Delphi：SQLite和UniDac

Question

需要在SQLite中存储一些数据。使用SQLite选择了UniDac，但是有一个问题：当在UniConnection中，在“数据库”字段中，我选择SQLite并输入数据库的名称 - 得到错误“不支持的元数据类型”。未创建数据库文件。问题是什么？正如之前与UniDac合作过的那样，没有观察到这些问题。

Answer 1

UniDAC 4.1.6与Delphi XE2我没有看到任何问题。 SQLite3.dll必须位于系统路径或与可执行文件相同的目录中。下面的基本示例在单击btnConnect时创建数据文件。

unit uMain;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.Grids, Vcl.DBGrids, UniProvider,
  SQLiteUniProvider, Data.DB, MemDS, DBAccess, Uni, Vcl.ExtCtrls, Vcl.DBCtrls,
  Vcl.StdCtrls;

type
  TfrmMain = class(TForm)
    UniDataSource1: TUniDataSource;
    UniConnection1: TUniConnection;
    UniQuery1: TUniQuery;
    SQLiteUniProvider1: TSQLiteUniProvider;
    DBGrid1: TDBGrid;
    edtDBName: TEdit;
    Label1: TLabel;
    DBNavigator1: TDBNavigator;
    btnConnect: TButton;
    procedure btnConnectClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  frmMain: TfrmMain;

implementation

{$R *.dfm}

procedure TfrmMain.btnConnectClick(Sender: TObject);
begin
  if (btnConnect.Caption = 'Connect') then
  begin
    UniConnection1.ProviderName := 'SQLite';
    UniConnection1.Database := ExtractFilePath(Application.ExeName)
     + edtDBName.Text;
    UniConnection1.Connect;
    btnConnect.Caption := 'Disconnect';
  end
  else
  begin
    UniConnection1.Disconnect;
    btnConnect.Caption := 'Connect';
  end;
end;