学步园

首先在工程中引用各种数据库组件.
包括:SqlServer,OleDb,Oracle,ODBC.
调用方法很简单,在创建该类的实例对象时初始化connectionstring数据库连接字符串即可.
该类提供了几种初始化重载方法,可以直接将连接字符串传入,或者通过web.config配置文件ConnectionStrings["connectionstring"].可以直接指明数据库类型,也可以不指明(该类有自动分析功能).
该类代码如下:

using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Configuration;
using System.Data.Common;
using System.Data.SqlClient;
using System.Data.OleDb;
using System.Data.Odbc;
using System.Data.OracleClient;
using System.IO;

namespace BinaryIntellect.DataAccess
{
    public class DatabaseHelper:IDisposable
    {
        private string strConnectionString;
        private DbConnection objConnection;
        private DbCommand objCommand;
        private DbProviderFactory objFactory = null;
        private bool boolHandleErrors;
        private string strLastError;
        private bool boolLogError;
        private string strLogFile;

        public DatabaseHelper(string connectionstring,Providers provider)
        {
            strConnectionString = connectionstring;
            switch (provider)
            {
                case Providers.SqlServer:
                    objFactory = SqlClientFactory.Instance;
                    break;
                case Providers.OleDb:
                    objFactory = OleDbFactory.Instance;
                    break;
                case Providers.Oracle:
                    objFactory = OracleClientFactory.Instance;
                    break;
                case Providers.ODBC:
                    objFactory = OdbcFactory.Instance;
                    break;
                case Providers.ConfigDefined:
                    string providername=ConfigurationManager.ConnectionStrings["connectionstring"].ProviderName;
                    switch (providername)
                    {
                        case "System.Data.SqlClient":
                            objFactory = SqlClientFactory.Instance;
                            break;
                        case "System.Data.OleDb":
                            objFactory = OleDbFactory.Instance;
                            break;
                        case "System.Data.OracleClient":
                            objFactory = OracleClientFactory.Instance;
                            break;
                        case "System.Data.Odbc":
                            objFactory = OdbcFactory.Instance;
                            break;
                    }
                    break;

            }
            objConnection = objFactory.CreateConnection();
            objCommand = objFactory.CreateCommand();

            objConnection.ConnectionString = strConnectionString;
            objCommand.Connection = objConnection;
        }

        public DatabaseHelper(Providers provider):this(ConfigurationManager.ConnectionStrings["connectionstring"].ConnectionString,provider)
        {
        }

        public DatabaseHelper(string connectionstring): this(connectionstring, Providers.SqlServer)
        {
        }

        public DatabaseHelper():this(ConfigurationManager.ConnectionStrings["connectionstring"].ConnectionString,Providers.ConfigDefined)
        {
        }

        public bool HandleErrors
        {
            get
            {
                return boolHandleErrors;
            }
            set
            {
                boolHandleErrors = value;
            }
        }

        public string LastError
        {
            get
            {
                return strLastError;
            }
        }

        public bool LogErrors
        {
            get
            {
                return boolLogError;
            }
            set
            {
                boolLogError=value;
            }
        }

        public string LogFile
        {
            get
            {
                return strLogFile;
            }
            set
            {
                strLogFile = value;
            }
        }

        public int AddParameter(string name,object value)
        {
            DbParameter p = objFactory.CreateParameter();
            p.ParameterName = name;
            p.Value=value;
            return objCommand.Parameters.Add(p);
        }

        public int AddParameter(DbParameter parameter)
        {
            return objCommand.Parameters.Add(parameter);
        }

        public DbCommand Command
        {
            get
            {
                return objCommand;
            }
        }

        public void BeginTransaction()
        {
            if (objConnection.State == System.Data.ConnectionState.Closed)
            {
                objConnection.Open();
            }
            objCommand.Transaction = objConnection.BeginTransaction();
        }

        public void CommitTransaction()
        {
            objCommand.Transaction.Commit();
            objConnection.Close();
        }

        public void RollbackTransaction()
        {
            objCommand.Transaction.Rollback();
            objConnection.Close();
        }

        public int ExecuteNonQuery(string query)
        {
            return ExecuteNonQuery(query, CommandType.Text, ConnectionState.CloseOnExit);
        }

        public int ExecuteNonQuery(string query,CommandType commandtype)
        {
            return ExecuteNonQuery(query, commandtype, ConnectionState.CloseOnExit);
        }

        public int ExecuteNonQuery(string query,ConnectionState connectionstate)
        {
            return ExecuteNonQuery(query,CommandType.Text,connectionstate);
        }

        public int ExecuteNonQuery(string query,CommandType commandtype, ConnectionState connectionstate)
        {
            objCommand.CommandText = query;
            objCommand.CommandType = commandtype;
            int i=-1;
            try
            {
                if (objConnection.State == System.Data.ConnectionState.Closed)
                {
                    objConnection.Open();
                }
                i = objCommand.ExecuteNonQuery();
            }
            catch (Exception ex)
            {
                HandleExceptions(ex);
            }
            finally
            {
                objCommand.Parameters.Clear();
                if (connectionstate == ConnectionState.CloseOnExit)
                {
                    objConnection.Close();
                }
            }

            return i;
        }

        public object ExecuteScalar(