java - 使用 Java 将数据插入 mySQL DB 时出错

Question

大家晚安。我有这些代码。我只是将有问题的代码复制到这里。

//This is my main method. I called my Database.class, made the connection and called the insertnewcustomer method.

public static void main(String[] args) {
    Database db = new Database();
    db.connectDB();
    db.insertNewCustomer(86754312, "arda", "zenci", 55418, 400);
.................//

//and here is my insertNewCustomer method which is inside the Database.class

public void insertNewCustomer(int num, String name, String surname, int phone, int debt){
    try {
        statement.executeUpdate("INSERT INTO Customer(customer_cardno, customer_name, customer_sirname, customer_phone, debt) VALUES(" + num + ", " + name  + ", " + surname + ", " + phone + ", " + debt + ")");
    } catch (SQLException e) {
        e.printStackTrace();
    }}

我看不到任何问题，但我有一个 MySQLSyntaxErrorException

com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column 'arda' in 'field list'
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.Util.getInstance(Util.java:386)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1054)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4187)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4119)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2570)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2731)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2809)
at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1811)
at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1725)
at Database.insertNewCustomer(Database.java:39)
at mainFrame.main(mainFrame.java:50)

Answer 1

发生这种情况是因为您需要用引号将非整数的变量括起来，否则数据库会将它们理解为列，只需在非整数列中添加引号，例如

statement.executeUpdate("INSERT INTO Customer(customer_cardno, customer_name, customer_sirname, customer_phone, debt) VALUES(" + num + ", '" + name  + "', '" + surname + "', " + phone + ", " + debt + ")");

我假设customer_cardno、customer_phone、debt是i tegers列，如果它们不是只是用引号包围variabkes