请教高手：Oracle中ADO查询记录是否存在的问题

[windwye]

.......
char strSQL[1024];strSQL[0] = '\0';
sprintf((char*)strSQL, "select count(*) as rs_count from tiffimage");
pRecordSetPtr->PutActiveConnection(_variant_t((IDispatch *)theApp.m_pConnection,true));
_variant_t vtNULL;
vtNULL.vt=VT_ERROR;
vtNULL.scode=DISP_E_PARAMNOTFOUND;
pRecordSetPtr->Open(strSQL,vtNULL,adOpenDynamic,adLockPessimistic,adCmdText);
long tmpCount=0;
tmpCount = pRecordSetPtr->GetCollect("rs_count").lVal;
....
sprintf((char*)strSQL, "select * from tiffimage");
pRecordSetPtr->Open(strSQL,vtNULL,adOpenDynamic,adLockPessimistic,adCmdText);
long lRecordCount = pRecordSetPtr->GetRecordCount();

....
结果:
tmpCount =8;
lRecordCount =-1;

为什么lRecordCount不等于8呢？？好像总等于－1；
ADO怎么查询某个字段为某条件的记录是否存在？
我试过用select count(*) as rs_count from (select * from tiffimage where id=56434；得到rs_count 的值与实际相符，但这样也太麻烦了吧？
GetRecordCount返回的是什么东西？

[armu80830]

要将ado的游标类型设置为：客户端游标

[beckhambobo]

http://expert.csdn.net/Expert/topic/2243/2243810.xml?temp=.5211756