工具類
工具類轉自C# MysqlHelper C#連接mysql資料庫類別庫全，代碼如下：
using MySql.Data.MySqlClient;
using System;
using System.Data;
namespace ConsoleApp
{
public class MySqlHelper
{
/// <summary>
/// 獲取一個有效的資料庫連接物件
/// </summary>
/// <returns></returns>
public static MySqlConnection GetConnection(string connSting)
{
MySqlConnection Connection = new MySqlConnection(connSting);
return Connection;
}
/// <summary>
/// 給定連接的資料庫用假設引數執行一個sql命令（不回傳資料集）
/// </summary>
/// <param name="connectionString">一個有效的連接字串</param>
/// <param name="cmdType">命令型別(存盤程序, 文本, 等等)</param>
/// <param name="cmdText">存盤程序名稱或者sql命令陳述句</param>
/// <param name="commandParameters">執行命令所用引數的集合</param>
/// <returns>執行命令所影響的行數</returns>
public static int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText, params MySqlParameter[] commandParameters)
{
MySqlCommand cmd = new MySqlCommand();
using (MySqlConnection conn = new MySqlConnection(connectionString))
{
PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return val;
}
}
/// <summary>
/// 用現有的資料庫連接執行一個sql命令（不回傳資料集）
/// </summary>
/// <param name="connection">一個現有的資料庫連接</param>
/// <param name="cmdType">命令型別(存盤程序, 文本, 等等)</param>
/// <param name="cmdText">存盤程序名稱或者sql命令陳述句</param>
/// <param name="commandParameters">執行命令所用引數的集合</param>
/// <returns>執行命令所影響的行數</returns>
public static int ExecuteNonQuery(MySqlConnection connection, CommandType cmdType, string cmdText, params MySqlParameter[] commandParameters)
{
MySqlCommand cmd = new MySqlCommand();
PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return val;
}
/// <summary>
///使用現有的SQL事務執行一個sql命令（不回傳資料集）
/// </summary>
/// <remarks>
///舉例:
/// int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new MySqlParameter("@prodid", 24));
/// </remarks>
/// <param name="trans">一個現有的事務</param>
/// <param name="cmdType">命令型別(存盤程序, 文本, 等等)</param>
/// <param name="cmdText">存盤程序名稱或者sql命令陳述句</param>
/// <param name="commandParameters">執行命令所用引數的集合</param>
/// <returns>執行命令所影響的行數</returns>
public static int ExecuteNonQuery(MySqlTransaction trans, CommandType cmdType, string cmdText, params MySqlParameter[] commandParameters)
{
MySqlCommand cmd = new MySqlCommand();
PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, commandParameters);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return val;
}
/// <summary>
/// 用執行的資料庫連接執行一個回傳資料集的sql命令
/// </summary>
/// <remarks>
/// 舉例:
/// MySqlDataReader r = ExecuteReader(connString, CommandType.StoredProcedure, "PublishOrders", new MySqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">一個有效的連接字串</param>
/// <param name="cmdType">命令型別(存盤程序, 文本, 等等)</param>
/// <param name="cmdText">存盤程序名稱或者sql命令陳述句</param>
/// <param name="commandParameters">執行命令所用引數的集合</param>
/// <returns>包含結果的讀取器</returns>
public static MySqlDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params MySqlParameter[] commandParameters)
{
MySqlCommand cmd = new MySqlCommand();
MySqlConnection conn = new MySqlConnection(connectionString);
try
{
PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
MySqlDataReader reader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
cmd.Parameters.Clear();
return reader;
}
catch
{
conn.Close();
throw;
}
}
/// <summary>
/// 回傳DataSet
/// </summary>
/// <param name="connectionString">一個有效的連接字串</param>
/// <param name="cmdType">命令型別(存盤程序, 文本, 等等)</param>
/// <param name="cmdText">存盤程序名稱或者sql命令陳述句</param>
/// <param name="commandParameters">執行命令所用引數的集合</param>
/// <returns></returns>
public static DataSet GetDataSet(string connectionString, CommandType cmdType, string cmdText, params MySqlParameter[] commandParameters)
{
MySqlCommand cmd = new MySqlCommand();
MySqlConnection conn = new MySqlConnection(connectionString);
try
{
PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
MySqlDataAdapter adapter = new MySqlDataAdapter();
adapter.SelectCommand = cmd;
DataSet ds = new DataSet();
adapter.Fill(ds);
cmd.Parameters.Clear();
conn.Close();
return ds;
}
catch (Exception e)
{
throw e;
}
}
/// <summary>
/// 用指定的資料庫連接字串執行一個命令并回傳一個資料表
/// </summary>
///<param name="connectionString">一個有效的連接字串</param>
/// <param name="cmdType">命令型別(存盤程序, 文本, 等等)</param>
/// <param name="cmdText">存盤程序名稱或者sql命令陳述句</param>
/// <param name="commandParameters">執行命令所用引數的集合</param>
public static DataTable GetDataTable(string connectionString, CommandType cmdType, string cmdText, params MySqlParameter[] commandParameters)
{
MySqlCommand cmd = new MySqlCommand();
MySqlConnection conn = new MySqlConnection(connectionString);
try
{
PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
MySqlDataAdapter adapter = new MySqlDataAdapter();
adapter.SelectCommand = cmd;
DataTable ds = new DataTable();
adapter.Fill(ds);
cmd.Parameters.Clear();
conn.Close();
return ds;
}
catch (Exception e)
{
throw e;
}
}
/// <summary>
/// 用指定的資料庫連接字串執行一個命令并回傳一個資料集的第一列
/// </summary>
/// <remarks>
///例如:
/// Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new MySqlParameter("@prodid", 24));
/// </remarks>
///<param name="connectionString">一個有效的連接字串</param>
/// <param name="cmdType">命令型別(存盤程序, 文本, 等等)</param>
/// <param name="cmdText">存盤程序名稱或者sql命令陳述句</param>
/// <param name="commandParameters">執行命令所用引數的集合</param>
/// <returns>用 Convert.To{Type}把型別轉換為想要的 </returns>
public static object ExecuteScalar(string connectionString, CommandType cmdType, string cmdText, params MySqlParameter[] commandParameters)
{
MySqlCommand cmd = new MySqlCommand();
using (MySqlConnection connection = new MySqlConnection(connectionString))
{
PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
object val = cmd.ExecuteScalar();
cmd.Parameters.Clear();
return val;
}
}
/// <summary>
/// 回傳插入值ID
/// </summary>
/// <param name="connectionString"></param>
/// <param name="cmdType"></param>
/// <param name="cmdText"></param>
/// <param name="commandParameters"></param>
/// <returns></returns>
public static object ExecuteNonExist(string connectionString, CommandType cmdType, string cmdText, params MySqlParameter[] commandParameters)
{
MySqlCommand cmd = new MySqlCommand();
using (MySqlConnection connection = new MySqlConnection(connectionString))
{
PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
object val = cmd.ExecuteNonQuery();
return cmd.LastInsertedId;
}
}
/// <summary>
/// 用指定的資料庫連接執行一個命令并回傳一個資料集的第一列
/// </summary>
/// <remarks>
/// 例如:
/// Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new MySqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connection">一個存在的資料庫連接</param>
/// <param name="cmdType">命令型別(存盤程序, 文本, 等等)</param>
/// <param name="cmdText">存盤程序名稱或者sql命令陳述句</param>
/// <param name="commandParameters">執行命令所用引數的集合</param>
/// <returns>用 Convert.To{Type}把型別轉換為想要的 </returns>
public static object ExecuteScalar(MySqlConnection connection, CommandType cmdType, string cmdText, params MySqlParameter[] commandParameters)
{
MySqlCommand cmd = new MySqlCommand();
PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
object val = cmd.ExecuteScalar();
cmd.Parameters.Clear();
return val;
}
/// <summary>
/// 準備執行一個命令
/// </summary>
/// <param name="cmd">sql命令</param>
/// <param name="conn">OleDb連接</param>
/// <param name="trans">OleDb事務</param>
/// <param name="cmdType">命令型別例如 存盤程序或者文本</param>
/// <param name="cmdText">命令文本,例如:Select * from Products</param>
/// <param name="cmdParms">執行命令的引數</param>
private static void PrepareCommand(MySqlCommand cmd, MySqlConnection conn, MySqlTransaction trans, CommandType cmdType, string cmdText, MySqlParameter[] cmdParms)
{
if (conn.State != ConnectionState.Open)
conn.Open();
cmd.Connection = conn;
cmd.CommandText = cmdText;
if (trans != null)
cmd.Transaction = trans;
cmd.CommandType = cmdType;
if (cmdParms != null)
{
foreach (MySqlParameter parm in cmdParms)
cmd.Parameters.Add(parm);
}
}
}
}
使用方法
這里只列舉了常規的建庫、建表、增刪改查操作，代碼如下：
using MySql.Data.MySqlClient;
using System;
using System.Data;
using System.Text;
namespace ConsoleApp
{
class Program
{
static void Main(string[] args)
{
//建庫
string connSting = "Data Source=localhost;Persist Security Info=yes; UserId=root; PWD=root;";
string cmdText = "CREATE DATABASE IF NOT EXISTS test DEFAULT CHARSET utf8 COLLATE utf8_general_ci;";
MySqlConnection conn = MySqlHelper.GetConnection(connSting);
int val = MySqlHelper.ExecuteNonQuery(conn, CommandType.Text, cmdText);
Console.WriteLine("影響行數："+ val);
//建表
connSting = "server=localhost;Database='test';User='root';Password='root';charset='utf8';pooling=false;SslMode=none";
StringBuilder sbr = new StringBuilder();
sbr.Append("CREATE TABLE IF NOT EXISTS `test_table`(");
sbr.Append("`id` INT UNSIGNED AUTO_INCREMENT,");
sbr.Append("`name` VARCHAR(100) NOT NULL,");
sbr.Append("`password` VARCHAR(40) NOT NULL,");
sbr.Append("`create_time` datetime DEFAULT CURRENT_TIMESTAMP COMMENT '創建時間',");
sbr.Append("`update_time` datetime DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '更新時間',");
sbr.Append("PRIMARY KEY( `id` ));");
cmdText = sbr.ToString();
conn = MySqlHelper.GetConnection(connSting);
val = MySqlHelper.ExecuteNonQuery(conn, CommandType.Text, cmdText);
Console.WriteLine("影響行數：" + val);
//增
sbr.Clear();
sbr.Append("INSERT INTO test_table (name,password) VALUES ");
sbr.Append("(11,111), ");
sbr.Append("(12,222); ");
cmdText = sbr.ToString();
val = MySqlHelper.ExecuteNonQuery(conn, CommandType.Text, cmdText);
Console.WriteLine("影響行數：" + val);
//刪
sbr.Clear();
sbr.Append("DELETE FROM test_table ");
sbr.Append("WHERE id=1;");
cmdText = sbr.ToString();
val = MySqlHelper.ExecuteNonQuery(conn, CommandType.Text, cmdText);
Console.WriteLine("影響行數：" + val);
//改
sbr.Clear();
sbr.Append("UPDATE test_table SET ");
sbr.Append("name='13', ");
sbr.Append("password='333' ");
sbr.Append("WHERE id=@id;");
cmdText = sbr.ToString();
MySqlParameter idParm = new MySqlParameter("@id", 2);
val = MySqlHelper.ExecuteNonQuery(conn, CommandType.Text, cmdText, idParm);
Console.WriteLine("影響行數：" + val);
//查
sbr.Clear();
sbr.Append("SELECT name,password FROM test_table ");
sbr.Append("WHERE id=@id;");
cmdText = sbr.ToString();
DataTable dt= MySqlHelper.GetDataTable(connSting,CommandType.Text,cmdText, idParm);
Console.WriteLine("結果行數：" + dt.Rows.Count);
//測驗Parameters.Clear()的作用
string sqlInsert = "INSERT INTO test_table (name,password) VALUES ( @name ,1233);";
string sqlSelect = "SELECT * FROM test_table WHERE name=@name;";
MySqlParameter parms = new MySqlParameter("@name", "testName");
MySqlHelper.ExecuteNonQuery(connSting, CommandType.Text, sqlInsert, parms);
MySqlHelper.ExecuteNonQuery(connSting, CommandType.Text, sqlSelect, parms);
//洗掉表
sbr.Clear();
sbr.Append("DROP TABLE test_table;");
cmdText = sbr.ToString();
val = MySqlHelper.ExecuteNonQuery(conn, CommandType.Text, cmdText);
Console.WriteLine("影響行數：" + val);
//洗掉資料庫
connSting = "Data Source=localhost;Persist Security Info=yes; UserId=root; PWD=root;";
cmdText = "DROP DATABASE test;";
val = MySqlHelper.ExecuteNonQuery(conn, CommandType.Text, cmdText);
Console.WriteLine("影響行數：" + val);
Console.ReadKey();
}
}
}
關于cmd.Parameters.Clear()的作用，我沒測出什么結果，有沒有都一樣，參考cmd.Parameters.Clear() 陳述句的作用這篇文章，我懷疑問題只存在微軟的Sql資料庫中，
參考資料
MySql-8.0.23-winx64 dll 提取碼：zloa
C#連接MySQL資料庫，并建庫、建表
C# MysqlHelper C#連接mysql資料庫類別庫全
MySQL 教程
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標籤：C#
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