向 MDB 插入和更新数据

Posted 2023-05-07

【中文标题】向 MDB 插入和更新数据

【英文标题】：Inserting and Updating data to MDB

【发布时间】：2011-12-24 16:11:58

【问题描述】：

我正在尝试制作一个简单的测试程序，它可以打开 MDB 文件并执行 3 项基本操作 MDB 有 3 个字段，它们都是文本：

ID
INFO 
TEXT

根据 ID 显示数据 = 得到这个工作 根据 ID 更改数据 = 问题 添加新数据 = 问题

演出数据使用此代码：

con = new OleDbConnection("Provider = Microsoft.Jet.OLEDB.4.0; Data Source = c:\\mdb\\testmdb.mdb");
cmd = new OleDbCommand();
cmd.Connection = con;
cmd.CommandText = "select Info, text from Table1 where ID = '" + int.Parse(textBox1.Text) + "' ";
con.Open(); // open the connection
OleDbDataReader dr = cmd.ExecuteReader();
while (dr.Read())

  textBox2.Text = dr["Info"].ToString();
  textBox3.Text = dr["text"].ToString();

con.Close();

如何在 MDB 中插入新数据并更新已有数据？

【参考方案1】：

试试这个插入：

con = new OleDbConnection("Provider = Microsoft.Jet.OLEDB.4.0; Data Source = c:\\mdb\\testmdb.mdb");
cmd = new OleDbCommand();
cmd.Connection = con;
cmd.CommandText = "insert (ID, Info, text) into Table1 values (@ID, @Info, @text);";
cmd.Parameters.AddWithValue("@ID", textBox1.Text);
cmd.Parameters.AddWithValue("@Info", textBox2.Text);
cmd.Parameters.AddWithValue("@text", textBox3.Text);
con.Open(); // open the connection
//OleDbDataReader dr = cmd.ExecuteNonQuery();
cmd.ExecuteNonQuery();
con.Close();

试试这个更新：

con = new OleDbConnection("Provider = Microsoft.Jet.OLEDB.4.0; Data Source = c:\\mdb\\testmdb.mdb");
cmd = new OleDbCommand();
cmd.Connection = con;
cmd.CommandText = "update Table1 set [Info] = @Info, [text] = @text where ID = @ID;";
cmd.Parameters.AddWithValue("@ID", textBox1.Text);
cmd.Parameters.AddWithValue("@Info", textBox2.Text);
cmd.Parameters.AddWithValue("@text", textBox3.Text);
con.Open(); // open the connection
//OleDbDataReader dr = cmd.ExecuteNonQuery();
cmd.ExecuteNonQuery();
con.Close();

更多操作，请查看this站点的左侧面板。

【讨论】：

现在使用Using 括号可能被认为是最佳实践。另外，您不需要那些数据阅读器，只需致电cmd.ExecuteNonQuery();

错误 2 无法将类型“int”隐式转换为“System.Data.OleDb.OleDbDataReader”

ExecuteNonQuery 的返回值是一个 int，将那些 'OleDbDataReader dr' 行转换为 'int numAffected'，它应该可以正常工作

OK 插入工作，但我仍然有更新“UPDATE 语句中的语法错误”的问题。

TEXT 根据this page 似乎是保留字。尝试将text 放入括号中，例如[text]。

【参考方案2】：

工作代码

using System;
using ADOX;
using System.Data.OleDb;
using System.Data;
using System.IO;

namespace ConsoleApplication4

class Program

    static void Main(string[] args)
    
        CreateMdb("toster_ru.mdb");
        string fileNameWithPath = Environment.CurrentDirectory + "\\toster_ru.mdb";

        CreateTableInToMdb(fileNameWithPath);
        InsertToMdb(fileNameWithPath);
        UpdateToMdb(fileNameWithPath);

        var myDataTable = new DataTable();
        using (var conection = new OleDbConnection("Provider = Microsoft.JET.OLEDB.4.0;  Data Source = " + fileNameWithPath))
        
            conection.Open();
            var query = "Select info From my_table";
            var adapter = new OleDbDataAdapter(query, conection);
            adapter.Fill(myDataTable); 
            Console.WriteLine(myDataTable.Rows[0][0].ToString()); //output: toster2.ru
            Console.ReadKey();
        
    

    static void CreateMdb(string fileNameWithPath)
    
        if (File.Exists(fileNameWithPath))
            return;

        Catalog cat = new Catalog();
        string connstr = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=0;Jet OLEDB:Engine Type=5";
        cat.Create(String.Format(connstr, fileNameWithPath));
        cat = null; 
    

    static void InsertToMdb(string fileNameWithPath)
    
        var con = new OleDbConnection("Provider = Microsoft.Jet.OLEDB.4.0; Data Source = " + fileNameWithPath);
        var cmd = new OleDbCommand();
        cmd.Connection = con;
        cmd.CommandText = "insert into my_table (ID, [Info], [text])  values (@ID, @Info, @text);";
        cmd.Parameters.AddWithValue("@ID", 1);
        cmd.Parameters.AddWithValue("@Info", "toster.ru");
        cmd.Parameters.AddWithValue("@text", "blabla");
        con.Open(); 
        cmd.ExecuteNonQuery();
        con.Close();
    

    static void UpdateToMdb(string fileNameWithPath)
    
        var con = new OleDbConnection("Provider = Microsoft.Jet.OLEDB.4.0; Data Source = " + fileNameWithPath);
        var cmd = new OleDbCommand();
        cmd.Connection = con;
        cmd.CommandText = "UPDATE my_table SET [Info] = ?, [text] = ? WHERE ID = ?;";
        cmd.Parameters.AddWithValue("@p1", OleDbType.VarChar).Value = "toster2.ru";
        cmd.Parameters.AddWithValue("@p2", OleDbType.VarChar).Value = "blabla2";
        cmd.Parameters.AddWithValue("@p3", OleDbType.VarNumeric).Value = 1;
        con.Open();
        cmd.ExecuteNonQuery();
        con.Close();
    

    static void CreateTableInToMdb(string fileNameWithPath)
    
        try
        
            OleDbConnection myConnection = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0; Data Source=" + fileNameWithPath);
            myConnection.Open();
            OleDbCommand myCommand = new OleDbCommand();
            myCommand.Connection = myConnection;
            myCommand.CommandText = "CREATE TABLE my_table([ID] NUMBER, [Info] TEXT, [text] TEXT)";
            myCommand.ExecuteNonQuery();
            myCommand.Connection.Close();
        
        catch