優化查詢的聯盟，除了與LINQ和加入C＃

Question

我有2個對象（從XML加載列表）report和database（代碼波紋管顯示），我應該對其進行分析，並與標記項目0，1，2， 3根據一些條件

TransactionResultCode = 0; // SUCCESS (all fields are equivalents: [Id, AccountNumber, Date, Amount]) 
TransactionResultCode = 1; // Exists in report but Not in database 
TransactionResultCode = 2; // Exists in database but Not in report 
TransactionResultCode = 3; // Field [Id] are equals but other fields [AccountNumber, Date, Amount] are different. 

我會很高興，如果有人能找到時間來建議如何優化某些查詢。 貝婁是代碼：

謝謝！

 //TransactionResultCode = 0 - SUCCESS 
     //JOIN on all fields 
     var result0 = from d in database 
         from r in report 
         where (d.TransactionId == r.MovementID) && 
          (d.TransactionAccountNumber == long.Parse(r.AccountNumber)) && 
          (d.TransactionDate == r.MovementDate) && 
          (d.TransactionAmount == r.Amount) 
         orderby d.TransactionId 
         select new TransactionList() 
         { 
          TransactionId = d.TransactionId, 
          TransactionAccountNumber = d.TransactionAccountNumber, 
          TransactionDate = d.TransactionDate, 
          TransactionAmount = d.TransactionAmount, 
          TransactionResultCode = 0 
         }; 

     //******************************************* 
     //JOIN on [Id] field 
     var joinedList = from d in database 
         from r in report 
         where d.TransactionId == r.MovementID 
         select new TransactionList() 
         { 
          TransactionId = d.TransactionId, 
          TransactionAccountNumber = d.TransactionAccountNumber, 
          TransactionDate = d.TransactionDate, 
          TransactionAmount = d.TransactionAmount 
         }; 

     //Difference report - database 
     var onlyReportID = report.Select(r => r.MovementID).Except(joinedList.Select(d => d.TransactionId)); 

     //TransactionResultCode = 1 - Not Found in database 
     var result1 = from o in onlyReportID 
         from r in report 
         where (o == r.MovementID) 
         orderby r.MovementID 
         select new TransactionList() 
         { 
          TransactionId = r.MovementID, 
          TransactionAccountNumber = long.Parse(r.AccountNumber), 
          TransactionDate = r.MovementDate, 
          TransactionAmount = r.Amount, 
          TransactionResultCode = 1 
         }; 

     //******************************************* 

     //Difference database - report 
     var onlyDatabaseID = database.Select(d => d.TransactionId).Except(joinedList.Select(d => d.TransactionId)); 

     //TransactionResultCode = 2 - Not Found in report 
     var result2 = from o in onlyDatabaseID 
         from d in database 
         where (o == d.TransactionId) 
         orderby d.TransactionId 
         select new TransactionList() 
         { 
          TransactionId = d.TransactionId, 
          TransactionAccountNumber = d.TransactionAccountNumber, 
          TransactionDate = d.TransactionDate, 
          TransactionAmount = d.TransactionAmount, 
          TransactionResultCode = 2 
         }; 

     //******************************************* 

     var qwe = joinedList.Select(j => j.TransactionId).Except(result0.Select(r => r.TransactionId)); 

     //TransactionResultCode = 3 - Transaction Results are different (Amount, AccountNumber, Date,) 
     var result3 = from j in joinedList 
         from q in qwe 
         where j.TransactionId == q 
         select new TransactionList() 
         { 
          TransactionId = j.TransactionId, 
          TransactionAccountNumber = j.TransactionAccountNumber, 
          TransactionDate = j.TransactionDate, 
          TransactionAmount = j.TransactionAmount, 
          TransactionResultCode = 3 
         }; 

Answer 1

，你可以嘗試類似如下：

public void Test() 
{ 
    var report = new[] {new Item(1, "foo", "boo"), new Item(2, "foo2", "boo2"), new Item(3, "foo3", "boo3")}; 
    var dataBase = new[] {new Item(1, "foo", "boo"), new Item(2, "foo22", "boo2"), new Item(4, "txt", "rt")}; 

    Func<Item, bool> inBothLists = (i) => report.Contains(i) && dataBase.Contains(i); 
    Func<IEnumerable<Item>, Item, bool> containsWithID = (e, i) => e.Select(_ => _.ID).Contains(i.ID); 

    Func<Item, int> getCode = i => 
            { 
             if (inBothLists(i)) 
             { 
              return 0; 
             } 
             if(containsWithID(report, i) && containsWithID(dataBase, i)) 
             { 
              return 3; 
             } 
             if (report.Contains(i)) 
             { 
              return 2; 
             } 
             else return 1; 
            }; 

    var result = (from item in dataBase.Union(report) select new {Code = getCode(item), Item = item}).Distinct(); 
} 

public class Item 
{ 
    // You need also to override Equals() and GetHashCode().. I omitted them to save space 
    public Item(int id, string text1, string text2) 
    { 
     ID = id; 
     Text1 = text1; 
     Text2 = text2; 
    } 

    public int ID { get; set; } 
    public string Text1 { get; set; } 
    public string Text2 { get; set; } 
} 

請注意，您需要可以實現Equals()你的物品，或實施IEqualityComparer<>和飼料它Contains()方法。