Question

我正在尝试使用自动生成的密钥在Derby数据库中插入记录，我收到此错误：

线程中的异常＆＃34; main＆＃34; java.sql.SQLIntegrityConstraintViolationException：Column＆＃39; CUSTOMERID＆＃39;不能接受NULL值。 at org.apache.derby.client.am.SQLExceptionFactory.getSQLException（未知来源） at org.apache.derby.client.am.SqlException.getSQLException（未知来源）在org.apache.derby.client.am.ClientPreparedStatement.executeUpdate（未知来源）在jakub.ordereditor.OrderEditorMain.create（OrderEditorMain.java:54）在jakub.ordereditor.OrderEditorMain.main（OrderEditorMain.java:39）引起：ERROR 23502：专栏＆＃39; CUSTOMERID＆＃39;不能接受NULL值。 at org.apache.derby.client.am.ClientStatement.completeExecute（Unknown Source）在org.apache.derby.client.net.NetStatementReply.parseEXCSQLSTTreply（未知来源）在org.apache.derby.client.net.NetStatementReply.readExecute（未知来源）在org.apache.derby.client.net.StatementReply.readExecute（未知来源） at org.apache.derby.client.net.NetPreparedStatement.readExecute_（未知来源） at org.apache.derby.client.am.ClientPreparedStatement.readExecute（Unknown Source） at org.apache.derby.client.am.ClientPreparedStatement.flowExecute（Unknown Source）在org.apache.derby.client.am.ClientPreparedStatement.executeUpdateX（未知来源） ......还有3个

我按照这个答案：https://stackoverflow.com/a/1915197和其他许多人。我的代码：

package jan.ordereditor;

import jan.ordereditor.customer.entity.Customer;
import jan.ordereditor.customer.entity.CustomerName;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;


public class OrderEditorMain {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) throws SQLException {

        Customer customer = new Customer();

        CustomerName customerFullName = new CustomerName();
        customerFullName.setCustomerFirstName("John");
        customerFullName.setCustomerSurname("Doe");

        customer.setCustomerFullName(customerFullName);

        create(customer);

    }

    public static void create(Customer customer) throws SQLException {
        String SQL_INSERT = "INSERT INTO customer (customerFirstName, customerSurname) VALUES (?,?)";
        try (
                Connection connection = DriverManager.getConnection("jdbc:derby://localhost:1527/OrderEditor");
                PreparedStatement statement = connection.prepareStatement(SQL_INSERT,
                        Statement.RETURN_GENERATED_KEYS);) {
            CustomerName customerFullName = customer.getCustomerFullName();
            statement.setString(1, customerFullName.getCustomerFirstName());
            statement.setString(2, customerFullName.getCustomerSurname());


            int affectedRows = statement.executeUpdate();

            if (affectedRows == 0) {
                throw new SQLException("Creating user failed, no rows affected.");
            }

            try (ResultSet generatedKeys = statement.getGeneratedKeys()) {
                if (generatedKeys.next()) {
                    customer.setCustomerId(generatedKeys.getInt(1));
                } else {
                    throw new SQLException("Creating user failed, no ID obtained.");
                }
            }
        }
    }

}

和我在数据库Derby中的数据库ID：

Answer 1

您需要删除并读取表格中的customerid列作为标识列。

示例：

ALTER TABLE TableName add customerid int identity(1,1)

从1开始，在每次插入时，值将增加1。

试图插入ID并获取＆＃34;不能接受NULL值＆＃34;

1 个答案: