SQLHelper.cs 文件

SQLHelper.cs 文件




//=================================================================================================


// This file is based on the Microsoft Data Access Application Block for .NET


// For more information please go to http://msdn.microsoft.com/library/en-us/dnbda/html/daab-rm.asp

//=================================================================================================




using System;


using System.Configuration;


using System.Data;


using System.Data.SqlClient;


using System.Collections;






namespace PetShop.DBUtility ......{






/**//**//**//// 〈summary〉


/// The SqlHelper class is intended to encapsulate high performance,


/// scalable best practices for common uses of SqlClient.


/// 〈/summary〉




public abstract class SqlHelper ......{




//Database connection strings


public static readonly string ConnectionStringLocalTransaction = ConfigurationManager.ConnectionStrings[“SQLConnString1“].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;




// Hashtable to store cached parameters


private static Hashtable parmCache = Hashtable.Synchronized(new Hashtable());






/**//**//**//// 〈summary〉


/// Execute a SqlCommand (that returns no resultset) against the database specified in the connection string


/// using the provided parameters.


/// 〈/summary〉


/// 〈remarks〉


/// e.g.:


/// int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, “PublishOrders“, new SqlParameter(“@prodid“, 24));


/// 〈/remarks〉


/// 〈param name=“connectionString“〉a valid connection string for a SqlConnection〈/param〉


/// 〈param name=“commandType“〉the CommandType (stored procedure, text, etc.)〈/param〉


/// 〈param name=“commandText“〉the stored procedure name or T-SQL command〈/param〉


/// 〈param name=“commandParameters“〉an array of SqlParamters used to execute the command〈/param〉


/// 〈returns〉an int representing the number of rows affected by the command〈/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〉


/// Execute a SqlCommand (that returns no resultset) against an existing database connection


/// using the provided parameters.


/// 〈/summary〉


/// 〈remarks〉


/// e.g.:


/// int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, “PublishOrders“, new SqlParameter(“@prodid“, 24));


/// 〈/remarks〉


/// 〈param name=“conn“〉an existing database connection〈/param〉


/// 〈param name=“commandType“〉the CommandType (stored procedure, text, etc.)〈/param〉


/// 〈param name=“commandText“〉the stored procedure name or T-SQL command〈/param〉


/// 〈param name=“commandParameters“〉an array of SqlParamters used to execute the command〈/param〉


/// 〈returns〉an int representing the number of rows affected by the command〈/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〉


/// Execute a SqlCommand (that returns no resultset) using an existing SQL Transaction


/// using the provided parameters.


/// 〈/summary〉


/// 〈remarks〉


/// e.g.:


/// int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, “PublishOrders“, new SqlParameter(“@prodid“, 24));


/// 〈/remarks〉


/// 〈param name=“trans“〉an existing sql transaction〈/param〉


/// 〈param name=“commandType“〉the CommandType (stored procedure, text, etc.)〈/param〉


/// 〈param name=“commandText“〉the stored procedure name or T-SQL command〈/param〉


/// 〈param name=“commandParameters“〉an array of SqlParamters used to execute the command〈/param〉


/// 〈returns〉an int representing the number of rows affected by the command〈/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〉


/// Execute a SqlCommand that returns a resultset against the database specified in the connection string


/// using the provided parameters.


/// 〈/summary〉


/// 〈remarks〉


/// e.g.:


/// SqlDataReader r = ExecuteReader(connString, CommandType.StoredProcedure, “PublishOrders“, new SqlParameter(“@prodid“, 24));


/// 〈/remarks〉


/// 〈param name=“connectionString“〉a valid connection string for a SqlConnection〈/param〉


/// 〈param name=“commandType“〉the CommandType (stored procedure, text, etc.)〈/param〉


/// 〈param name=“commandText“〉the stored procedure name or T-SQL command〈/param〉


/// 〈param name=“commandParameters“〉an array of SqlParamters used to execute the command〈/param〉


/// 〈returns〉A SqlDataReader containing the results〈/returns〉




public static SqlDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) ......{


SqlCommand cmd = new SqlCommand();


SqlConnection conn = new SqlConnection(connectionString);




// we use a try/catch here because if the method throws an exception we want to


// close the connection throw code, because no datareader will exist, hence the


// commandBehaviour.CloseConnection will not work




try ......{


PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);


SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);


cmd.Parameters.Clear();


return rdr;


}




catch ......{


conn.Close();


throw;


}


}






/**//**//**//// 〈summary〉


/// Execute a SqlCommand that returns the first column of the first record against the database specified in the connection string


/// using the provided parameters.


/// 〈/summary〉


/// 〈remarks〉


/// e.g.:


/// Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, “PublishOrders“, new SqlParameter(“@prodid“, 24));


/// 〈/remarks〉


/// 〈param name=“connectionString“〉a valid connection string for a SqlConnection〈/param〉


/// 〈param name=“commandType“〉the CommandType (stored procedure, text, etc.)〈/param〉


/// 〈param name=“commandText“〉the stored procedure name or T-SQL command〈/param〉


/// 〈param name=“commandParameters“〉an array of SqlParamters used to execute the command〈/param〉


/// 〈returns〉An object that should be converted to the expected type using Convert.To{Type}〈/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〉


/// Execute a SqlCommand that returns the first column of the first record against an existing database connection


/// using the provided parameters.


/// 〈/summary〉


/// 〈remarks〉


/// e.g.:


/// Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, “PublishOrders“, new SqlParameter(“@prodid“, 24));


/// 〈/remarks〉


/// 〈param name=“conn“〉an existing database connection〈/param〉


/// 〈param name=“commandType“〉the CommandType (stored procedure, text, etc.)〈/param〉


/// 〈param name=“commandText“〉the stored procedure name or T-SQL command〈/param〉


/// 〈param name=“commandParameters“〉an array of SqlParamters used to execute the command〈/param〉


/// 〈returns〉An object that should be converted to the expected type using Convert.To{Type}〈/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〉


/// add parameter array to the cache


/// 〈/summary〉


/// 〈param name=“cacheKey“〉Key to the parameter cache〈/param〉


/// 〈param name=“cmdParms“〉an array of SqlParamters to be cached〈/param〉




public static void CacheParameters(string cacheKey, params SqlParameter[] commandParameters) ......{


parmCache[cacheKey] = commandParameters;


}






/**//**//**//// 〈summary〉


/// Retrieve cached parameters


/// 〈/summary〉


/// 〈param name=“cacheKey“〉key used to lookup parameters〈/param〉


/// 〈returns〉Cached SqlParamters array〈/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〉


/// Prepare a command for execution


/// 〈/summary〉


/// 〈param name=“cmd“〉SqlCommand object〈/param〉


/// 〈param name=“conn“〉SqlConnection object〈/param〉


/// 〈param name=“trans“〉SqlTransaction object〈/param〉


/// 〈param name=“cmdType“〉Cmd type e.g. stored procedure or text〈/param〉


/// 〈param name=“cmdText“〉Command text, e.g. Select * from Products〈/param〉


/// 〈param name=“cmdParms“〉SqlParameters to use in the command〈/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);


}


}


}


}