Qt - QSql無法獲取行，試圖插入沒有查詢

Question

我試圖插入數據到表中。下面的代碼：

void AddContacts::saveContact() { 

    QString first_name = ui->lineFirstName->text(); 
    QString last_name = ui->lineLastName->text(); 
    QString street_address = ui->lineStreetAddress->text(); 
    QString city = ui->lineCity->text(); 
    QString state = ui->comboBoxState->currentText(); 
    QString zip_code = ui->lineZip->text(); 
    QString personal_email = ui->linePersonalEmail->text(); 
    QString work_email = ui->lineWorkEmail->text(); 
    QString home_phone = ui->lineHomePhone->text(); 
    QString cellular_phone = ui->lineCellularPhone->text(); 
    QString work_phone = ui->lineWorkPhone->text(); 
    QString pager = ui->linePager->text(); 
    QString facebook = ui->lineFacebook->text(); 
    QString twitter = ui->lineTwitter->text(); 
    QString notes = ui->textEditNotes->toPlainText(); 

    // Insert into the database 
    QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE"); 
    db.setDatabaseName("db.db3"); 
    db.open(); 

    QSqlQuery qry; 
    QString query = "INSERT INTO (id, first_name, last_name, street_address, city, state, zip_code, personal_email, work_email, home_phone, cellular_phone, work_phone, pager, facebook, twitter, notes) VALUES('null','" + first_name + "','" + last_name +"','" + street_address + "','" + city + "','" + state + "','" + zip_code + "','" + personal_email + "','" + work_email + "','" + home_phone + "','" + cellular_phone + "','" + work_phone + "','" + pager + "','" + facebook + "','" + twitter + "', '" + notes + "')"; 
    qry.prepare(query); 

    if(!qry.exec()) { 
     qDebug() << qry.lastError(); 
    } 
    else { 
     qDebug() << "Success!"; 
    } 

這裏是我用來創建表：

CREATE TABLE contacts (
id int primary key, 
first_name varchar(20), 
last_name varchar(20), 
street_address text, 
city varchar(30), 
state varchar(20), 
zip_code varchar(10), 
personal_email varchar(40), 
work_email varchar(40), 
home_phone varchar(12), 
cellular_phone varchar(12), 
work_phone varchar(12), 
pager varchar(12), 
facebook text, 
twitter varchar(20), 
notes text); 

我得到這個錯誤：

QSqlError(-1, "Unable to fetch row", "No query")

我不知道我能做錯了。你能找到什麼嗎？

Answer 1

請勿插入字符串'null'作爲列id的值。改爲使用有效的整數。如果你真的想要第一行有一個NULL id，那麼SQL語句看起來像這樣... VALUES (NULL, ...。

您的代碼很容易出錯，因爲您不會在輸入中轉義撇號。如果某些文本字段包含'，則您的SQL語句將失敗。你應該將你的列綁定到變量。這是從Qt參考，你應該使用這種方法：

QSqlQuery query; 
query.prepare("INSERT INTO contacts (id, first_name, last_name) " 
       "VALUES (:id, :first_name, :last_name)"); 
query.bindValue(":id", 1001); 
query.bindValue(":first_name", first_name); 
query.bindValue(":last_name", last_name); 
query.exec(); 

Answer 2

嗨，朋友，我認爲你想念你的表名在查詢。

QString query = "INSERT INTO ??? (id, first_name, last_name, street_address, city, state, zip_code, personal_email, work_email, home_phone, cellular_phone, work_phone, pager, facebook, twitter, notes) VALUES('null','" + first_name + "','" + last_name +"','" + street_address + "','" + city + "','" + state + "','" + zip_code + "','" + personal_email + "','" + work_email + "','" + home_phone + "','" + cellular_phone + "','" + work_phone + "','" + pager + "','" + facebook + "','" + twitter + "', '" + notes + "')"; 
qry.prepare(query); 

我把問號在那個地方