php - PDO数据库用户存在控制

Question

if(isset($_GET['id'])){
    $nome = $_GET['nome'];
    $cognome = $_GET['cognome'];
    $id = $_GET['id'];
    $sql = "UPDATE utenti SET nome = :nome, cognome = :cognome WHERE id = :id";
    $req = $dbh->prepare($sql);
    $req->execute(
        array(
            ":nome" => $nome,
            ":cognome" => $cognome,
            ":id" => $id,
            )
        );
} else {
    $nome = $_GET['nome'];
    $cognome = $_GET['cognome'];
    $sql = "INSERT INTO utenti (nome, cognome) VALUES (:nome, :cognome)";
    $req = $dbh->prepare($sql);
    $req->execute(
        array(
            ":nome" => $nome,
            ":cognome" => $cognome,
            )
        );
}

大家好。我有这段代码，可以在数据库中插入或更新表单的数据。我想包括一个“if”检查，以确保您正在检查该用户是否已存在于数据库中。我能怎么做？谢谢

Answer 1

试试这个:

               $nome = $_GET['nome'];
            //Searching the nome in the database
                    $req = $dbh->prepare("SELECT COUNT(*) AS anzahl FROM user WHERE Benutzername = :nome");
            //Counts the rows with the given nom
                    $req->bindParam(':nome', $nome, PDO::PARAM_STR);
                    $req->execute();
                    $result = $req->fetch();
                    if ($result[0] > 0) {
            //already exists - A row was found 
                        echo "Already exists";
                    }
                    else {
            //not existing - There was no row with that username
                     "Your Insertquery, use $req2 here"
                    }

编辑 2:现在应该可以工作了 ^^