Title: Create a Delphi Ado application from Scratch
Question: Sometimes we need to build an ADO application without using delphi ADO components
Answer:
Create a Delphi Ado application from Scratch.
Sometimes we need to build an ADO application without using delphi ADO components. To do that you have to use the Delphi 5 Enterprise. For these cases we made a CookBook to do that:
1) Create a database on MSAcess with one table named clients;
2) Insert four fields in your client table;
3) In the Control Panel, choose the ODBC Data Sources and create a System DSN named Adotest;
4) open Delphi;
5) On a new project, insert a Tbutton and a Tmemo in your form;
6) Insert the ComObj in the uses clausule;
7) In the Onclick event insert this code:
procedure TForm1.Button1Click(Sender: TObject);
var
RecordSet: OleVariant;
temp: string;
DSN: string;
SelectString : string;
i : integer;
begin
// ODBC dsn from ACESS database.
DSN := 'dsn=AdoTest';
// the SQL string
SelectString := 'SELECT * FROM clientes';
// Create an empty recordset object
RecordSet := CreateOleObject('ADODB.Recordset');
// Fill the recordset
RecordSet.Open(SELECTSTRING, DSN);
// Display the data
repeat
// the client table has four fields
// this loop will put one record per line in the memo
for i:= 0 to 3 do
temp := temp + ' ' + RecordSet.Fields[i].Value;
Memo1.Lines.Add(temp);
RecordSet.MoveNext;
temp := '';
until RecordSet.EOF;
end;
These litle application will make a search in a database after you click in the button an than the application will put the results in the Memo. You can use this to build a simple COM component with data acess without using MIDAS, for example.
Thats all folks.
:o)