OracleHelper

using System;
using System.Configuration;
using System.Data;
using System.Data.OracleClient;
using System.Collections;

namespace WMSWebReport.DBUtility {

    /// <summary>
    /// A helper class used to execute queries against an Oracle database
    /// </summary>
    public abstract class OracleHelper {

        // Read the connection strings from the configuration file
        public static readonly string ConnectionString = ConfigurationSettings.AppSettings["DefaultConnetion"];
        

        //Create a hashtable for the parameter cached
        private static Hashtable parmCache = Hashtable.Synchronized(new Hashtable());

        /// <summary>
        /// Execute a database query which does not include a select
        /// </summary>
        /// <param name="connString">Connection string to database</param>
        /// <param name="cmdType">Command type either stored procedure or SQL</param>
        /// <param name="cmdText">Acutall SQL Command</param>
        /// <param name="commandParameters">Parameters to bind to the command</param>
        /// <returns></returns>
        public static int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText, params OracleParameter[] commandParameters) {
            // Create a new Oracle command
            OracleCommand cmd = new OracleCommand();

            //Create a connection
            using (OracleConnection connection = new OracleConnection(connectionString)) {
                 connection.Open();
                //Prepare the command
                PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);

                //Execute the command
                int val = cmd.ExecuteNonQuery();
                cmd.Parameters.Clear();
                return val;
            }
        }

        /// <summary>
        /// Execute an OracleCommand (that returns no resultset) against an existing database transaction 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "PublishOrders", new OracleParameter(":prodid", 24));
        /// </remarks>
        /// <param name="trans">an existing database transaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or PL/SQL command</param>
        /// <param name="commandParameters">an array of OracleParamters used to execute the command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(OracleTransaction trans, CommandType cmdType, string cmdText, params OracleParameter[] commandParameters) {
            OracleCommand cmd = new OracleCommand();
            PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, commandParameters);
            int val = cmd.ExecuteNonQuery();
            cmd.Parameters.Clear();
            return val;
        }

        /// <summary>
        /// Execute an OracleCommand (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 OracleParameter(":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 PL/SQL command</param>
        /// <param name="commandParameters">an array of OracleParamters used to execute the command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(OracleConnection connection, CommandType cmdType, string cmdText, params OracleParameter[] commandParameters) {

            OracleCommand cmd = new OracleCommand();

            PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
            int val = cmd.ExecuteNonQuery();
            cmd.Parameters.Clear();
            return val;
        }


        public static int ExecuteBatchNonQuery(string connection, CommandType cmdType, string[] cmdText, params OracleParameter[] commandParameters)
        {    
            int val = 0;
            OracleCommand cmd = new OracleCommand();

            using (OracleConnection conn = new OracleConnection(connection))
            {
                //    PrepareCommand();
                conn.Open();
                cmd.Connection = conn;
                OracleTransaction tx = conn.BeginTransaction();
                cmd.Transaction = tx;
                try
                {
                    for(int i=0 ;i< cmdText.Length; i++)
                    {
                        cmd.CommandText = cmdText[i];
                        cmd.ExecuteNonQuery();
                    }
                    tx.Commit();
                    val = 1;
                }
                catch(System.Data.OracleClient.OracleException e)
                {
                    tx.Rollback();
                    throw new Exception(e.Message);        
                }    
        
                finally
                {
                    conn.Close();
                }
                return val;
            }
            
        }

        /// <summary>
        /// Execute a select query that will return a result set
        /// </summary>
        /// <param name="connString">Connection string</param>
        //// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or PL/SQL command</param>
        /// <param name="commandParameters">an array of OracleParamters used to execute the command</param>
        /// <returns></returns>
        public static OracleDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params OracleParameter[] commandParameters) {

            //Create the command and connection
            OracleCommand cmd = new OracleCommand();
            OracleConnection conn = new OracleConnection(connectionString);

            try
            {
                //Prepare the command to execute
                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);

                //Execute the query, stating that the connection should close when the resulting datareader has been read
              OracleDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
               // OracleDataReader rdr = cmd.ExecuteReader();
                cmd.Parameters.Clear();
                return rdr;

            }
            catch
            {

                //If an error occurs close the connection as the reader will not be used and we expect it to close the connection
                conn.Close();
                throw;
            }
            finally
            {
                
              // conn.Close();
            
            }
        }

        /// <summary>
        /// Execute an OracleCommand 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 OracleParameter(":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 PL/SQL command</param>
        /// <param name="commandParameters">an array of OracleParamters 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 OracleParameter[] commandParameters) {
            OracleCommand cmd = new OracleCommand();

            using (OracleConnection conn = new OracleConnection(connectionString)) {
                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
                object val = cmd.ExecuteScalar();
                cmd.Parameters.Clear();
                return val;
            }
        }

        ///    <summary>
        ///    Execute    a OracleCommand (that returns a 1x1 resultset)    against    the    specified SqlTransaction
        ///    using the provided parameters.
        ///    </summary>
        ///    <param name="transaction">A    valid SqlTransaction</param>
        ///    <param name="commandType">The CommandType (stored procedure, text, etc.)</param>
        ///    <param name="commandText">The stored procedure name    or PL/SQL command</param>
        ///    <param name="commandParameters">An array of    OracleParamters used to execute the command</param>
        ///    <returns>An    object containing the value    in the 1x1 resultset generated by the command</returns>
        public static object ExecuteScalar(OracleTransaction transaction, CommandType commandType, string commandText, params OracleParameter[] commandParameters) {
            if(transaction == null)
                throw new ArgumentNullException("transaction");
            if(transaction != null && transaction.Connection == null)
                throw new ArgumentException("The transaction was rollbacked    or commited, please    provide    an open    transaction.", "transaction");

            // Create a    command    and    prepare    it for execution
            OracleCommand cmd = new OracleCommand();

            PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);

            // Execute the command & return    the    results
            object retval = cmd.ExecuteScalar();

            // Detach the SqlParameters    from the command object, so    they can be    used again
            cmd.Parameters.Clear();
            return retval;
        }

        /// <summary>
        /// Execute an OracleCommand 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(conn, CommandType.StoredProcedure, "PublishOrders", new OracleParameter(":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 PL/SQL command</param>
        /// <param name="commandParameters">an array of OracleParamters 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(OracleConnection connectionString, CommandType cmdType, string cmdText, params OracleParameter[] commandParameters) {
            OracleCommand cmd = new OracleCommand();

            PrepareCommand(cmd, connectionString, null, cmdType, cmdText, commandParameters);
            object val = cmd.ExecuteScalar();
            cmd.Parameters.Clear();
            return val;
        }

        /// <summary>
        /// Add a set of parameters to the cached
        /// </summary>
        /// <param name="cacheKey">Key value to look up the parameters</param>
        /// <param name="commandParameters">Actual parameters to cached</param>
        public static void CacheParameters(string cacheKey, params OracleParameter[] commandParameters) {
            parmCache[cacheKey] = commandParameters;
        }

        /// <summary>
        /// Fetch parameters from the cache
        /// </summary>
        /// <param name="cacheKey">Key to look up the parameters</param>
        /// <returns></returns>
        public static OracleParameter[] GetCachedParameters(string cacheKey) {
            OracleParameter[] cachedParms = (OracleParameter[])parmCache[cacheKey];

            if (cachedParms == null)
                return null;

            // If the parameters are in the cache
            OracleParameter[] clonedParms = new OracleParameter[cachedParms.Length];

            // return a copy of the parameters
            for (int i = 0, j = cachedParms.Length; i < j; i++)
                clonedParms[i] = (OracleParameter)((ICloneable)cachedParms[i]).Clone();

            return clonedParms;
        }

        /// <summary>
        /// Internal function to prepare a command for execution by the database
        /// </summary>
        /// <param name="cmd">Existing command object</param>
        /// <param name="conn">Database connection object</param>
        /// <param name="trans">Optional transaction object</param>
        /// <param name="cmdType">Command type, e.g. stored procedure</param>
        /// <param name="cmdText">Command test</param>
        /// <param name="commandParameters">Parameters for the command</param>
        private static void PrepareCommand(OracleCommand cmd, OracleConnection conn, OracleTransaction trans, CommandType cmdType, string cmdText, OracleParameter[] commandParameters) {
     
            //Open the connection if required
            if (conn.State != ConnectionState.Open)
                conn.Open();

            //Set up the command
            cmd.Connection = conn;
            cmd.CommandText = cmdText;
            cmd.CommandType = cmdType;

            //Bind it to the transaction if it exists
            if (trans != null)
                cmd.Transaction = trans;

            // Bind the parameters passed in
            if (commandParameters != null) {
                foreach (OracleParameter parm in commandParameters)
                    cmd.Parameters.Add(parm);
            }
        }

        /// <summary>
        /// Converter to use boolean data type with Oracle
        /// </summary>
        /// <param name="value">Value to convert</param>
        /// <returns></returns>
        public static string OraBit(bool value) {
            if(value)
                return "Y";
            else
                return "N";
        }

        /// <summary>
        /// Converter to use boolean data type with Oracle
        /// </summary>
        /// <param name="value">Value to convert</param>
        /// <returns></returns>
        public static bool OraBool(string value) {
            if(value.Equals("Y"))
                return true;
            else
                return false;
        } 
    }
}