如何檢查用戶是否已經在我的Web應用程序中使用Google + API登錄？

Question

我正嘗試在我的web應用程序中使用Google + API &登錄。我是否需要在登錄時存儲數據並在每次登錄時檢查數據庫？

Answer 1

Yes,Add authprovider field in your table. 
When any user login with google at first time then store google in your database. 
After than when user Login again then use query like this: 

$query = "SELECT authprovider,email FROM tbl_users WHERE authprovider='$authprovider' AND email='$email'"; 
$exe = mysqli_query($conn,$query); 
$check = mysqli_num_rows($exe); 
if($check == 1){ 
    //already registered 
} 
else{ 
//new register 
}