using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Collections;
using System.Data.OleDb;
using System.ComponentModel;
using System.Windows.Forms;
namespace CRVM.Utility
{
    /// <summary>
    /// 用于操作DB2数据库的类
    /// </summary>
    public class DB2DBUtility
    {
        private static DB2DBUtility dbInstance;
        //public static string db2ConnectionString = "Provider=IBMDADB2.DB2COPY1;Data Source=COLD2010;User ID=prdb;Location=10.25.26.202;pwd=prdbprdb";
        public static string connectionString = "Provider=IBMDADB2;";

        //OleDbCommand cmd;
        //OleDbConnection conn;

        private DB2DBUtility()
        {
            connectionString =connectionString+ SettingConnectionString();
        }

        public static DB2DBUtility Instance
        {
            get
            {
                if (dbInstance == null)
                    dbInstance = new DB2DBUtility();
                return dbInstance;
            }
        }
        /// <summary>
        /// Make connection string for open database
        /// </summary>
        /// <returns>connection string</returns>
        private string SettingConnectionString()
        {
            //string path = Application.StartupPath + "\\app\\form\\hmisetting.xml";
            string dataconn = "";
            //const string dataConf = "数据库配置";
            //EntityConfigItem database = ConfigHelper.GetInstance(path).GetConfigItemData(dataConf, "database");
            //EntityConfigItem userid = ConfigHelper.GetInstance(path).GetConfigItemData(dataConf, "userid");
            //EntityConfigItem password = ConfigHelper.GetInstance(path).GetConfigItemData(dataConf, "password");
            //EntityConfigItem ip = ConfigHelper.GetInstance(path).GetConfigItemData(dataConf, "ip");
            //dataconn = "Data Source=" + database.Values + ";User ID=" + userid.Values + ";Location=" + ip.Values + ";pwd=" + password.Values;
            return dataconn;
        }

        private 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 int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            // Create a new Oracle command
            OleDbCommand cmd = new OleDbCommand();
            //Create a connection
            using (OleDbConnection connection = new OleDbConnection(connectionString))
            {
                //Prepare the command
                PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
                //Execute the command
                int val = cmd.ExecuteNonQuery();
                cmd.Parameters.Clear();
                try
                {
                    connection.Close();
                }
                catch
                { }
                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 int ExecuteNonQuery(OleDbTransaction trans, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            OleDbCommand cmd = new OleDbCommand();
            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 int ExecuteNonQuery(OleDbConnection connection, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            try
            {
                OleDbCommand cmd = new OleDbCommand();
                PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
                int val = cmd.ExecuteNonQuery();
                cmd.Parameters.Clear();
                return val;
            }
            catch
            {
                throw;
            }
            finally
            {
                connection.Close();
            }
        }
        /// <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 OleDbDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            OleDbCommand cmd = new OleDbCommand();
            //Create the command and connection
            OleDbConnection conn = new OleDbConnection(connectionString);
            try
            {
                //Prepare the command to execute
                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
                // PrepareCommand(cmd, oraconn, null, cmdType, cmdText, commandParameters);
                //Execute the query, stating that the connection should close when the resulting datareader has been read
             
                OleDbDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);

                //OracleDataReader rdr = cmd.ExecuteReader(); //xcs,2009-07-27
                cmd.Parameters.Clear();
                return rdr;
            }
            catch
            {
                conn.Close();
                //If an error occurs close the connection as the reader will not be used and we expect it to close the connection
                throw;
            }
        }
        /// <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 object ExecuteScalar(string connectionString, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            OleDbCommand cmd = new OleDbCommand();
            using (OleDbConnection conn = new OleDbConnection(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 object ExecuteScalar(OleDbTransaction transaction, CommandType commandType, string commandText, params OleDbParameter[] 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
            OleDbCommand cmd = new OleDbCommand();
            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 object ExecuteScalar(OleDbConnection connectionString, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            try
            {
                OleDbCommand cmd = new OleDbCommand();
                PrepareCommand(cmd, connectionString, null, cmdType, cmdText, commandParameters);
                object val = cmd.ExecuteScalar();
                cmd.Parameters.Clear();
                return val;
            }
            catch
            {
                //If an error occurs close the connection as the reader will not be used and we expect it to close the connection
                throw;
            }
            finally
            {
                connectionString.Close();
            }
        }

        /// <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 void CacheParameters(string cacheKey, params OleDbParameter[] commandParameters)
        {
            parmCache[cacheKey] = commandParameters;
        }

        public OleDbParameter[] GetCachedParameters(string cacheKey)
        {
            OleDbParameter[] cachedParms = (OleDbParameter[])parmCache[cacheKey];
            if (cachedParms == null)
                return null;
            // If the parameters are in the cache
            OleDbParameter[] clonedParms = new OleDbParameter[cachedParms.Length];
            // return a copy of the parameters
            for (int i = 0, j = cachedParms.Length; i < j; i++)
                clonedParms[i] = (OleDbParameter)((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 void PrepareCommand(OleDbCommand cmd, OleDbConnection conn, OleDbTransaction trans, CommandType cmdType, string cmdText, OleDbParameter[] commandParameters)
        {
            //Open the connection if required
            if (conn == null)
                conn = new OleDbConnection(connectionString);
            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 (OleDbParameter parm in commandParameters)
                    cmd.Parameters.Add(parm);
            }
        }
    }
}