不同机器不重复编号、流水号生成

在添加记录insert前判断是否流水号重复，表中要建立macdizhi字段存储mac地址，参看健鹏软件

设计思路：

01     02      03（机器号）

25     25      25（流水号）

当几台机器获取流水号相同时，要判断数据库中是否有25的流水号

                       判断第一条记录是不是该机器添加的

有记录时----      如果是  ->  流水号不变

                       如不是  ->  选记录数最大流水号，改变当前流水号并赋值

无记录  ---- 直接添加

        //查看流水号，避免不同计算机流水号输入重复，只限单机只开一个客户端
        with    ADOQuery_temp   do
        begin
                Close;
                SQL.Clear;
                SQL.Add('select liushuihao from Y_liushui where liushuihao=:liushuihao and caozuobiaoshi=''药品销售''');
                Parameters.ParamByName('liushuihao').Value:=Trim(Edit_liushuihao.Text);
                Open;
        end;

        if      ADOQuery_temp.RecordCount>0   then
        begin
                //判断记录是不是该机器录的，如果是，流水号不变，如不是要再选出最大流水号并赋值
                with    ADOQuery_temp   do
                begin
                        Close;
                        SQL.Clear;
                        SQL.Add('select liushuihao from Y_liushui where liushuihao=:liushuihao and macdizhi=:macdizhi and caozuobiaoshi=''药品销售''');
                        Parameters.ParamByName('liushuihao').Value:=Trim(Edit_liushuihao.Text);
                        Parameters.ParamByName('macdizhi').Value:=Trim(Frm_Login.GetMacAddress);
                        Open;
                end;
                //如不是自己机器录的，选最大流水号赋值
                if    ADOQuery_temp.RecordCount=0   then
                begin
                      with    ADOQuery_liushuihaocx   do
                      begin
                              Close;
                              SQL.Clear;
                              SQL.Add('select isnull(max(liushuihao),0) as liushuihao from Y_liushui where caozuobiaoshi=''药品销售''');
                              Open;
                      end;
                      if      (ADOQuery_liushuihaocx.FieldValues['liushuihao']=null) or (ADOQuery_liushuihaocx.FieldValues['liushuihao']=0)   then
                      begin
                              Edit_liushuihao.Text:='1';
                      end
                      else
                      begin
                              Edit_liushuihao.Text:=IntToStr(ADOQuery_liushuihaocx.FieldValues['liushuihao']+1);
                      end;
                end;
        end;

//获取计算机Mac地址函数

function TFrm_Login.GetMacAddress: string;
var
   Lib: Cardinal;
   Func: function(GUID: PGUID): Longint; stdcall;
   GUID1, GUID2: TGUID;
begin
   Result := '';
   Lib := LoadLibrary('rpcrt4.dll');
   if Lib <> 0 then
   begin
     if Win32Platform <>VER_PLATFORM_WIN32_NT then
       @Func := GetProcAddress(Lib, 'UuidCreate')
       else @Func := GetProcAddress(Lib, 'UuidCreateSequential');
     if Assigned(Func) then
     begin
       if (Func(@GUID1) = 0) and
         (Func(@GUID2) = 0) and
         (GUID1.D4[2] = GUID2.D4[2]) and
         (GUID1.D4[3] = GUID2.D4[3]) and
         (GUID1.D4[4] = GUID2.D4[4]) and
         (GUID1.D4[5] = GUID2.D4[5]) and
         (GUID1.D4[6] = GUID2.D4[6]) and
         (GUID1.D4[7] = GUID2.D4[7]) then
       begin
         Result :=
          IntToHex(GUID1.D4[2], 2) +'-'+
          IntToHex(GUID1.D4[3], 2) +'-'+
          IntToHex(GUID1.D4[4], 2) +'-'+
          IntToHex(GUID1.D4[5], 2) +'-'+
          IntToHex(GUID1.D4[6], 2) +'-'+
          IntToHex(GUID1.D4[7], 2);
       end;
     end;
     FreeLibrary(Lib);
   end;
end;