MySql数据库连接操作

namespace CiWong.LearningLevelApi.MySqlHelp
{
/// <summary>
/// MySqlHelper 类是基于.net框架开发的数据库操作类
/// </summary>
public class MySqlHelper
{
#region 缓存Hashtable
// 存储缓存参数的Hashtable
private static Hashtable parmCache = Hashtable.Synchronized(new Hashtable());
#endregion

#region 重载+1 获取连接字符串
/// <summary>
/// 重载+1 获取连接字符串 [GetStrCon()]
/// </summary>
/// <returns>连接字符串(如果配置文件中无[SQL]名称的连接字符串，则抛出异常)</returns>
public static string GetStrCon()
{
try
{
string CONN_STRING = ConfigurationManager.ConnectionStrings["QuesContext"].ConnectionString;
return CONN_STRING;
}
catch (Exception ex)
{
Console.WriteLine(string.Format("配置文件中没有[SQL]名称的connectionStrings！错误原因：{0}", ex.ToString()));
throw;
}
}
#endregion

#region 重载+2 获取连接字符串
/// <summary>
/// 重载+2 获取连接字符串 [GetStrCon(string strConfig)]
///     如果配置文件中有strConfig为名称的连接字符串，则
///         获取它的内容
///     如果没有，则默认strConfig为连接字符串
/// </summary>
/// <param name="strConfig">配置文件中连接字符串的名称</param>
/// <returns>连接字符串</returns>
public static string GetStrCon(string strConfig)
{
string CONN_STRING = string.Empty;
if (ConfigurationManager.ConnectionStrings[strConfig] != null)
CONN_STRING = ConfigurationManager.ConnectionStrings[strConfig].ConnectionString;
else
CONN_STRING = strConfig;
return CONN_STRING;
}
#endregion

#region 重载+1 创建连接对象 [GetConn()]
/// <summary>
/// 重载+1 返回 conn连接对象 [GetConn()]
/// </summary>
/// <returns> MySqlConnection </returns>
public static MySqlConnection GetConn()
{
try
{
return new MySqlConnection(GetStrCon());
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
throw;
}
}
#endregion

#region 重载+2 创建连接对象 [GetConn()]
/// <summary>
/// 重载+2 返回 conn连接对象 [GetConn()]
///     如果配置文件中有strConfig名称的连拉字符串，则
///         获取它的内容
///     如果没有，则默认strConfig为连接字符串
/// </summary>
/// <param name="strConfig">配置文件中连接字符串的名称</param>
/// <returns> MySqlConnection </returns>
public static MySqlConnection GetConn(string strConfig)
{
try
{
return new MySqlConnection(GetStrCon(strConfig));
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
throw;
}
}
#endregion

#region 关闭连接[CloseConn(...)]
/// <summary>
/// 关闭 conn连接对象
/// </summary>
/// <param name="conn">连接对象</param>
public static void CloseConn(MySqlConnection conn)
{
if (conn.State != ConnectionState.Closed)
conn.Close();
}
#endregion

#region 清空与指定连接相关的连接池
/// <summary>
/// 清空与指定连接相关的连接池 [ClosePool(MySqlConnection conn)]
/// </summary>
public static void ClosePool(MySqlConnection conn)
{
MySqlConnection.ClearPool(conn);
}
#endregion

#region 清空所有连接池
/// <summary>
/// 清空所有连接池 [ClosePool()]
/// </summary>
public static void ClosePool()
{
MySqlConnection.ClearAllPools();
}
#endregion

#region 返回MySqlCommand对象[GetCmd(...)]
/// <summary>
/// 返回MySqlCommand对象
/// </summary>
/// <param name="conn">conn 连接对象</param>
/// <param name="trans">事物对象</param>
/// <param name="cmdType">SQL 执行的类型</param>
/// <param name="cmdText">SQL	执行语句</param>
/// <param name="cmdParms">MySqlParameter[] 对象</param>
/// <returns> 返回comm 对象</returns>
public static MySqlCommand GetCmd(MySqlConnection conn, MySqlTransaction trans, CommandType cmdType, string cmdText, params MySqlParameter[] cmdParms)
{
try
{
if (conn.State != ConnectionState.Open)
conn.Open();

MySqlCommand cmd = new MySqlCommand();
cmd.Connection = conn;
cmd.CommandType = cmdType;
cmd.CommandText = cmdText;

if (trans != null)
cmd.Transaction = trans;

if (cmdParms != null)
{
foreach (MySqlParameter parm in cmdParms)
cmd.Parameters.Add(parm);
}

return cmd;
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
throw;
}
}
#endregion

#region 重载+1 通过连接字符串，执行SqlCommand(不返回结果集)[ExecuteNonQuery(...)]
/// <summary>
/// 重载+1 通过连接字符串，执行SqlCommand(不返回结果集)
/// 利用提供的参数值
/// </summary>
/// <remarks>
/// e.g.:
///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new MySqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connString">为MySqlConnection对象提供：一个有效的连接字符串</param>
/// <param name="cmdType">命令类别：存储过程、文本字符串等</param>
/// <param name="cmdText">存储过程名称或SQL命令文本</param>
/// <param name="cmdParms">执行命令的参数列表</param>
/// <returns>执行命令受影响的记录条数</returns>
public static int ExecuteNonQuery(string connString, CommandType cmdType, string cmdText, params MySqlParameter[] cmdParms)
{
try
{
MySqlCommand cmd = new MySqlCommand();

using (MySqlConnection conn = new MySqlConnection(connString))
{
PrepareCommand(cmd, conn, null, cmdType, cmdText, cmdParms);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
cmd.Dispose();
return val;
}
}
catch (Exception ex)
{
//引发异常，没有记录受影响
Console.WriteLine(ex.ToString());
throw;
}
}
#endregion

#region 重载+2 通过存在的MySqlConnection对象，执行MySqlCommand(不返回结果集)[ExecuteNonQuery(...)]
/// <summary>
/// 重载+2 通过存在的MySqlConnection对象，执行MySqlCommand(不返回结果集)
/// 利用提供的参数值
/// </summary>
/// <remarks>
/// e.g.:
///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders", new MySqlParameter("@prodid", 24));
/// </remarks>
/// <param name="conn">一个已经存在的SqlConnection对象</param>
/// <param name="cmdType">命令类别：存储过程、文本字符串等</param>
/// <param name="cmdText">存储过程名称或SQL命令文本</param>
/// <param name="cmdParms">执行命令的参数列表</param>
/// <returns>执行命令受影响的记录条数</returns>
public static int ExecuteNonQuery(MySqlConnection conn, CommandType cmdType, string cmdText, params MySqlParameter[] cmdParms)
{
try
{
MySqlCommand cmd = new MySqlCommand();

PrepareCommand(cmd, conn, null, cmdType, cmdText, cmdParms);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
cmd.Dispose();
return val;
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
//引发异常，没有记录受影响
throw;
}
finally
{
conn.Close();
}
}
#endregion

#region 重载+3  通过存在的 MySqlTransaction，执行MySqlCommand(不返回结果集)[ExecuteNonQuery(...)]
/// <summary>
/// 重载+3  通过存在的 MySqlTransaction，执行MySqlCommand(不返回结果集)
/// 利用提供的参数值
/// </summary>
/// <remarks>
/// e.g.:
///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "PublishOrders", new MySqlParameter("@prodid", 24));
/// </remarks>
/// <param name="trans">一个已经存在的 trans</param>
/// <param name="cmdType">命令类别：存储过程、文本字符串等</param>
/// <param name="cmdText">存储过程名称或SQL命令文本</param>
/// <param name="cmdParms">执行命令的参数列表</param>
/// <returns>执行命令受影响的记录条数</returns>
public static int ExecuteNonQuery(MySqlTransaction trans, CommandType cmdType, string cmdText, params MySqlParameter[] cmdParms)
{
try
{
MySqlCommand cmd = new MySqlCommand();

PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, cmdParms);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
cmd.Dispose();
return val;
}
catch (Exception ex)
{
//引发异常，没有记录受影响
Console.WriteLine(ex.ToString());
throw;
}
finally
{
trans.Connection.Close();
}
}
#endregion

#region 重载+1 通过连接字符串，执行MySqlCommand(返回结果集)  [ExecuteDataSet(...)]
/// <summary>
/// 重载+1 通过连接字符串，执行MySqlCommand(返回结果集)
/// 利用提供的参数值
/// </summary>
/// <remarks>
/// e.g.:
///  DataSet ds = ExecuteDataSet(connString, CommandType.StoredProcedure, "PublishOrders", new MySqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connString">为MySqlConnection对象提供：一个有效的连接字符串</param>
/// <param name="cmdType">命令类别：存储过程、文本字符串等</param>
/// <param name="cmdText">存储过程名称或SQL命令文本</param>
/// <param name="cmdParms">执行命令的参数列表</param>
/// <returns>返回一个结果集：DataSet对象</returns>
public static DataSet ExecuteDataSet(string connString, CommandType cmdType, string cmdText, params MySqlParameter[] cmdParms)
{
DataSet ds = new DataSet();
//使用一个异常，如果发生异常，则将连接关闭
try
{
using (MySqlConnection conn = new MySqlConnection(connString))
{
MySqlCommand cmd = new MySqlCommand();
PrepareCommand(cmd, conn, null, cmdType, cmdText, cmdParms);
MySqlDataAdapter adp = new MySqlDataAdapter(cmd);
adp.Fill(ds);
cmd.Parameters.Clear();
cmd.Dispose();
return ds;
}
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
throw;
}
}
#endregion

#region 重载+2 通过已经存在的MySqlConnection对象，执行MySqlCommand(返回结果集)  [ExecuteDataSet(...)]
/// <summary>
/// 重载+2 通过已经存在的MySqlConnection对象，执行MySqlCommand(返回结果集)
/// 利用提供的参数值
/// </summary>
/// <remarks>
/// e.g.:
///  DataSet ds = ExecuteDataSet(conn, CommandType.StoredProcedure, "PublishOrders", new MySqlParameter("@prodid", 24));
/// </remarks>
/// <param name="conn">一个已经存在的MySqlConnection对象</param>
/// <param name="cmdType">命令类别：存储过程、文本字符串等</param>
/// <param name="cmdText">存储过程名称或SQL命令文本</param>
/// <param name="cmdParms">执行命令的参数列表</param>
/// <returns>返回一个结果集：DataSet对象</returns>
public static DataSet ExecuteDataSet(MySqlConnection conn, CommandType cmdType, string cmdText, params MySqlParameter[] cmdParms)
{
DataSet ds = new DataSet();
//使用一个异常，如果发生异常，则将连接关闭
try
{
MySqlCommand cmd = new MySqlCommand();
PrepareCommand(cmd, conn, null, cmdType, cmdText, cmdParms);
MySqlDataAdapter adp = new MySqlDataAdapter(cmd);
adp.Fill(ds);
cmd.Parameters.Clear();
cmd.Dispose();
return ds;
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
throw;
}
finally
{
conn.Close();
}
}
#endregion

#region 重载+1 通过连接字符串，执行MySqlCommand(返回结果集的一个MySqlDataReader对象)[ExecuteReader(...)]
/// <summary>
/// 重载+1 通过连接字符串，执行MySqlCommand(返回结果集的一个MySqlDataReader对象)
/// 利用提供的参数值
/// </summary>
/// <remarks>
/// e.g.:
///  MySqlDataReader r = ExecuteReader(connString, CommandType.StoredProcedure, "PublishOrders", new MySqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connString">为MySqlConnection对象提供：一个有效的连接字符串</param>
/// <param name="cmdType">命令类别：存储过程、文本字符串等</param>
/// <param name="cmdText">存储过程名称或SQL命令文本</param>
/// <param name="cmdParms">执行命令的参数列表</param>
/// <returns>包含结果集的一个：MySqlDataReader对象</returns>
public static MySqlDataReader ExecuteReader(string connString, CommandType cmdType, string cmdText, params MySqlParameter[] cmdParms)
{
MySqlConnection conn = new MySqlConnection(connString);

//使用一个异常，如果发生异常，则将连接关闭
try
{
MySqlCommand cmd = new MySqlCommand();
PrepareCommand(cmd, conn, null, cmdType, cmdText, cmdParms);
MySqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
cmd.Parameters.Clear();
cmd.Dispose();
return rdr;
}
catch (Exception ex)
{
CloseConn(conn);
Console.WriteLine(ex.ToString());
throw;
}
}
#endregion

#region 重载+2 通过已经存在的MySqlConnection对象，执行MySqlCommand(返回结果集的一个MySqlDataReader对象) [ExecuteReader(...)]
/// <summary>
/// 重载+2 通过已经存在的MySqlConnection对象，执行MySqlCommand(返回结果集的一个MySqlDataReader对象)
/// 利用提供的参数值
/// </summary>
/// <remarks>
/// e.g.:
///  MySqlDataReader r = ExecuteReader(conn, CommandType.StoredProcedure, "PublishOrders", new MySqlParameter("@prodid", 24));
/// </remarks>
/// <param name="conn">一个已经存在的SqlConnection对象</param>
/// <param name="cmdType">命令类别：存储过程、文本字符串等</param>
/// <param name="cmdText">存储过程名称或SQL命令文本</param>
/// <param name="cmdParms">执行命令的参数列表</param>
/// <returns>包含结果集的一个：MySqlDataReader对象</returns>
public static MySqlDataReader ExecuteReader(MySqlConnection conn, CommandType cmdType, string cmdText, params MySqlParameter[] cmdParms)
{
//使用一个异常，如果发生异常，则将连接关闭
try
{
MySqlCommand cmd = new MySqlCommand();
PrepareCommand(cmd, conn, null, cmdType, cmdText, cmdParms);
MySqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
cmd.Parameters.Clear();
cmd.Dispose();
return rdr;
}
catch (Exception ex)
{
CloseConn(conn);
Console.WriteLine(ex.ToString());
throw;
}
}
#endregion

#region 重载+1 通过连接字符串，执行MySqlCommand [ExecuteScalar(...)]
/// <summary>
/// 重载+1 通过连接字符串，执行MySqlCommand(返回第一条记录的第一列的值，一般是返回汇总值等;如：select max(id) from userTab)
/// 利用提供的参数值
/// </summary>
/// <remarks>
/// e.g.:
///  Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new MySqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connString">为MySqlConnection对象提供：一个有效的连接字符串</param>
/// <param name="cmdType">命令类别：存储过程、文本字符串等</param>
/// <param name="cmdText">存储过程名称或SQL命令文本</param>
/// <param name="cmdParms">执行命令的参数列表</param>
/// <returns>返回一个对象：如果要使用具体的值，需要使用Convert.To{Type}进行转换</returns>
public static object ExecuteScalar(string connString, CommandType cmdType, string cmdText, params MySqlParameter[] cmdParms)
{
try
{
MySqlCommand cmd = new MySqlCommand();

using (MySqlConnection conn = new MySqlConnection(connString))
{
PrepareCommand(cmd, conn, null, cmdType, cmdText, cmdParms);
object val = cmd.ExecuteScalar();
cmd.Parameters.Clear();
cmd.Dispose();
return val;
}
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
throw;
}
}
#endregion

#region 重载+2 通过已经存在的MySqlConnection对象，执行MySqlCommand [ExecuteScalar(...)]
/// <summary>
/// 重载+2 通过已经存在的MySqlConnection对象，执行MySqlCommand(返回第一条记录的第一列的值，一般是返回汇总值等;如：Select max(ColumnName) From TableName)
/// 利用提供的参数值
/// </summary>
/// <remarks>
/// e.g.:
///  Object obj = ExecuteScalar(conn, CommandType.StoredProcedure, "PublishOrders", new MySqlParameter("@prodid", 24));
/// </remarks>
/// <param name="conn">一个已经存在的SqlConnection对象</param>
/// <param name="cmdType">命令类别：存储过程、文本字符串等</param>
/// <param name="cmdText">存储过程名称或SQL命令文本</param>
/// <param name="cmdParms">执行命令的参数列表</param>
/// <returns>返回一个对象：如果要使用具体的值，需要使用Convert.To{Type}进行转换</returns>
public static object ExecuteScalar(MySqlConnection conn, CommandType cmdType, string cmdText, params MySqlParameter[] cmdParms)
{
try
{
MySqlCommand cmd = new MySqlCommand();

PrepareCommand(cmd, conn, null, cmdType, cmdText, cmdParms);
object val = cmd.ExecuteScalar();
cmd.Parameters.Clear();
cmd.Dispose();
return val;
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
throw;
}
finally
{
CloseConn(conn);
}
}
#endregion

#region 将参数数组增加至Hashtable，缓存在缓冲区 [CacheParameters(...)]
/// <summary>
/// 存储：将参数数组增加至缓冲区
/// </summary>
/// <param name="cacheKey">缓冲区参数的键名</param>
/// <param name="cmdParms">缓冲区对应键名的参数值</param>
public static void CacheParameters(string cacheKey, params MySqlParameter[] cmdParms)
{
parmCache[cacheKey] = cmdParms;
}
#endregion

#region 从缓冲区得到Hashtable中的参数列表的值 [GetCachedParameters(...)]
/// <summary>
/// 检索值：得到缓冲区中的参数列表值
/// </summary>
/// <param name="cacheKey">缓冲区参数的键名</param>
/// <returns>缓冲区对应键名的参数值</returns>
public static MySqlParameter[] GetCachedParameters(string cacheKey)
{
//获取 key 为cachekey 的值 parmCache[参数化SQL语句]=parameter[]数据组对象
MySqlParameter[] cachedParms = (MySqlParameter[])parmCache[cacheKey];

//如果不存在 则返回为空
if (cachedParms == null)
return null;
//反之 Hashtable表中存在 key为cacheky 的对象则返回 他的 副本 对象 par[]
MySqlParameter[] clonedParms = new MySqlParameter[cachedParms.Length];

for (int i = 0, j = cachedParms.Length; i < j; i++)
clonedParms[i] = (MySqlParameter)((ICloneable)cachedParms[i]).Clone();

return clonedParms;
}
#endregion

#region 执行预定义Command对象[PrepareCommand(...)]
/// <summary>
/// 要执行:预定义Command对象(PrepareCommand)
/// </summary>
/// <param name="cmd">MySqlCommand 对象</param>
/// <param name="conn">MySqlConnection 对象</param>
/// <param name="trans">MySqlTransaction 对象</param>
/// <param name="cmdType">命令类别：存储过程、文本字符串等</param>
/// <param name="cmdText">存储过程名称或SQL命令文本,如：select * from UserTab</param>
/// <param name="cmdParms">Command对象需要使用的参数列表</param>
public static void PrepareCommand(MySqlCommand cmd, MySqlConnection conn, MySqlTransaction trans, CommandType cmdType, string cmdText, MySqlParameter[] cmdParms)
{
try
{
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);
}
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
throw;
}
}
#endregion

#region 提交事务 [TransactionCommit(...)]
/// <summary>
/// 提交事务
/// </summary>
/// <param name="trans">事务</param>
public static void TransactionCommit(MySqlTransaction trans)
{
trans.Commit();
}
#endregion

#region 回滚事务 [TransactionRollback(...)]
/// <summary>
/// 回滚事务
/// </summary>
/// <param name="trans">事务</param>
public static void TransactionRollback(MySqlTransaction trans)
{
trans.Rollback();
}
#endregion
}
}