SQLite Exception raised with message: no such table

问题

I created an application that collects information from the computer (computer name, CPU, Memory, etc) but I am having such a hard time displaying the information stored in the SQLite database, when I execute a query I get the “NO SUCH TABLE” message when I know for sure I have a table called “hardware” what am I doing wrong?

Here the code I use to execute the query:

procedure TMain.executeButtonClick(Sender: TObject);
var
  results: TDataSet;
  query: String;

begin
  outputMemo.ClearSelection;
  query := 'SELECT * FROM hardware;';
  try
    SQLConnection1.Execute(query, nil, results);
  except
    on E: Exception do
      outputMemo.Text := 'Exception raised with message: ' + E.Message;
  end;
  ShowSelectResults(results);
end;

The database file and table are created programmatically created every time the application runs

procedure CheckForDatabase;
var
  sldb: TSQLiteDatabase;
  sSQL: string;

begin
  slDBPath := ExtractFilePath(paramstr(0)) + 'ComputerName.db';
  // ShowMessage(slDBPath);
  sldb := TSQLiteDatabase.Create(slDBPath);
  try
    if sldb.TableExists('hardware') then
      begin
        sSQL := 'DROP TABLE hardware';
        sldb.ExecSQL(sSQL);
      end;

    sSQL := 'CREATE TABLE hardware (id INTEGER PRIMARY KEY, compname TEXT, username TEXT, model TEXT, manufacturer TEXT, domain TEXT, ip TEXT, serialnumber TEXT)';
    sldb.ExecSQL(sSQL);
    sldb.ExecSQL('CREATE INDEX sHardware ON hardware(CompName);');
    sldb.BeginTransaction;
    sSQL := 'INSERT INTO hardware(id, compname, username, model, manufacturer, domain, ip, serialnumber) VALUES (1, "AMD8537", "OMonge", "Gigabyte", "Gigabyte", "Workgroup", "192.168.1.11", "8746652");';
    sldb.ExecSQL(sSQL);
    sldb.Commit;
  finally
    sldb.Free;
  end;
end;

And this is the SQLite database:

Any help you can provide me with will be greatly appreciated. Thank you.

回答1:

You Taged Delphi-XE2 so my answer belongs to XE2

From version RAD Studio XE3 TSQLMonitor supports SQLite databases. ...

With XE2 You can not use SQLConnection1: TSQLConnection; with Driver Sqlite !
Will not work SQLConnection1.Execute(query, nil, results);

According to the code used , it seems to be the simple Delphi wrapper for Sqlite 3 to act.

So you can use the just created sldb .

slDBPath := ExtractFilePath(paramstr(0)) + 'ComputerName.db';
sldb := TSQLiteDatabase.Create(slDBPath);

In the procedure CheckForDatabase;

remove

var
  sldb: TSQLiteDatabase;

and put it to the interface of your Application

private
    { Private declarations }
    sltb: TSQLIteTable;
    sldb: TSQLiteDatabase;

also remove sldb.Free; form the finally block

finally
    sldb.Free;
end;

In your executeButtonClick(...

procedure TMain.executeButtonClick(Sender: TObject);
var
  query: String;

begin
  outputMemo.ClearSelection;
  query := 'SELECT * FROM hardware;';
  sltb := sldb.GetTable(query);
  if sltb.Count > 0 then begin
     //display first row
     ....
  if not sltb.IsLastRow the begin
     sltb.Next;
     //display next row
     ....

how to display field values : look here

来源：https://stackoverflow.com/questions/16585953/sqlite-exception-raised-with-message-no-such-table

标签

Delphi

sqlite

delphi-xe2