语句问题，找大大捉虫

Question

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.OleDb;

namespace EEE3111_EA_210078707
{
    public partial class Form2 : Form
    {
        private OleDbConnection connection = new OleDbConnection();
        public Form2()
        {
            InitializeComponent();
            connection.ConnectionString = @"Provider = Microsoft.ACE.OLEDB.12.0; Data Source =C:\Users\Administrator\Desktop\EEE3111_EA.accdb; Persist Security Info = False;";
        }

        private void Form2_Load(object sender, EventArgs e)
        {
            try
            {
                connection.Open();
                OleDbCommand command = new OleDbCommand();
                command.Connection = connection;
                string query = "select * from EATable";
                //MessageBox.Show(query);
                command.CommandText = query;

                OleDbDataReader reader = command.ExecuteReader();

                while (reader.Read())
                {
                    comboBox1.Items.Add(reader["FirstName"].ToString());
                    listBox1.Items.Add(reader["FirstName"].ToString());
                }
                connection.Close();
            }
            catch (Exception ex)
            {
                MessageBox.Show("Error " + ex);
            }
        }

        private void SAVE_Click(object sender, EventArgs e)
        {
            try
            {
                connection.Open();
                OleDbCommand command = new OleDbCommand();
                command.Connection = connection;
                command.CommandText = "insert into EEE3111_EA(FirstName,LastName,DOB,Country,Phone) values( '" + txt_FirstName + "' , '" + txt_LastName + "', '" + txt_DOB + "' , '" + txt_Country + "', '" + txt_Phone+ "')";
                command.ExecuteNonQuery();
                MessageBox.Show("Data Saved");
                connection.Close();
            }

            catch (Exception ex)
            {
                MessageBox.Show("Error " + ex);
            }
        }

        private void EDIT_Click(object sender, EventArgs e)
        {
            try
            {
                connection.Open();
                OleDbCommand command = new OleDbCommand();
                command.Connection = connection;
                string query =  " FirstName='" + txt_FirstName.Text + "', LastName='" + txt_LastName.Text + "',DOB= '" + txt_DOB.Text + "',Country= '" + txt_Country.Text+ "',Phone = '" + txt_Phone.Text + ", EID='" + txt_EID.Text + "";

                MessageBox.Show(query);
                command.CommandText = query;

                command.ExecuteNonQuery();
                MessageBox.Show("Data Edit Successful");
                connection.Close();
            }
            catch (Exception ex)
            {
                MessageBox.Show("Error " + ex);
            }
        }

        private void DELETE_Click(object sender, EventArgs e)
        {
            try
            {
                connection.Open();
                OleDbCommand command = new OleDbCommand();
                command.Connection = connection;
                string query = "delete from EATable where EID=" + txt_EID.Text + "";

                //MessageBox.Show(query);
                command.CommandText = query;

                command.ExecuteNonQuery();
                MessageBox.Show("Data Deleted");
                connection.Close();
            }
            catch (Exception ex)
            {
                MessageBox.Show("Error " + ex);
            }
        }

        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            try
            {
                connection.Open();
                OleDbCommand command = new OleDbCommand();
                command.Connection = connection;
                string query = "select * from EATable where FirstName = '" +
                comboBox1.Text + "'";
                command.CommandText = query;

                OleDbDataReader reader = command.ExecuteReader();

                while (reader.Read())
                {
                    txt_EID.Text = reader["EID"].ToString();
                    txt_FirstName.Text = reader["FirstName"].ToString();
                    txt_LastName.Text = reader["LastName"].ToString();
                    txt_DOB.Text = reader["DOB"].ToString();
                    txt_Country.Text = reader["Country"].ToString();
                    txt_Phone.Text = reader["Phone"].ToString();
                }
                connection.Close();
            }
            catch (Exception ex)
            {
                MessageBox.Show("Error " + ex);
            }
        }

        private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            try
            {
                connection.Open();
                OleDbCommand command = new OleDbCommand();
                command.Connection = connection;
                string query = "select * from EATable where FirstName = '" +
                listBox1.Text + "'";
                command.CommandText = query;
                OleDbDataReader reader = command.ExecuteReader();
                while (reader.Read())
                {
                    txt_EID.Text = reader["EID"].ToString();
                    txt_FirstName.Text = reader["FirstName"].ToString();
                    txt_LastName.Text = reader["LastName"].ToString();
                    txt_DOB.Text = reader["DOB"].ToString();
                    txt_Country.Text = reader["Country"].ToString();
                    txt_Phone.Text = reader["Phone"].ToString();
                }
                connection.Close();
            }
            catch (Exception ex)
            {
                MessageBox.Show("Error " + ex);
            }
        }
    }
}

Answer 1

报错的是76行的sql语句。更新的话要用update，自己注意天更加id的条件，如果是根据eid更新改成下面的。 where EID=" + txt_EID.Text

string query =  "update EATable  set FirstName='" + txt_FirstName.Text + "', LastName='" + txt_LastName.Text + "',DOB= '" + txt_DOB.Text + "',Country= '" + txt_Country.Text+ "',Phone = '" + txt_Phone.Text + " where EID='" + txt_EID.Text + "'";

注意如果eid数据库是数字用下面的

string query =  "update EATable  set FirstName='" + txt_FirstName.Text + "', LastName='" + txt_LastName.Text + "',DOB= '" + txt_DOB.Text + "',Country= '" + txt_Country.Text+ "',Phone = '" + txt_Phone.Text + " where EID=" + txt_EID.Text ;