創建註冊界面以後,數據庫設置了主鍵,當註冊同名用戶時,就會發生寫入數據庫失敗狀況!
我想在第二次寫入數據庫時進行判斷,可又不知道該怎麼寫,讀取後該怎麼寫判斷呢??這種
方法可行嗎?有沒有更簡便的方法呢?求高手指點。。。
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