//这是在网上找的中文解释的SqlHelper
using System;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Collections;
namespace com.DataAccess
{
/**//// <summary>
/// SqlHelper类提供很高的数据访问性能,
/// 使用SqlClient类的通用定义.
/// </summary>
public abstract class SqlHelper
{
//定义数据库连接串
public static readonly string ConnectionStringLocalTransaction = ConfigurationManager.ConnectionStrings["TestConnectionString"].ConnectionString;
//public static readonly string ConnectionStringInventoryDistributedTransaction = ConfigurationManager.ConnectionStrings["SQLConnString2"].ConnectionString;
//public static readonly string ConnectionStringOrderDistributedTransaction = ConfigurationManager.ConnectionStrings["SQLConnString3"].ConnectionString;
//public static readonly string ConnectionStringProfile = ConfigurationManager.ConnectionStrings["SQLProfileConnString"].ConnectionString;
// 存贮Cache缓存的Hashtable集合
private static Hashtable parmCache = Hashtable.Synchronized(new Hashtable());
/**//// <summary>
/// 使用连接字符串，执行一个SqlCommand命令（没有记录返回）
/// 使用提供的参数集.
/// </summary>
/// <remarks>
/// 示例:
/// int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">一个有效的SqlConnection连接串</param>
/// <param name="commandType">命令类型CommandType(stored procedure, text, etc.)</param>
/// <param name="commandText">存贮过程名称或是一个T-SQL语句串</param>
/// <param name="commandParameters">执行命令的参数集</param>
/// <returns>受此命令影响的行数</returns>
public static int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();
using (SqlConnection conn = new SqlConnection(connectionString))
{
PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return val;
}
}
/**//// <summary>
/// 在一个存在的连接上执行数据库的命令操作
/// 使用提供的参数集.
/// </summary>
/// <remarks>
/// e.g.:
/// int result = ExecuteNonQuery(connection, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="conn">一个存在的数据库连接对象</param>
/// <param name="commandType">命令类型CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">存贮过程名称或是一个T-SQL语句串</param>
/// <param name="commandParameters">执行命令的参数集</param>
/// <returns>受此命令影响的行数</returns>
public static int ExecuteNonQuery(SqlConnection connection, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return val;
}
/**//// <summary>
/// 在一个事务的连接上执行数据库的命令操作
/// 使用提供的参数集.
/// </summary>
/// <remarks>
/// e.g.:
/// int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="trans">一个存在的事务</param>
/// <param name="commandType">命令类型CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">存贮过程名称或是一个T-SQL语句串</param>
/// <param name="commandParameters">执行命令的参数集</param>
/// <returns>受此命令影响的行数</returns>
public static int ExecuteNonQuery(SqlTransaction trans, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, commandParameters);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return val;
}
/**//// <summary>
/// 在一个连接串上执行一个命令，返回一个SqlDataReader对象
/// 使用提供的参数.
/// </summary>
/// <remarks>
/// e.g.:
/// SqlDataReader r = ExecuteReader(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">一个有效的SqlConnection连接串</param>
/// <param name="commandType">命令类型CommandType(stored procedure, text, etc.)</param>
/// <param name="commandText">存贮过程名称或是一个T-SQL语句串</param>
/// <param name="commandParameters">执行命令的参数集</param>
/// <returns>一个结果集对象SqlDataReader</returns>
public static SqlDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();
SqlConnection conn = new SqlConnection(connectionString);
// 如果不存在要查询的对象，则发生异常
// 连接要关闭
// CommandBehavior.CloseConnection在异常时不发生作用
try
{
PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
cmd.Parameters.Clear();
return rdr;
}
catch
{
conn.Close();
throw;
}
}
/**//// <summary>
/// 在一个连接串上执行一个命令，返回表中第一行，第一列的值
/// 使用提供的参数.
/// </summary>
/// <remarks>
/// e.g.:
/// Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">一个有效的SqlConnection连接串</param>
/// <param name="commandType">命令类型CommandType(stored procedure, text, etc.)</param>
/// <param name="commandText">存贮过程名称或是一个T-SQL语句串</param>
/// <param name="commandParameters">执行命令的参数集</param> /// <returns>返回的对象，在使用时记得类型转换</returns>
public static object ExecuteScalar(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();
using (SqlConnection connection = new SqlConnection(connectionString))
{
PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
object val = cmd.ExecuteScalar();
cmd.Parameters.Clear();
return val;
}
}
/**//// <summary>
/// 在一个连接上执行一个命令，返回表中第一行，第一列的值
/// 使用提供的参数.
/// </summary>
/// <remarks>
/// e.g.:
/// Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">一个有效的SqlConnection连接</param>
/// <param name="commandType">命令类型CommandType(stored procedure, text, etc.)</param>
/// <param name="commandText">存贮过程名称或是一个T-SQL语句串</param>
/// <param name="commandParameters">执行命令的参数集</param> /// <returns>返回的对象，在使用时记得类型转换</returns>
public static object ExecuteScalar(SqlConnection connection, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
object val = cmd.ExecuteScalar();
cmd.Parameters.Clear();
return val;
}
/**//// <summary>
/// 在缓存中添加参数数组
/// </summary>
/// <param name="cacheKey">参数的Key</param>
/// <param name="cmdParms">参数数组</param>
public static void CacheParameters(string cacheKey, params SqlParameter[] commandParameters)
{
parmCache[cacheKey] = commandParameters;
}
/**//// <summary>
/// 提取缓存的参数数组
/// </summary>
/// <param name="cacheKey">查找缓存的key</param>
/// <returns>返回被缓存的参数数组</returns>
public static SqlParameter[] GetCachedParameters(string cacheKey)
{
SqlParameter[] cachedParms = (SqlParameter[])parmCache[cacheKey];
if (cachedParms == null)
return null;
SqlParameter[] clonedParms = new SqlParameter[cachedParms.Length];
for (int i = 0, j = cachedParms.Length; i < j; i++)
clonedParms[i] = (SqlParameter)((ICloneable)cachedParms[i]).Clone();
return clonedParms;
}
/**//// <summary>
/// 提供一个SqlCommand对象的设置
/// </summary>
/// <param name="cmd">SqlCommand对象</param>
/// <param name="conn">SqlConnection 对象</param>
/// <param name="trans">SqlTransaction 对象</param>
/// <param name="cmdType">CommandType 如存贮过程，T-SQL</param>
/// <param name="cmdText">存贮过程名或查询串</param>
/// <param name="cmdParms">命令中用到的参数集</param>
private static void PrepareCommand(SqlCommand cmd, SqlConnection conn, SqlTransaction trans, CommandType cmdType, string cmdText, SqlParameter[] 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 (SqlParameter parm in cmdParms)
cmd.Parameters.Add(parm);
}
}
}
}
