用C#实现的数据库抽象工厂(三)

以下是在应用时真正要调用到的类：

(6)DbAccess.cs

using System;
using System.Data;

namespace DbService
{
/// <summary>
/// DbAccess类,即进行数据库访问时需要调用的类
/// </summary>
public class DbAccess
{
/// <summary>
/// DbAccess构造函数
/// </summary>
public DbAccess()
{
}

/// <summary>
/// 无条件查询操作,即查询表中所有记录
/// </summary>
/// <param name="strTableName">表名</param>
/// <param name="strColumn">列名组</param>
/// <returns>无条件查询结果</returns>
public static DataSet SelectAll(string strTableName, string[] strColumn)
{
DataSet ds = new DataSet();
Factory factory = Factory.GetInstance();
AbstractDbFactory abstractDbFactory = factory.CreateInstance();
IDbConnection concreteDbConn = abstractDbFactory.CreateConnection();
concreteDbConn.ConnectionString = abstractDbFactory.GetConnectionString();
concreteDbConn.Open();
IDbCommand concreteDbCommand = abstractDbFactory.CreateCommand();
IDbTransaction concreteDbTrans = abstractDbFactory.CreateTransaction(concreteDbConn);
concreteDbCommand.Connection = concreteDbConn;
concreteDbCommand.Transaction = concreteDbTrans;
IDbDataAdapter concreteDbAdapter = abstractDbFactory.CreateDataAdapter();
try
{
string strSql = "SELECT ";
for(int i = 0; i < strColumn.Length - 1; i++)
{
strSql += (strColumn[i] + ", ");
}
strSql += (strColumn[strColumn.Length - 1] + " FROM " + strTableName);
concreteDbCommand.CommandText = strSql;
concreteDbAdapter.SelectCommand = concreteDbCommand;
concreteDbAdapter.Fill(ds);
concreteDbTrans.Commit();
}
catch
{
concreteDbTrans.Rollback();
ds.Clear();
throw;
}
finally
{
concreteDbConn.Close();
}
return ds;
}

/// <summary>
/// 条件查询操作
/// </summary>
/// <param name="strTableName">表名</param>
/// <param name="strColumn">列名组</param>
/// <param name="strCondition">条件</param>
/// <returns>条件查询结果</returns>
public static DataSet Select(string strTableName, string[] strColumn, string strCondition)
{
DataSet ds = new DataSet();
Factory factory = Factory.GetInstance();
AbstractDbFactory abstractDbFactory = factory.CreateInstance();
IDbConnection concreteDbConn = abstractDbFactory.CreateConnection();
concreteDbConn.ConnectionString = abstractDbFactory.GetConnectionString();
concreteDbConn.Open();
IDbCommand concreteDbCommand = abstractDbFactory.CreateCommand();
IDbTransaction concreteDbTrans = abstractDbFactory.CreateTransaction(concreteDbConn);
concreteDbCommand.Connection = concreteDbConn;
concreteDbCommand.Transaction = concreteDbTrans;
IDbDataAdapter concreteDbAdapter = abstractDbFactory.CreateDataAdapter();
try
{
string strSql = "SELECT ";
for(int i = 0; i < strColumn.Length - 1; i++)
{
strSql += (strColumn[i] + ", ");
}
strSql += (strColumn[strColumn.Length - 1] + " FROM " + strTableName + " WHERE " + strCondition);
concreteDbCommand.CommandText = strSql;
concreteDbAdapter.SelectCommand = concreteDbCommand;
concreteDbAdapter.Fill(ds);
concreteDbTrans.Commit();
}
catch
{
concreteDbTrans.Rollback();
ds.Clear();
throw;
}
finally
{
concreteDbConn.Close();
}
return ds;
}

/// <summary