C#MysqlHelper
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MysqlHelper类
using System;
using System.Collections;
using System.Collections.Specialized;
using System.Data;
using MySql.Data.MySqlClient;
using System.Configuration;
using System.Data.Common;
using System.Collections.Generic;
using System.Text.RegularExpressions;
namespace LOAF.DAL
{
public class MysqlHelper
{
//数据库连接字符串(web.config来配置)，可以动态更改connectionString支持多数据库.
// public static string connectionString = ConfigurationManager.ConnectionStrings["ConnDB"].ConnectionString;
public static string connectionString = ConfigurationManager.AppSettings["MySQL"];
//public string m = ConfigurationManager.AppSettings["MySQL"];
public MysqlHelper() { }
#region ExecuteNonQuery
//执行SQL语句，返回影响的记录数
/// <summary>
/// 执行SQL语句，返回影响的记录数
/// </summary>
/// <param name="SQLString">SQL语句</param>
/// <returns>影响的记录数</returns>
public static int ExecuteNonQuery(string SQLString)
{
using (MySqlConnection connection = new MySqlConnection(connectionString))
{
using (MySqlCommand cmd = new MySqlCommand(SQLString, connection))
{
try
{
connection.Open();
int rows = cmd.ExecuteNonQuery();
return rows;
}
catch (MySql.Data.MySqlClient.MySqlException e)
{
connection.Close();
throw e;
}
}
}
}
/// <summary>
/// 执行SQL语句，返回影响的记录数
/// </summary>
/// <param name="SQLString">SQL语句</param>
/// <returns>影响的记录数</returns>
public static int ExecuteNonQuery(string SQLString, params MySqlParameter[] cmdParms)
{
using (MySqlConnection connection = new MySqlConnection(connectionString))
{
using (MySqlCommand cmd = new MySqlCommand())
{
try
{
PrepareCommand(cmd, connection, null, SQLString, cmdParms);
int rows = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return rows;
}
catch (MySql.Data.MySqlClient.MySqlException e)
{
throw e;
}
}
}
}
//执行多条SQL语句，实现数据库事务。
/// <summary>
/// 执行多条SQL语句，实现数据库事务。
/// </summary>
/// <param name="SQLStringList">多条SQL语句</param>
public static bool ExecuteNoQueryTran(List<String> SQLStringList)
{
using (MySqlConnection conn = new MySqlConnection(connectionString))
{
conn.Open();
MySqlCommand cmd = new MySqlCommand();
cmd.Connection = conn;
MySqlTransaction tx = conn.BeginTransaction();
cmd.Transaction = tx;
try
{
for (int n = 0; n < SQLStringList.Count; n++)
{
string strsql = SQLStringList[n];
if (strsql.Trim().Length > 1)
{
cmd.CommandText = strsql;
PrepareCommand(cmd, conn, tx, strsql, null);
cmd.ExecuteNonQuery();
}
}
cmd.ExecuteNonQuery();
tx.Commit();
return true;
}
catch
{
tx.Rollback();
return false;
}
}
}
#endregion
#region ExecuteScalar
/// <summary>
/// 执行一条计算查询结果语句，返回查询结果（object）。
/// </summary>
/// <param name="SQLString">计算查询结果语句</param>
/// <returns>查询结果（object）</returns>
public static object ExecuteScalar(string SQLString)
{
using (MySqlConnection connection = new MySqlConnection(connectionString))
{
using (MySqlCommand cmd = new MySqlCommand(SQLString, connection))
{
try
{
connection.Open();
object obj = cmd.ExecuteScalar();
if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
{
return null;
}
else
{
return obj;
}
}
catch (MySql.Data.MySqlClient.MySqlException e)
{
connection.Close();
throw e;
}
}
}
}
/// <summary>
/// 执行一条计算查询结果语句，返回查询结果（object）。
/// </summary>
/// <param name="SQLString">计算查询结果语句</param>
/// <returns>查询结果（object）</returns>
public static object ExecuteScalar(string SQLString, params MySqlParameter[] cmdParms)
{
using (MySqlConnection connection = new MySqlConnection(connectionString))
{
using (MySqlCommand cmd = new MySqlCommand())
{
try
{
PrepareCommand(cmd, connection, null, SQLString, cmdParms);
object obj = cmd.ExecuteScalar();
cmd.Parameters.Clear();
if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
{
return null;
}
else
{
return obj;
}
}
catch (MySql.Data.MySqlClient.MySqlException e)
{
throw e;
}
}
}
}
#endregion
#region ExecuteReader
/// <summary>
/// 执行查询语句，返回MySqlDataReader ( 注意：调用该方法后，一定要对MySqlDataReader进行Close )
/// </summary>
/// <param name="strSQL">查询语句</param>
/// <returns>MySqlDataReader</returns>
public static MySqlDataReader ExecuteReader(string strSQL)
{
MySqlConnection connection = new MySqlConnection(connectionString);
MySqlCommand cmd = new MySqlCommand(strSQL, connection);
try
{
connection.Open();
MySqlDataReader myReader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
return myReader;
}
catch (MySql.Data.MySqlClient.MySqlException e)
{
throw e;
}
}
/// <summary>
/// 执行查询语句，返回MySqlDataReader ( 注意：调用该方法后，一定要对MySqlDataReader进行Close )
/// </summary>
/// <param name="strSQL">查询语句</param>
/// <returns>MySqlDataReader</returns>
public static MySqlDataReader ExecuteReader(string SQLString, params MySqlParameter[] cmdParms)
{
MySqlConnection connection = new MySqlConnection(connectionString);
MySqlCommand cmd = new MySqlCommand();
try
{
PrepareCommand(cmd, connection, null, SQLString, cmdParms);
MySqlDataReader myReader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
cmd.Parameters.Clear();
return myReader;
}
catch (MySql.Data.MySqlClient.MySqlException e)
{
throw e;
}
// finally
// {
// cmd.Dispose();
// connection.Close();
// }
}
#endregion
#region ExecuteDataTable
/// <summary>
/// 执行查询语句，返回DataTable
/// </summary>
/// <param name="SQLString">查询语句</param>
/// <returns>DataTable</returns>
public static DataTable ExecuteDataTable(string SQLString)
{
using (MySqlConnection connection = new MySqlConnection(connectionString))
{
DataSet ds = new DataSet();
try
{
connection.Open();
MySqlDataAdapter command = new MySqlDataAdapter(SQLString, connection);
command.Fill(ds, "ds");
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
throw new Exception(ex.Message);
}
return ds.Tables[0];
}
}
/// <summary>
/// 执行查询语句，返回DataSet
/// </summary>
/// <param name="SQLString">查询语句</param>
/// <returns>DataTable</returns>
public static DataTable ExecuteDataTable(string SQLString, params MySqlParameter[] cmdParms)
{
using (MySqlConnection connection = new MySqlConnection(connectionString))
{
MySqlCommand cmd = new MySqlCommand();
PrepareCommand(cmd, connection, null, SQLString, cmdParms);
using (MySqlDataAdapter da = new MySqlDataAdapter(cmd))
{
DataSet ds = new DataSet();
try
{
da.Fill(ds, "ds");
cmd.Parameters.Clear();
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
throw new Exception(ex.Message);
}
return ds.Tables[0];
}
}
}
//获取起始页码和结束页码
public static DataTable ExecuteDataTable(string cmdText, int startResord, int maxRecord)
{
using (MySqlConnection connection = new MySqlConnection(connectionString))
{
DataSet ds = new DataSet();
try
{
connection.Open();
MySqlDataAdapter command = new MySqlDataAdapter(cmdText, connection);
command.Fill(ds, startResord, maxRecord, "ds");
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
throw new Exception(ex.Message);
}
return ds.Tables[0];
}
}
#endregion
/// <summary>
/// 获取分页数据 在不用存储过程情况下
/// </summary>
/// <param name="recordCount">总记录条数</param>
/// <param name="selectList">选择的列逗号隔开,支持top num</param>
/// <param name="tableName">表名字</param>
/// <param name="whereStr">条件字符 必须前加 and</param>
/// <param name="orderExpression">排序 例如 ID</param>
/// <param name="pageIdex">当前索引页</param>
/// <param name="pageSize">每页记录数</param>
/// <returns></returns>
public static DataTable getPager(out int recordCount, string selectList, string tableName, string whereStr, string orderExpression, int pageIdex, int pageSize)
{
int rows = 0;
DataTable dt = new DataTable();
MatchCollection matchs = Regex.Matches(selectList, @"top\s+\d{1,}", RegexOptions.IgnoreCase);//含有top
string sqlStr = sqlStr = string.Format("select {0} from {1} where 1=1 {2}", selectList, tableName, whereStr);
if (!string.IsNullOrEmpty(orderExpression)) { sqlStr += string.Format(" Order by {0}", orderExpression); }
if (matchs.Count > 0) //含有top的时候
{
DataTable dtTemp = ExecuteDataTable(sqlStr);
rows = dtTemp.Rows.Count;
}
else //不含有top的时候
{
string sqlCount = string.Format("select count(*) from {0} where 1=1 {1} ", tableName, whereStr);
//获取行数
object obj = ExecuteScalar(sqlCount);
if (obj != null)
{
rows = Convert.ToInt32(obj);
}
}
dt = ExecuteDataTable(sqlStr, (pageIdex-1)*pageSize, pageSize);
recordCount = rows;
return dt;
}
#region 创建command
private static void PrepareCommand(MySqlCommand cmd, MySqlConnection conn, MySqlTransaction trans, 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 = CommandType.Text;//cmdType;
if (cmdParms != null)
{
foreach (MySqlParameter parameter in cmdParms)
{
if ((parameter.Direction == ParameterDirection.InputOutput || parameter.Direction == ParameterDirection.Input) &&
(parameter.Value == null))
{
parameter.Value = DBNull.Value;
}
cmd.Parameters.Add(parameter);
}
}
}
#endregion
}
}
需要注意的地方有如下几点
1）在sqlserver中参数化sql语句是用“@”符号，在mysql里面需要是用？号，切记，切记.
2 ）还有就是sqlserver中删除表可以这样写delete news where ID=12，但是在mysql里面 是delete from news where ID=12，收了from报错
3 ）我在使用过程中遇到了中文乱码，网上大部分解决办法是把表的设置成utf-8字符集。以及 C:\Program Files\MySQL\MySQL Server 5.1路径下my.ini 打开找到两处
default-character-set 都设置成=utf8。