SQLite实现加密

SQLite3 4 Delphi：Delphi中操作SQLite库。项目主页：http://code.google.com/p/sv-utils/最新库下载：http://sv-utils.googlecode.com/files/SQLite3_4_Delphi_RC2.zip

wxsqlite：这是wxWidgets组件之一，我们用它来实现加密。下载地址： http://jaist.dl.sourceforge.net/project/wxcode/Components/wxSQLite3/wxsqlite3-3.0.3.zip

下载完上述两个文件后，分别取两个文件中的部分文件：

1，SQLite3 4 Delphi：取“SQLite\sv-utils\SQLite3\Source”目录下3个文件：“SQLite3.pas”、“SQLiteTable3.pas”、“sv.inc”，放到工程里，并     把“SQLite3.pas”、“SQLiteTable3.pas”这两个文件添加到工程里，在使用地方引入这两个单元。

2，wxsqlite：取“wxsqlite3-3.0.3\sqlite3\secure\aes128\dll\release”下的“sqlite3.dll”，放到程序运行目录中。

上面文件准备完毕后，就已经完成对数据库加密需要的全部文件了。

演示代码：

unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants,
  System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls;

type
  TForm2 = class(TForm)
    logMemo: TMemo;
    clearLogBtn: TButton;
    Button2: TButton;
    dbNameEdt: TEdit;
    Label1: TLabel;
    passwordEdt: TEdit;
    Label2: TLabel;
    createTableBtn: TButton;
    insertDataBtn: TButton;
    deleteDataBtn: TButton;
    selectDataBtn: TButton;
    procedure clearLogBtnClick(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure createTableBtnClick(Sender: TObject);
    procedure insertDataBtnClick(Sender: TObject);
    procedure selectDataBtnClick(Sender: TObject);
    procedure deleteDataBtnClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
    procedure MyLog(tempLog: string); // log方法
  end;

var
  Form2: TForm2;

  logInfo: string; // log信息

implementation

{$R *.dfm}

uses SQLite3, SQLiteTable3;

procedure TForm2.Button2Click(Sender: TObject);
var
  sldb: TSQLiteDatabase;
  sltb: TSQLiteTable;
  sSQL: String;
  dbName: string; // 数据库名
  password: string; // 密码
begin

  dbName := trim(dbNameEdt.Text);
  password := trim(passwordEdt.Text);

  try
    sltb := nil;
    sldb := TSQLiteDatabase.Create(dbName, seUTF8, password);
    sldb.ChangePassword(password);

    MyLog('加密数据库创建完毕:数据库 = ' + dbName + ' ; 密码 = ' + password);

  finally
    sldb.Free;
    if sltb <> nil then
    begin
      sltb.Free;
    end;
  end;

end;

procedure TForm2.clearLogBtnClick(Sender: TObject);
begin
  logMemo.Clear;
end;

// 创建表
procedure TForm2.createTableBtnClick(Sender: TObject);
var
  sldb: TSQLiteDatabase;
  sltb: TSQLiteTable;
  sSQL: String;
  dbName: string; // 数据库名
  password: string; // 密码
begin

  dbName := trim(dbNameEdt.Text);
  password := trim(passwordEdt.Text);

  try
    sltb := nil;
    sldb := TSQLiteDatabase.Create(dbName, seUTF8, password);
    sldb.ChangePassword(password);

    sSQL := 'CREATE TABLE IF NOT EXISTS [test] (';
    sSQL := sSQL + '[a] VARCHAR(100)  NULL,';
    sSQL := sSQL + '[b] VARCHAR(100)  NULL';
    sSQL := sSQL + ')';

    sldb.ExecSQL(sSQL);

    MyLog('创建表: test');

  finally
    sldb.Free;
    if sltb <> nil then
    begin
      sltb.Free;
    end;
  end;
end;

procedure TForm2.deleteDataBtnClick(Sender: TObject);
var
  sldb: TSQLiteDatabase;
  sltb: TSQLiteTable;
  sSQL: String;
  dbName: string; // 数据库名
  password: string; // 密码
begin

  dbName := trim(dbNameEdt.Text);
  password := trim(passwordEdt.Text);

  try
    sltb := nil;
    sldb := TSQLiteDatabase.Create(dbName, seUTF8, password);
    sldb.ChangePassword(password);

    sSQL := 'DELETE FROM [test] ';
    sldb.ExecSQL(sSQL);

    MyLog('删除数据完毕 ');

  finally
    sldb.Free;
    if sltb <> nil then
    begin
      sltb.Free;
    end;
  end;
end;

// 添加数据
procedure TForm2.insertDataBtnClick(Sender: TObject);
var
  sldb: TSQLiteDatabase;
  sltb: TSQLiteTable;
  sSQL: String;
  dbName: string; // 数据库名
  password: string; // 密码
  i: integer;
  maxCount: integer; // 添加数据最大数量
begin

  dbName := trim(dbNameEdt.Text);
  password := trim(passwordEdt.Text);

  try
    sltb := nil;
    sldb := TSQLiteDatabase.Create(dbName, seUTF8, password);
    sldb.ChangePassword(password);

    maxCount := 9;

    for i := 0 to maxCount do
    begin
      sSQL := 'INSERT INTO [test] VALUES (';
      sSQL := sSQL + QuotedStr('a' + inttostr(i)) + ',';
      sSQL := sSQL + QuotedStr('b' + inttostr(i));
      sSQL := sSQL + ')';

      sldb.ExecSQL(sSQL);
    end;

    MyLog('共添加: ' + inttostr(maxCount + 1) + ' 条数据');

  finally
    sldb.Free;
    if sltb <> nil then
    begin
      sltb.Free;
    end;
  end;
end;

// log方法
procedure TForm2.MyLog(tempLog: string);
var
  temp: string;
  oldLog: string;
begin
  if trim(tempLog) <> '' then
  begin

    oldLog := trim(logMemo.Text);
    logMemo.Clear;

    temp := FormatDateTime('yyyy-mm-dd hh:mm:ss', now) + ' ' + trim(tempLog);
    if oldLog = '' then
    begin
      logMemo.Lines.Add(temp);
      logMemo.Lines.Add('');
    end
    else
    begin
      logMemo.Lines.Add(temp);
      logMemo.Lines.Add('');
      logMemo.Lines.Add(oldLog);
    end;

  end;

end;

procedure TForm2.selectDataBtnClick(Sender: TObject);
var
  sldb: TSQLiteDatabase;
  sltb: TSQLiteTable;
  sSQL: String;
  dbName: string; // 数据库名
  password: string; // 密码
  totalCount: integer;
  temp: string;
begin

  dbName := trim(dbNameEdt.Text);
  password := trim(passwordEdt.Text);

  try
    sltb := nil;
    sldb := TSQLiteDatabase.Create(dbName, seUTF8, password);
    sldb.ChangePassword(password);

    sSQL := 'SELECT * FROM [test] ';
    sltb := sldb.GetTable(sSQL);

    // 1，显示总数据条数

    totalCount := 0;
    if not sltb.EOF then
    begin
      totalCount := sltb.Count;
    end;

    MyLog('共: ' + inttostr(totalCount) + ' 条数据');

    // 2，显示详细信息

    temp := '';

    while not sltb.EOF do
    begin

      if temp = '' then
      begin
        temp := #13#10 + sltb.FieldValByNameAsString['a'] + ' ; ' +
          sltb.FieldValByNameAsString['b'] + #13#10;
      end
      else
      begin
        temp := temp + sltb.FieldValByNameAsString['a'] + ' ; ' +
          sltb.FieldValByNameAsString['b'] + #13#10;
      end;

      sltb.Next;
    end;

    if temp <> '' then
    begin
      MyLog('详细数据：' + #13#10 + temp);
    end;

  finally
    sldb.Free;
    if sltb <> nil then
    begin
      sltb.Free;
    end;
  end;
end;

end.