SQLHelper

using System;

using System.Configuration;

using System.Data;

using System.Data.SqlClient;

using System.Collections;



namespace Maticsoft.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.AppSettings["SQLConnString1"];

        public static readonly string ConnectionStringInventoryDistributedTransaction =  ConfigurationManager.AppSettings["SQLConnString2"];

        public static readonly string ConnectionStringOrderDistributedTransaction =  ConfigurationManager.AppSettings["SQLConnString3"];

        public static readonly string ConnectionStringProfile =  ConfigurationManager.AppSettings["SQLProfileConnString"];



        // 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);

            }

        }

    }

}

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