问Entity Framework4.0中域模型与数据库模式的区别

EN

    /// <summary>
    /// A generic repository for working with data in the database
    /// </summary>
    /// <typeparam name="T">A POCO that represents an Entity Framework entity</typeparam>
    public class DataRepository<T> : IDisposable, IRepository<T> where T : class
    {
        /// <summary>
        /// The context object for the database
        /// </summary>
        private ObjectContext _context;

        /// <summary>
        /// The IObjectSet that represents the current entity. Used to query, add, modify and delete objects of the specified entity.
        /// </summary>
        private IObjectSet<T> _objectSet;

        /// <summary>
        /// Initializes a new instance of the DataRepository class
        /// </summary>
        public DataRepository()
            : this(new AdventureWorksEntities())
        {
        }

        /// <summary>
        /// Initializes a new instance of the DataRepository class
        /// </summary>
        /// <param name="context">The Entity Framework ObjectContext</param>
        public DataRepository(ObjectContext context)
        {
            _context = context;
            _objectSet = _context.CreateObjectSet<T>();
        }

        /// <summary>
        /// Gets all records as an IQueryable
        /// </summary>
        /// <returns>An IQueryable object, containing the results of the query</returns>
        public IQueryable<T> GetQuery()
        {
            return from x in _objectSet select x;
        }

        /// <summary>
        /// Releases all resources used by the WarrantManagement.DataExtract.Dal.ReportDataBase
        /// </summary>
        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        /// <summary>
        /// Releases all resources used by the WarrantManagement.DataExtract.Dal.ReportDataBase
        /// </summary>
        /// <param name="disposing">A boolean value indicating whether or not to dispose managed resources</param>
        protected virtual void Dispose(bool disposing)
        {
            if (disposing)
            {
                if (_context != null)
                {
                    _context.Dispose();
                    _context = null;
                }
            }
        }
    }

        using (DataRepository repository = new DataRepository())
        {
            this.GridView1.DataSource = from x in repository.GetQuery()
                                        select new
                                        {
                                            x.MaritalStatus,
                                            x.Contact.FirstName,
                                            x.Contact.LastName,
                                            x.BirthDate
                                        };
            this.GridView1.DataBind();
        }