
ShowMessage('Invalid Server Address or Password')
else if e.ErrorCode = 1044 then
ShowMessage('Invalid Username or Password')
else if e.ErrorCode = 1049 then
ShowMessage('Trying to Connect to Unknown Database')
else if e.ErrorCode = 2003 then
ShowMessage('Cannot connect to server. Port Error')
else
ShowMessage(Format('Error Code: %d, Error Message: %s',[e.ErrorCode, E.Message]));
end;
else
ShowMessage('Unknown error');
end;
end;
I get my data from here.
Code: Select all
Memo1.Lines.LoadFromFile('config.ini');
eUserName.Text:=Memo1.Lines[3];
ePassword.Text:=Memo1.Lines[4];
eServer.Text:=Memo1.Lines[0];
ePort.Text:=Memo1.Lines[1];
eDataBase.Text:=Memo1.Lines[2];
Finally.
Re: Connect to database
Posted: Tue 26 Jun 2012 13:04
by AlexP
hello,
If you have any other questions, feel free to contact us.
Re: Connect to database
Posted: Tue 03 Jul 2012 11:28
by marsheng
All was going well until I tried to connect from outside my network.
I can connect with localhost or my fixed IP address 101.xx.xx.xx (modem loopback) from within my office network. However when connecting from outside, the package waits for quite some time and then reports a MS crash with connect to 10.0.0.16, which is my internal IP address for the SQL server????
The SQl is up and running and I can connect from outside our office (Using Heidi) to the database and table prefectly so it can't be the routers issue.
I confused where the 10.0.0.16 came from, if the Delphi app could not connect, it would have been an 101.XX.XX.XX error and one of my error messages would have been triggered.
Any suggestions ? Code above.
Re: Connect to database
Posted: Wed 04 Jul 2012 10:03
by AndreyZ
Please make sure you are using exactly the same connection options in the TMyConnection component and Heidi. Especially check that the TMyConnection.Server property is set to the correct IP.
Re: Connect to database
Posted: Wed 04 Jul 2012 10:21
by marsheng
They are all exactly the same. They have to be correct as I can connect locally using my routers fixed IP address.
I copied my DB to My ISP server and ran the same program. It it worked correctly.
I looked at the setting in my router for connection faults but couldn't find any.
While fiddeling around I found the Creation order form on the MyConnection box. I put MyConnection at the top of the list and it fixed it.
Why it worked localy and not on some remote systems I don't know.