using System;
using System.Collections.Generic;
using System.Data;
using System.Data.OracleClient;
using System.Linq;
using System.Web;

namespace WebserviceGS
{
    public class DBorl
    {
        public static string connectionString = "Data Source=(DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 172.17.3.21)(PORT = 1521)))(CONNECT_DATA = (SERVICE_NAME = ORCL)));Persist Security Info=True;User Id = bgmes;Password=bg_mes";

        #region 公用方法

        public static int GetMaxID(string FieldName, string TableName)
        {
            string strsql = "select max(" + FieldName + ")+1 from " + TableName;
            object obj = GetSingle(strsql);
            if (obj == null)
            {
                return 1;
            }
            else
            {
                return int.Parse(obj.ToString());
            }
        }
        public static bool Exists(string strSql)
        {
            object obj = GetSingle(strSql);
            int cmdresult;
            if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
            {
                cmdresult = 0;
            }
            else
            {
                cmdresult = int.Parse(obj.ToString());
            }
            if (cmdresult == 0)
            {
                return false;
            }
            else
            {
                return true;
            }
        }

        public static bool Exists(string strSql, params OracleParameter[] cmdParms)
        {
            object obj = GetSingle(strSql, cmdParms);
            int cmdresult;
            if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
            {
                cmdresult = 0;
            }
            else
            {
                cmdresult = int.Parse(obj.ToString());
            }
            if (cmdresult == 0)
            {
                return false;
            }
            else
            {
                return true;
            }
        }

        #endregion


        /// <summary>
        /// 执行一条计算查询结果语句，返回查询结果（object）。
        /// </summary>
        /// <param name="SQLString">计算查询结果语句</param>
        /// <returns>查询结果（object）</returns>
        public static object GetSingle(string SQLString)
        {
            using (OracleConnection connection = new OracleConnection(connectionString))
            {
                using (OracleCommand cmd = new OracleCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        object obj = cmd.ExecuteScalar();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return null;
                        }
                        else
                        {
                            return obj;
                        }
                    }
                    catch (System.Data.OracleClient.OracleException e)
                    {
                        connection.Close();
                        throw new Exception(e.Message);
                    }
                }
            }
        }

        /// <summary>
        /// 执行一条计算查询结果语句，返回查询结果（object）。
        /// </summary>
        /// <param name="SQLString">计算查询结果语句</param>
        /// <returns>查询结果（object）</returns>
        public static object GetSingle(string SQLString, params OracleParameter[] cmdParms)
        {
            using (OracleConnection connection = new OracleConnection(connectionString))
            {
                using (OracleCommand cmd = new OracleCommand())
                {
                    try
                    {
                        PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                        object obj = cmd.ExecuteScalar();
                        cmd.Parameters.Clear();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return null;
                        }
                        else
                        {
                            return obj;
                        }
                    }
                    catch (System.Data.OracleClient.OracleException e)
                    {
                        throw new Exception(e.Message);
                    }
                }
            }
        }

        private static void PrepareCommand(OracleCommand cmd, OracleConnection conn, OracleTransaction trans, string cmdText, OracleParameter[] cmdParms)
        {
            if (conn.State != ConnectionState.Open)
                conn.Open();
            cmd.Connection = conn;
            cmd.CommandText = cmdText;
            if (trans != null)
                cmd.Transaction = trans;
            cmd.CommandType = CommandType.Text;//cmdType;
            if (cmdParms != null)
            {
                foreach (OracleParameter parm in cmdParms)
                    cmd.Parameters.Add(parm);
            }
        }

        public static int ExecuteSql(string SQLString)
        {
            using (OracleConnection connection = new OracleConnection(connectionString))
            {
                using (OracleCommand cmd = new OracleCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        int rows = cmd.ExecuteNonQuery();
                        return rows;
                    }
                    catch (System.Data.OracleClient.OracleException E)
                    {
                        connection.Close();
                        throw new Exception(E.Message);
                    }
                }
            }
        }

        public static int ExecuteSql(string SQLString,string clob)
        {
            using (OracleConnection connection = new OracleConnection(connectionString))
            {
                using (OracleCommand cmd = new OracleCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        OracleParameter op = new OracleParameter("clob", OracleType.Clob);
                        op.Value = clob;
                        cmd.Parameters.Add(op);
                        int rows = cmd.ExecuteNonQuery();                      
                        return rows;
                    }
                    catch (System.Data.OracleClient.OracleException E)
                    {
                        connection.Close();
                        throw new Exception(E.Message);
                    }
                }
            }
        }
    }
}