在lazarus中使用加密sqlite3数据库

sqlite3是跨平台开源数据库，运行快捷，使用简单，只一个dll、so即可驱动。

国产信创操作系统中默认安装了驱动。但没有加密功能。

从网上下载sqlite3的加密C脚本，自行编译for win\linux arm驱动。

注意：

1、linux和win对文件夹的要求有异同；

2、sqlite默认不打开外键，必须手动打开。

unit MainDMunit;

{$mode ObjFPC}{$H+}

interface

uses
Classes, SysUtils, Controls, ZConnection, ZDataset,Forms;

type

{ TMainDM }

TMainDM = class(TDataModule)
ImageList1: TImageList;
ImageList2: TImageList;
ImageList3: TImageList;
ZConnect: TZConnection;
ZQTyUserdw: TZQuery;
ZQUserdw: TZQuery;
ZQBalance: TZQuery;
procedure DataModuleCreate(Sender: TObject);
private

public

end;

var
MainDM: TMainDM;

implementation

{$R *.lfm}

{ TMainDM }
uses ZDbcSqLite;

procedure RekeyDB(conn: TZConnection; pwd: string);
var
   db: Pointer;
   i: integer;
begin
if not conn.Connected Then conn.Connect;
db := (conn.DbcConnection as IZSQLiteConnection).GetConnectionHandle;
i := (conn.DbcConnection as IZSQLiteConnection).GetPlainDriver.ReKey
(db, PChar(pwd), Length(pwd));
If (i <> 0) then // 函数正常执行返回0，否则
begin
;
end;
end;
function IsSQLite3File(const FileName: TFileName): boolean;
var F: THandle;
Header:array [0..15] of char ;
begin
F := FileOpen(FileName,fmOpenRead or fmShareDenyNone);
if F= THandle(-1) then
result := false else begin
FileRead(F,Header,15);
if Header='SQLite format 3' then
result:=true
else
result := false;
FileClose(F);
end;
end;

procedure TMainDM.DataModuleCreate(Sender: TObject);
begin
ZConnect.Disconnect;
ZConnect.Protocol:='sqlite-3';
ZConnect.ClientCodepage:='UTF-8';
//linux打开数据库和库用绝对路径，否则创建桌面快捷方式将不能连接数据库
//win用相对路径，否则无法在中文文件夹中打开数据库
{$ifdef linux}
ZConnect.LibraryLocation:= ExtractFilePath(Application.ExeName)+'libsqlite3.so' ;
{$endif}
{$ifdef windows}
ZConnect.LibraryLocation:='sqlite3mc.dll'; //在win下运行时必须改为相当路径
{$endif}
ZConnect.Properties.Clear;
ZConnect.Properties.Add('encrypted=yes');
//ZConnect.Properties.Add('ClientCodepage=UTF-8');
ZConnect.Properties.Add('controls_cp=CP_UTF8');
ZConnect.Properties.Add('AutoEncodeStrings=True');

{$ifdef windows}
ZConnect.Database:='test.db'; //在win下运行时必须改为相当路径
{$else}
ZConnect.Database:= ExtractFilePath(Application.ExeName)+'test.db';
{$endif}
if IsSQLite3File('test.db') then
RekeyDB(ZConnect,'123123') //未加密，则设置数据库密码
else
begin
ZConnect.Password:='123123';//已加密
ZConnect.connect;
end;
ZConnect.ExecuteDirect('PRAGMA foreign_keys=ON'); //必须明确调用才能打开外键

end;
end;

end.