Talk:Lazarus Database Overview
Splitting up so more organized?
This page used to be a tutorial but has changed to become an overview page of various databases and access mechanisms. I propose moving the database specific part out to their own pages (e.g. MySQL) and moving general SQLDB tutorials (e.g. the mysql code-driven example) to a new SQLDB tutorial page, but stripped of db specifics as far as possible (see SQLDB Tutorial1 for an example).
Whatever remains will be perhaps a list of supported databases which can be merged with similar lists for FPC... --BigChimp 06:26, 22 May 2012 (UTC)
Suggestions from 2005 - can these be removed?
Is this still relevant or does this need to be removed? --BigChimp 11:21, 8 August 2011 (CEST)
I would like to change some code given in the MySQL example for Lazarus. I think there are some fundamental errors here. For instance
procedure ShowString (S : string); (* display a string in a Memo box *) begin trymysqlForm1.ResultsMemo.Lines.Add (S) end;
should be done in a methode of the form like:
procedure TtrymysqlForm1.ShowString (S : string); (* display a string in a Memo box *) begin ResultsMemo.Lines.Add (S) end;
It makes the use of the trymysqlForm1 variable obsolete, which might be the cause of runtime errors. Well to cut a long story short, I would like the code to be changed into:
procedure TFormTryMySQL.QueryButtonClick(Sender: TObject); var tableBuffer: PMYSQL_RES; recordBuffer: TMYSQL_ROW; fieldList: TStringList; I: Integer; stMessage: String; begin // Show how we can get records from a table StatusBar1.SimpleText := 'Executing query: ' + CommandEdit.Text; ShowString('Executing query: ' + CommandEdit.Text); if (mysql_query(mySQLSock, PChar(CommandEdit.Text)) < 0) then begin ShowString('Query failed '+ StrPas(mysql_error(mySQLSock))); end else begin tableBuffer := mysql_store_result(mySQLSock); try if tableBuffer = nil then begin ShowString('Query didnot return any results.'); end else begin fieldList := TStringList.Create; try ShowString('Number of records returned : ' + IntToStr(mysql_num_rows(tableBuffer))); ShowString('Number of fields per record : ' + IntToStr(mysql_num_fields(tableBuffer))); // Lets get a list a returned fields. for I := 0 to pred(mysql_num_fields(tableBuffer)) do begin fieldList.Add(mysql_fetch_field_direct(tableBuffer, I).name); end; recordBuffer := mysql_fetch_row(tableBuffer); while (recordBuffer <> nil) do begin stMessage := ; for I := 0 to pred(mysql_num_fields(tableBuffer)) do begin stMessage := stMessage + fieldList[I] + ': ' + recordBuffer[I] + ', '; end; Delete(stMessage, Length(stMessage) - 2, 2); ShowString(stMessage); recordBuffer := mysql_fetch_row(tableBuffer); end; finally fieldList.Free; end; end; finally // Free the results, thus saving resources. mysql_free_result(tableBuffer); end; end; end;
There are some more changes, in fact I expanded it with a second form to show data in a ListView. So if there is any interest in that I'm willing to contribute it to the documentation project.
This page has been converted from the epikwiki version.