Question

如何使用连接器/网络编程创建数据库？为什么以下不起作用？

    string connStr = "server=localhost;user=root;port=3306;password=mysql;";
    MySqlConnection conn = new MySqlConnection(connStr);
    MySqlCommand cmd;
    string s0;

    try
    {
        conn.Open();
        s0 = "CREATE DATABASE IF NOT EXISTS `hello`;";
        cmd = new MySqlCommand(s0, conn);
        conn.Close();
    }
    catch (Exception e)
    {
        Console.WriteLine(e.ToString());
    }

Answer 1

您需要执行命令并确保正确处理对象：

string connStr = "server=localhost;user=root;port=3306;password=mysql;";
using (var conn = new MySqlConnection(connStr))
using (var cmd = conn.CreateCommand())
{
    conn.Open();
    cmd.CommandText = "CREATE DATABASE IF NOT EXISTS `hello`;";
    cmd.ExecuteNonQuery();
}

Answer 2

您可能想要执行MySqlCommand。现在您只需创建一个，但它不会执行您的查询。

试试这个：

conn.Open();
s0 = "CREATE DATABASE IF NOT EXISTS `hello`;";
cmd = new MySqlCommand(s0, conn);
cmd.ExecuteNonQuery();
conn.Close();

Answer 3

执行您的命令并尝试此功能

public void createDatabase(string server, string port, string database, string username, string password)
    {
        string connectionstring = string.Format("Server = {0}; Port ={1}; Uid = {2}; Pwd = {3}; pooling = true; Allow Zero Datetime = False; Min Pool Size = 0; Max Pool Size = 200; ", server, port, username, password);
        using (var con = new MySqlConnection { ConnectionString = connectionstring })
        {
            using (var command = new MySqlCommand { Connection = con })
            {
                if (con.State == ConnectionState.Open)
                    con.Close();

                try
                {
                    con.Open();
                }
                catch (MySqlException ex)
                {
                    msgErr(ex.Message + " connection error.");
                    return;
                }

                try
                {
                    command.CommandText = @"CREATE DATABASE IF NOT EXISTS @database";
                    command.Parameters.AddWithValue("@database", database);
                    command.ExecuteNonQuery();//Execute your command
                }
                catch (MySqlException ex)
                {
                    msgErr(ex.Message + " sql query error.");
                    return;
                }
            }
        }

    }

Answer 4

导入MySql.Data.MySqlClient 公共类Form1 私有dBf As String =＆＃34; Empresa＆＃34; Private str As String =＆＃34; Server = localhost; UID =根; PWD =;数据库= MySQL的;池=假;＆＃34; Private Cmd As MySqlCommand Private Con As New MySqlConnection（str） Private Sub Form1_Load（）处理MyBase.Load 尝试 Con.Open（） Cmd =新的MySqlCommand（＆＃34;创建数据库，如果不存在＆＃34; + dBf，Con） Cmd.ExecuteNonQuery（）：Con.ChangeDatabase（dBf） Cmd = Con.CreateCommand Cmd.CommandText =＆＃34; CREATE TABLE Empleado＆＃34; ＆安培; ＆＃34;（Id Char（10）COLLATE utf8_spanish_ci Not Null，＆＃34;＆amp; ＆＃34;名称VarChar（50）COLLATE utf8_spanish_ci Not Null，＆＃34; ＆安培; ＆＃34;电子邮件VarChar（50）COLLATE utf8_spanish_ci Not Null，＆＃34; ＆安培; ＆＃34;网站VarChar（50）COLLATE utf8_spanish_ci Not Null，＆＃34; ＆安培; ＆＃34;主键（id））ENGINE = MyISAM＆＃34; Cmd.ExecuteNonQuery（） MsgBox（＆＃34; Registros，ok !!!＆＃34;）：Con.Close（）赶上前例外 MSGBOX（Err.Description）结束尝试结束子结束班

使用Connector / NET编程创建数据库？

4 个答案: