using System;
using System.Data;
using System.Data.OleDb;

namespace Hellosea.WebModule.Data
{
	/// <summary>
	/// 数据库的基础类，所有的数据库类均基于该类，为网站的核心程序。
	/// 数据库其它类均派生此类。
	/// </summary>
	public class DbBase
	{
		protected OleDbConnection DbConnection;
		private string mConnectionString;

		/// <summary>
		/// 受保护的只读连接字符串属性
		/// 派生类可以继承该属性
		/// </summary>
		protected string ConnectionString
		{
			get 
			{
				return mConnectionString;
			}
		}

		/// <summary>
		/// 参数化的构造函数，并建立数据库连接
		/// </summary>
		/// <param name="newConnectionString">数据库连接字符串</param>
		public DbBase(string newConnectionString)
		{
			mConnectionString = newConnectionString;
			DbConnection = new OleDbConnection(mConnectionString);
		}

		/// <summary>
		/// 建立一OleDbCommand的原型，这一新的命令通常用于把
		/// SELECT语句的结果返回给DataSet或DataReader。
		/// </summary>
		/// <param name="cmdString">存储过程名</param>
		/// <param name="parameters">IDataParameter类的数组</param>
		/// <returns></returns>
		private OleDbCommand BuildQueryCommand( string cmdString, IDataParameter[] parameters )
		{
			OleDbCommand command = new OleDbCommand( cmdString, DbConnection );

			foreach (OleDbParameter parameter in parameters)
			{
				command.Parameters.Add( parameter );
			}

			return command;
		}

		/// <summary>
		/// 建立一OleDbCommand的原型，这一新的命令通常用于把
		/// SELECT语句的结果返回给DataSet或DataReader。
		/// </summary>
		/// <param name="cmdString">存储过程名</param>
		/// <returns></returns>
		private OleDbCommand BuildQueryCommand( string cmdString )
		{
			OleDbCommand command = new OleDbCommand( cmdString, DbConnection );
			return command;
		}

		/// <summary>
		/// 执行OleDbCommand命令，不返回值
		/// </summary>
		/// <param name="cmdString">执行的SQL语句</param>
		/// <param name="parameters">IDataParameter类的数组</param>
		protected void RunCommand( string cmdString, IDataParameter[] parameters )
		{
			if (DbConnection.State == ConnectionState.Closed) DbConnection.Open();
			OleDbCommand command = BuildQueryCommand( cmdString, parameters );
			command.ExecuteNonQuery();
			DbConnection.Close();
		}

		/// <summary>
		/// 执行OleDbCommand命令，不返回值
		/// </summary>
		/// <param name="cmdString">执行的SQL语句</param>
		protected void RunCommand( string cmdString)
		{
			if (DbConnection.State == ConnectionState.Closed) DbConnection.Open();
			OleDbCommand command = BuildQueryCommand( cmdString );
			command.ExecuteNonQuery();
			DbConnection.Close();
		}

		/// <summary>
		/// 执行查询，并返回OleDbDataReader查询记录
		/// </summary>
		/// <param name="cmdString">执行的SQL语句</param>
		/// <returns>返回OleDbDataReader查询记录</returns>
		protected OleDbDataReader GetDataReader(string cmdString)
		{
			OleDbDataReader returnReader;

			if (DbConnection.State == ConnectionState.Closed) DbConnection.Open();
			OleDbCommand command = BuildQueryCommand( cmdString );

			returnReader = command.ExecuteReader();
			//DbConnection.Close();
			return returnReader;
		}

		/// <summary>
		/// 执行查询，并返回OleDbDataReader查询记录
		/// </summary>
		/// <param name="cmdString">执行的SQL语句</param>
		/// <param name="parameters">IDataParameter类的数组</param>
		/// <returns>返回OleDbDataReader查询记录</returns>
		protected OleDbDataReader GetDataReader(string cmdString, IDataParameter[] parameters )
		{
			OleDbDataReader returnReader;

			if (DbConnection.State == ConnectionState.Closed) DbConnection.Open();
			OleDbCommand command = BuildQueryCommand( cmdString, parameters );

			returnReader = command.ExecuteReader();
			//DbConnection.Close();
			return returnReader;
		}

		/// <summary>
		/// 执行查询，并返回DataSet查询数据集
		/// </summary>
		/// <param name="cmdStringName">执行的SQL语句</param>
		/// <param name="tableName">要填充数据集的表名</param>
		/// <returns>返回DataSet类型数据集</returns>
		protected DataSet GetDataSet(string cmdStringName, string tableName )
		{
			DataSet dataSet = new DataSet();
			if (DbConnection.State == ConnectionState.Closed) DbConnection.Open();
			OleDbDataAdapter oleDA = new OleDbDataAdapter();
			oleDA.SelectCommand = BuildQueryCommand( cmdStringName );
			oleDA.Fill( dataSet, tableName );
			DbConnection.Close();

			return dataSet;
		}

		/// <summary>
		/// 执行查询，并返回DataSet查询数据集
		/// </summary>
		/// <param name="cmdStringName">执行的SQL语句</param>
		/// <param name="parameters">IDataParameter类的数组</param>
		/// <param name="tableName">要填充数据集的表名</param>
		/// <returns>返回DataSet类型数据集</returns>
		protected DataSet GetDataSet(string cmdStringName, IDataParameter[] parameters, string tableName )
		{
			DataSet dataSet = new DataSet();
			if (DbConnection.State == ConnectionState.Closed) DbConnection.Open();
			OleDbDataAdapter oleDA = new OleDbDataAdapter();
			oleDA.SelectCommand = BuildQueryCommand( cmdStringName, parameters );
			oleDA.Fill( dataSet, tableName );
			DbConnection.Close();

			return dataSet;
		}

		/// <summary>
		/// 执行查询，把数据填充至指定数据集中
		/// </summary>
		/// <param name="cmdStringName">执行的SQL语句</param>
		/// <param name="tableName">要填充数据集的表名</param>
		/// <param name="dataSet">填充数据集</param>
		protected void GetDataSet(string cmdStringName, IDataParameter[] parameters, DataSet dataSet, string tableName )
		{
			if (DbConnection.State == ConnectionState.Closed) DbConnection.Open();
			OleDbDataAdapter adapter = new OleDbDataAdapter();
			adapter.SelectCommand = BuildQueryCommand( cmdStringName, parameters );
			adapter.Fill( dataSet, tableName );
			DbConnection.Close();		
		}

		/// <summary>
		/// 关闭数据库
		/// </summary>
		protected void CloseConnection()
		{
			if (DbConnection.State == ConnectionState.Open)
			{
				DbConnection.Close();
			}
		}
	}
}