[Design Patterns]Repository Pattern

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應用程式隨著雲端發展、分散式架構和資料庫的多樣性，資料來源不會只有一種，
為了整合這麼多種資料儲存類型，可以使用Repository Pattern 來切割DAL和BLL

好處

  • BLL不直接存取資料，關注點分離
  • 方便抽換DAL
  • 方便單元測試

先定義Model

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namespace WebApp.Domain.Model
{
    public class MemberInfo
    {
        public int MemberID { get; set; }

        public string NickName { get; set; }

        public string Email { get; set; }
    }
}

建立介面

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namespace WebApp.Domain.Repository
{
    public interface IMemberInfoRepository
    {
        Tuple<Exception, MemberInfo> GetMemberInfo();
    }
}

建立實體

  • MSSQL版本
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namespace WebApp.Persistent.SQL
{
    public class MemberInfoRepository : IMemberInfoRepository
    {
        private string connectionString;

        public MemberInfoRepository(string connectionString)
        {
            this.connectionString = connectionString;
        }

        public Tuple<Exception, MemberInfo> GetMemberInfo()
        {
            try
            {
                using (var conn = new SqlConnection(this.connectionString))
                {
                    var result = conn.QueryFirstOrDefault<MemberInfo>(
                        "SPName",
                        param,
                        commandType: CommandType.StoredProcedure);

                    return Tuple.Create<Exception, MemberInfo>(null, result);
                }
            }
            catch (Exception ex)
            {
                return Tuple.Create<Exception, MemberInfo>(ex, null);
            }
        }
    }
}
  • Mongo版本
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namespace WebApp.Persistent.Mongo
{
    public class MemberInfoRepository : IMemberInfoRepository
    {
        private const string collectionName = "MemberInfo";
        private MongoClient client { get; set; }
        private IMongoDatabase db { get; set; }
        private IMongoCollection<MemberInfo> collection { get; set; }

        static MemberInfoRepository()
        {
            BsonClassMap.RegisterClassMap<MemberInfo>(cm =>
            {
                cm.AutoMap();
                cm.SetIgnoreExtraElements(true);
            });
        }

        public MemberInfoRepository(string connectionString, string dbName)
        {
            client = new MongoClient(connectionString);
            db = client.GetDatabase(dbName);
            collection = db.GetCollection<MemberInfo>(collectionName);
        }

        public Tuple<Exception, MemberInfo> GetMemberInfo()
        {
            try
            {
                var result = this.collection.Aggregate().FirstOrDefault();
                return Tuple.Create<Exception, MemberInfo>(null, result);
            }
            catch (Exception ex)
            {
                return Tuple.Create<Exception, MemberInfo>(ex, null);
            }
        }
    }
}

請搭配Autofac服用

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