public enum DBType
  {
    SQLServer = 1,
    MySQL = 2, 
    OleDb = 3,
    Oracle = 4,
    SQLite = 5,
  }

IDbObject db=DBOMaker.CreateDbObj(DBType.SQLServer, "连接字符串");

IDbObject db = DBOMaker.CreateDbObj(DBType.SQLServer, AppSettings.COMMONSETTINGS.DbConfig);
var model = db.QueryModel<Demo1>(
    "select * from DB_Test.dbo.td_test where taskname=" + db.GetParameterName("taskname"),
    new { taskname = taskname });

[TableName("DB_Test.dbo.td_test")]
public class Demo1
{
    public string Guid { get; set; }
    public DateTime? UpdatedDay { get; set; }
    [PrimaryKey]
    public string TaskName { get; set; }
    public int? TimeUsed { get; set; }
    public DateTime UpdateTime { get; set; }
    public bool Status { get; set; }
    public string CurrentKeyWord { get; set; }
    public int? CurrentPage { get; set; }


}

IDbObject db = DBOMaker.CreateDbObj(DBType.SQLServer, dbconn);
var table =db.QueryDataTable(
        "SELECT * FROM dbo.SysObjects WHERE ID = object_id(N'[" + GetTableName(tablename) + "]') AND OBJECTPROPERTY(ID, 'IsTable') = 1");

/// <summary>
/// 查询
/// </summary>
/// <param name="SQLString">sql语句</param>
/// <param name="parameters">参数</param>
/// <returns></returns>
DataSet Query(string SQLString, object parameters=null);

/// <summary>
/// 使用DataReader查询
/// </summary>
/// <param name="sql">Sql语句</param>
/// <param name="parameters">参数</param>
/// <returns></returns>
IDataReader QueryDataReader(string sql, object parameters=null);

/// <summary>
/// 分页查询
/// </summary>
/// <param name="sqlstr">查询语句</param>
/// <param name="pageNo">页码</param>
/// <param name="pageSize">页面大小</param>
/// <param name="orderby">排序字段</param>
/// <param name="select">选择的字段</param>
/// <param name="parameters">参数</param>
/// <returns></returns>
DataTable QueryPageTable(string sqlstr, int pageNo, int pageSize, string orderby, string select,
    object parameters=null);

/// <summary>
/// 分页查询
/// </summary>
/// <param name="sqlstr">sql语句</param>
/// <param name="pageNo">页码</param>
/// <param name="pageSize">页面大小</param>
/// <param name="orderby">排序</param>
/// <param name="direction">排序方向</param>
/// <param name="select">选择的字段</param>
/// <param name="parameters">参数</param>
/// <returns></returns>
DataTable QueryPageTable(string sqlstr, int pageNo, int pageSize, string orderby, OrderDirection direction, string select,
    object parameters=null);

/// <summary>
/// 分页查询 并返回总记录数量
/// </summary>
/// <param name="sqlstr">SQL语句</param>
/// <param name="pageNo">页码</param>
/// <param name="pageSize">分页大小</param>
/// <param name="count">总记录数量</param>
/// <param name="orderby">排序字段</param>
/// <param name="select">选择的字段</param>
/// <param name="parameters">参数</param>
/// <returns></returns>
DataTable QueryPageTable(string sqlstr, int pageNo, int pageSize, out int count, string orderby, string select, object parameters=null);

/// <summary>
/// 分页查询 并返回总记录数量
/// </summary>
/// <param name="sqlstr">sql</param>
/// <param name="pageNo">页码</param>
/// <param name="pageSize">分页大小</param>
/// <param name="count">总记录数量</param>
/// <param name="orderby">排序字段</param>
/// <param name="direction">排序方向</param>
/// <param name="select">选择的字段</param>
/// <param name="parameters">参数</param>
/// <returns></returns>
DataTable QueryPageTable(string sqlstr, int pageNo, int pageSize, out int count, string orderby, OrderDirection direction, string select, object parameters=null);

/// <summary>
/// 查询
/// </summary>
/// <typeparam name="T">模型类型</typeparam>
/// <param name="sql">sql语句</param>
/// <param name="parameters">参数</param>
/// <returns></returns>
T QueryModel<T>(string sql, object parameters=null) where T : class, new();

/// <summary>
/// 查询
/// </summary>
/// <typeparam name="T">模型类型</typeparam>
/// <param name="sql">sql语句</param>
/// <param name="parameters">参数</param>
/// <returns></returns>
List<T> QueryModels<T>(string sql, object parameters=null) where T : class, new();