C# 利用 ADO.NET 操作 MySQL 数据库
首先给大家看一下这个小项目的结构（一个 WebAPI 的小项目）：
上面红框里的文件是这篇文章所涉及的主要文件。
首先在你的项目中添加 MySQL 的支持，在 NuGet 上搜索 MySql 并安装第三方库（不要选错了哟~），如下图：
创建一个MySQL数据库连接信息实体类，这个类会替代我们常用的连接字符串，而且可以实现对各个参数的配置、热修改。
/// MySQL数据库连接信息实体类
///
public class MySqlDBConnectInfo
{
/// 唯一别名（用来区分是哪个链接，推荐策略：服务地址-数据库名）
///
public string UniqueAlias { get; set; }
/// 数据库服务连接地址，例："127.0.0.1"
///
public string Server { get; set; }
/// 数据库服务连接端口号
///
public uint Port { get; set; }
/// 连接的数据库
///
public string Database { get; set; }
/// 连接数据库的用户名
///
public string UserID { get; set; }
/// 用户密码
///
public string Password { get; set; }
/// 设置字符编码，例："utf8"
///
public string CharacterSet { get; set; }
/// 连接超时时间，单位秒
///
public uint ConnectionTimeout { get; set; }
/// 数据库执行超时时间，单位秒
///
public uint DefaultCommandTimeout { get; set; }
/// 是否开启连接池，true
///
public bool Pooling { get; set; }
/// 连接池中最小连接数
///
public uint MinimumPoolSize { get; set; }
/// 连接池中最大连接数
///
public uint MaximumPoolSize { get; set; }
/// 连接池中连接对象存活时间，单位秒
///
public uint ConnectionLifeTime { get; set; }
/// 连接是否使用压缩，true
///
public bool UseCompression { get; set; }
/// 表示连接池程序是否会自动登记创建线程的当前事务语境中的连接，ture
///
public bool AutoEnlist { get; set; }
}新建一个类 StartupInitMySqlConfig，用来控制程序启动时初始化MySQL数据库配置信息
/// 启动时初始化MySQL数据库配置信息
///
public static class StartupInitMySqlConfig
{
/// 数据库连接信息配置文件 的 文件名 （MySqlConnectionConfig.xml）
///
private const string MySqlDBConnectConfigFilename = "MySqlConnectionConfig.xml";
/// 唯一别名 的 存储值
///
private static string UniqueAliasSV = string.Empty;
///
/// 唯一别名 锁；避免同时被修改
///
private static readonly object _uniqueAliasLock = new object();
/// 唯一别名（用来区分是哪个链接，推荐策略：服务地址_数据库名）
///
private static string uniqueAlias = string.Empty;
/// 唯一别名（用来区分是哪个链接，推荐策略：服务地址_数据库名）
///
public static string UniqueAlias
{
get { return uniqueAlias; }
set
{
uniqueAlias = value == null ? string.Empty : value;
}
}
/// 声明一个[MySqlDBConnectInfo]数据库连接信息对象
///
private static MySqlDBConnectInfo dbConnectInfo;
/// 获取[MySqlDBConnectInfo]数据库连接信息对象（默认取配置文件中的第一个连接对象）
///
public static MySqlDBConnectInfo DbConnectInfo
{
get
{
try
{
lock (_uniqueAliasLock)
{
try
{
if (dbConnectInfo == null || UniqueAlias != UniqueAliasSV)
{
UniqueAliasSV = UniqueAlias;
string path = AppDomain.CurrentDomain.BaseDirectory + MySqlDBConnectConfigFilename;
if (!File.Exists(path))
{
dbConnectInfo = null;
throw new Exception("系统找不到数据库连接信息配置文件。");
}
else
{
List dbConnectInfoList = XmlTool.XmlFlieToTObject>(path, Encoding.UTF8);
if (string.IsNullOrWhiteSpace(UniqueAliasSV))
{
dbConnectInfo = dbConnectInfoList[0];
}
else
{
foreach (MySqlDBConnectInfo item in dbConnectInfoList)
{
if (item.UniqueAlias == UniqueAliasSV)
{
dbConnectInfo = item;
break;
}
}
}
}
}
}
catch (Exception ex)
{
dbConnectInfo = null;
throw new Exception("数据库连接信息配置文件[MySqlConfig.xml]转数据库连接信息对象[MySqlDBConnectInfo]时失败。\r\n" + ex.ToString());
}
}
}
catch (Exception ex)
{
dbConnectInfo = null;
throw new Exception("数据库连接信息配置文件[MySqlConfig.xml]转数据库连接信息对象[MySqlDBConnectInfo]时失败。\r\n" + ex.ToString());
}
return dbConnectInfo;
}
set { dbConnectInfo = value; }
}
} 下面是一个 MySQL数据库操作工具类【核心功能都在这】
/// MySQL数据库操作工具类
///
public class MySqlTool
{
/// 声明一个[MySqlDBConnectInfo]数据库连接信息对象
///
private MySqlDBConnectInfo mysqlDbConnectInfo;
/// 无参构造函数（获取 MySqlConfig.xml 配置文件中的第一个连接对象）
///
public MySqlTool()
{
StartupInitMySqlConfig.UniqueAlias = string.Empty;
mysqlDbConnectInfo = StartupInitMySqlConfig.DbConnectInfo;
}
/// 有参构造函数（获取 MySqlConfig.xml 配置文件中 UniqueAlias 参数所匹配的唯一别名的连接对象）
///
/// 连接对象的唯一别名，用来区分是哪个链接对象
public MySqlTool(string uniqueAlias)
{
StartupInitMySqlConfig.UniqueAlias = uniqueAlias;
mysqlDbConnectInfo = StartupInitMySqlConfig.DbConnectInfo;
}
/// 声明一个[MySqlConnection]连接对象
///
private MySqlConnection mysqlConnection;
/// 获取[MySqlConnection]连接对象
///
private MySqlConnection MysqlConnection
{
get
{
if (mysqlDbConnectInfo == null)
{
mysqlDbConnectInfo = StartupInitMySqlConfig.DbConnectInfo;
}
if (mysqlConnection == null)
{
try
{
MySqlConnectionStringBuilder connectStr = new MySqlConnectionStringBuilder();
connectStr.Server = mysqlDbConnectInfo.Server;
connectStr.Port = mysqlDbConnectInfo.Port;
connectStr.Database = mysqlDbConnectInfo.Database;
connectStr.UserID = mysqlDbConnectInfo.UserID;
connectStr.Password = mysqlDbConnectInfo.Password;
connectStr.CharacterSet = mysqlDbConnectInfo.CharacterSet;
connectStr.ConnectionTimeout = mysqlDbConnectInfo.ConnectionTimeout;
connectStr.DefaultCommandTimeout = mysqlDbConnectInfo.DefaultCommandTimeout;
connectStr.Pooling = mysqlDbConnectInfo.Pooling;
connectStr.MinimumPoolSize = mysqlDbConnectInfo.MinimumPoolSize;
connectStr.MaximumPoolSize = mysqlDbConnectInfo.MaximumPoolSize;
connectStr.ConnectionLifeTime = mysqlDbConnectInfo.ConnectionLifeTime;
connectStr.UseCompression = mysqlDbConnectInfo.UseCompression;
connectStr.AutoEnlist = mysqlDbConnectInfo.AutoEnlist;
mysqlConnection = new MySqlConnection(connectStr.GetConnectionString(true));
}
catch (Exception ex)
{
mysqlConnection = null;
throw new Exception("创建数据库连接时发生异常。\r\n" + ex.ToString());
}
}
return mysqlConnection;
}
}
/// 获取当前对象已存在的连接信息[MySqlDBConnectInfo]
///
/// 打开数据库连接
///
public void OpenConnect()
{
if (MysqlConnection.State == ConnectionState.Closed)
{
try
{
MysqlConnection.Open();
}
catch (Exception ex)
{
StartupInitMySqlConfig.DbConnectInfo = null;
throw new Exception("打开数据库连接时发生异常。\r\n" + ex.ToString());
}
}
else if (MysqlConnection.State == ConnectionState.Broken)
{
try
{
MysqlConnection.Close();
MysqlConnection.Open();
}
catch (Exception ex)
{
StartupInitMySqlConfig.DbConnectInfo = null;
throw new Exception("打开数据库连接时发生异常。\r\n" + ex.ToString());
}
}
}
/// 关闭数据库连接
///
public void CloseConnect()
{
if (MysqlConnection.State != ConnectionState.Closed)
{
try
{
MysqlConnection.Close();
}
catch (Exception ex)
{
throw new Exception("关闭数据库连接时发生异常。\r\n" + ex.ToString());
}
}
}
/// 声明一个[MySqlTransaction]事务处理对象
///
private MySqlTransaction mysqlTransaction;
/// 开启事务处理
///
public void BeginTransaction()
{
try
{
mysqlTransaction = MysqlConnection.BeginTransaction();
}
catch (Exception ex)
{
throw new Exception("开始事务处理时发生异常。\r\n" + ex.ToString());
}
}
/// 提交事务
///
public void Commit()
{
try
{
if (mysqlTransaction != null)
{
mysqlTransaction.Commit();
mysqlTransaction.Dispose();
mysqlTransaction = null;
}
}
catch (Exception ex)
{
throw new Exception("提交事务时发生异常。\r\n" + ex.ToString());
}
}
/// 回滚事务
///
public void Rollback()
{
try
{
if (mysqlTransaction != null)
{
mysqlTransaction.Rollback();
mysqlTransaction.Dispose();
mysqlTransaction = null;
}
}
catch (Exception ex)
{
throw new Exception("回滚事务时发生异常。\r\n" + ex.ToString());
}
}
/// 执行SQL语句，返回受影响行数
///
/// string：SQL语句
/// Dictionary：SQL参数化
/// int
public int ExecuteNonQuery(string sql, Dictionary dicParam = null)
{
int row = -1;
try
{
using (MySqlCommand command = MysqlConnection.CreateCommand())
{
try
{
command.CommandText = sql;
if (dicParam != null && dicParam.Count > 0)
{
foreach (KeyValuePair kvp in dicParam)
{
command.Parameters.AddWithValue(kvp.Key, kvp.Value);
}
}
row = command.ExecuteNonQuery();
}
catch (Exception ex)
{
row = -1;
throw new Exception("执行SQL语句时发生异常[ExecuteNonQuery()]。\r\n" + ex.ToString());
}
}
}
catch (Exception ex)
{
row = -1;
throw new Exception("执行SQL语句时发生异常[ExecuteNonQuery()]。\r\n" + ex.ToString());
}
return row;
}
/// 执行SQL查询，返回第一行第一列的值（object对象）。【例如：count()函数】
///
/// string：SQL语句
/// Dictionary：SQL参数化
/// object
public object ExecuteScalar(string sql, Dictionary dicParam = null)
{
object obj = null;
try
{
using (MySqlCommand command = MysqlConnection.CreateCommand())
{
try
{
command.CommandText = sql;
if (dicParam != null && dicParam.Count > 0)
{
foreach (KeyValuePair kvp in dicParam)
{
command.Parameters.AddWithValue(kvp.Key, kvp.Value);
}
}
obj = command.ExecuteScalar();
}
catch (Exception ex)
{
obj = null;
throw new Exception("执行SQL语句查询时发生异常[ExecuteScalar()]。\r\n" + ex.ToString());
}
}
}
catch (Exception ex)
{
obj = null;
throw new Exception("执行SQL语句查询时发生异常[ExecuteScalar()]。\r\n" + ex.ToString());
}
return obj;
}
/// 执行SQL查询，返回一个[ MySqlDataReader ]只进只读对象
///
/// string：SQL语句
/// Dictionary：SQL参数化
/// (object)MySqlDataReader
public object ExecuteReader(string sql, Dictionary dicParam = null)
{
MySqlDataReader reader = null;
try
{
using (MySqlCommand command = MysqlConnection.CreateCommand())
{
try
{
command.CommandText = sql;
if (dicParam != null && dicParam.Count > 0)
{
foreach (KeyValuePair kvp in dicParam)
{
command.Parameters.AddWithValue(kvp.Key, kvp.Value);
}
}
reader = command.ExecuteReader();
}
catch (Exception ex)
{
reader = null;
throw new Exception("执行SQL语句查询时发生异常[ExecuteReader()]。\r\n" + ex.ToString());
}
}
}
catch (Exception ex)
{
reader = null;
throw new Exception("执行SQL语句查询时发生异常[ExecuteReader()]。\r\n" + ex.ToString());
}
return reader;
}
/// 执行查询，返回一个DataTable对象
///
/// string：SQL语句
/// Dictionary：SQL参数化
/// DataTable
public DataTable QueryData_DataTable(string sql, Dictionary dicParam = null)
{
DataTable dt = new DataTable();
try
{
using (MySqlDataAdapter da = new MySqlDataAdapter())
{
using (MySqlCommand command = MysqlConnection.CreateCommand())
{
try
{
command.CommandText = sql;
if (dicParam != null && dicParam.Count > 0)
{
foreach (KeyValuePair kvp in dicParam)
{
command.Parameters.AddWithValue(kvp.Key, kvp.Value);
}
}
da.SelectCommand = command;
da.Fill(dt);
}
catch (Exception ex)
{
dt = null;
throw new Exception("执行SQL语句查询时发生异常[QueryData_DataTable()]。\r\n" + ex.ToString());
}
}
}
}
catch (Exception ex)
{
dt = null;
throw new Exception("执行SQL语句查询时发生异常[QueryData_DataTable()]。\r\n" + ex.ToString());
}
return dt;
}
/// 执行查询，返回一个DataSet对象
///
/// string：SQL语句
/// Dictionary：SQL参数化
/// string：映射表名称
/// DataSet
public DataSet QueryData_DataSet(string sql, Dictionary dicParam = null, string srcTable = null)
{
DataSet ds = new DataSet();
try
{
using (MySqlDataAdapter da = new MySqlDataAdapter())
{
using (MySqlCommand command = MysqlConnection.CreateCommand())
{
try
{
command.CommandText = sql;
if (dicParam != null && dicParam.Count > 0)
{
foreach (KeyValuePair kvp in dicParam)
{
command.Parameters.AddWithValue(kvp.Key, kvp.Value);
}
}
da.SelectCommand = command;
if (string.IsNullOrWhiteSpace(srcTable))
{
da.Fill(ds);
}
else
{
da.Fill(ds, srcTable);
}
}
catch (Exception ex)
{
ds = null;
throw new Exception("执行SQL语句查询时发生异常[QueryData_DataSet()]。\r\n" + ex.ToString());
}
}
}
}
catch (Exception ex)
{
ds = null;
throw new Exception("执行SQL语句查询时发生异常[QueryData_DataSet()]。\r\n" + ex.ToString());
}
return ds;
}
/// 新增数据通用方法（字段名数组与字段值数组必须一一对应）
///
/// 数据库表名称
/// 数据库字段名数组
/// 数据库字段值数组
/// dicParam = new Dictionary();
try
{
#region 动态产生SQL语句
sqlStr.AppendLine("INSERT INTO " + tableName);
sqlStr.AppendLine("(");
for (int f = 0; f < fieldArray.Length; f++)
{
if (f == fieldArray.Length - 1)
{
sqlStr.AppendLine(fieldArray[f]);
}
else
{
sqlStr.AppendLine(fieldArray[f] + ",");
}
}
sqlStr.AppendLine(")");
sqlStr.AppendLine("VALUES");
sqlStr.AppendLine("(");
for (int f = 0; f < fieldArray.Length; f++)
{
if (f == fieldArray.Length - 1)
{
sqlStr.AppendLine("?" + fieldArray[f]);
}
else
{
sqlStr.AppendLine("?" + fieldArray[f] + ",");
}
}
sqlStr.AppendLine(")");
#endregion
#region 动态参数赋值
for (int v = 0; v < valueArray.Length; v++)
{
dicParam.Add("?" + fieldArray[v], valueArray[v]);
}
#endregion
#region 执行SQL
row = ExecuteNonQuery(sqlStr.ToString(), dicParam);
#endregion
}
catch (Exception ex)
{
throw new Exception("执行新增通用方法时发生异常[InsertSqlExe()]。\r\n" + ex.ToString());
}
return row;
}
/// 新增数据通用方法（字段名集合与字段值集合必须一一对应）
///
/// 数据库表名称
/// 数据库字段名集合
/// 数据库字段值集合
/// fieldList, List 接下来我们配置启动时代码 Global.asax ：
public class WebApiApplication : HttpApplication
{
protected void Application_Start()
{
GlobalConfiguration.Configure(WebApiConfig.Register);
//启动时读取数据库连接信息配置文件（MySqlConnectionConfig.xml）
try
{
MySqlDBConnectInfo dbConnectInfo = StartupInitMySqlConfig.DbConnectInfo;
if (dbConnectInfo == null)
{
throw new Exception("系统获取不到数据库连接信息。");
}
}
catch (Exception ex)
{
LogTool.WriteErrorLog("【启动异常】从配置文件中获取 MySql 连接信息，发生异常", ex.ToString());
}
}
}MySqlConnectionConfig.xml 配置文件：
185.**.36.12-DBName
185.**.36.12
3306
DBName
UserName
UserPwd
utf8
60
60
true
20
50
1200
true
true
上面代码中用到的 JsonTool 和 XmlTool 都在我之前的博文中。
下面给一个 MySqlTool 的使用例子：
希望给你带来参考和帮助。