CODEWITHSUNDEEP
c#linq
Arseniy
Arseniy

Reputation: 879

How can I shorten linq query?

I have to show one row per one bill in my program, but one bill has more than 1 sub-bills. I would like to group information from 2 tables in one DataGridView. 1 row must show grouped info about all sub-bills. Only 2 columns are more complex than other: "Description" and "Sum". "Description" must contain all of descriptions of sub-bills and be delimited by new-line. I made it next way:

var documentQuery = (from doc in entities.Bas_DocumentData
                select new 
                        {
                            DocumentNum = doc.DocumentNum,
                            DocumentDate = doc.DocumentDate,
                            Description = doc.Bas_BonusData.Select(t => t.Description),
                            BillsCount = doc.Bas_BonusData.Count,
                            SupplierNum = doc.Bas_BonusData.Select(cred => cred.SupplierNum).FirstOrDefault(),
                            Debitor = doc.Bas_BonusData.Select(deb => deb.DebitorNum).FirstOrDefault(),
                            Manager = doc.Bas_BonusData.Select(manager => manager.ManagerName).FirstOrDefault(),
                            SupplierName = doc.Bas_BonusData.Select(supp => supp.SupplierName).FirstOrDefault(),
                            Sum = doc.Bas_BonusData.Sum(bill => bill.Price),
                            IsPrinted = doc.isPrinted,
                            IsSent = doc.isSent,
                            NotSummarize = doc.NotSummarize
                        }).OrderBy(key => key.DocumentNum)
                        .ToList()
                        .Select(q => new AcceptedBonusProjection
                        {
                            DocumentNum = q.DocumentNum,
                            DocumentDate = q.DocumentDate,
                            Description = String.Join("\n\r", q.Description.ToArray()),
                            BillsCount = q.BillsCount,
                            SupplierNum = q.SupplierNum,
                            Debitor = q.Debitor,
                            Manager = q.Manager,
                            SupplierName = q.SupplierName,
                            Sum = q.Sum,
                            IsPrinted = q.IsPrinted,
                            IsSent = q.IsSent,
                            NotSummarize = q.NotSummarize
                        });

Is there better way to achieve my goal? Which way can I shorten this query?

Upvotes: 2

Views: 364

Answers (1)

Random Dev
Random Dev

Reputation: 52280

The first half (anony. struct) is not needed at all:

var documentQuery = 
   entities.Bas_DocumentData
   .OrderBy(key => key.DocumentNum)
   .Select(q => new AcceptedBonusProjection
                        {
                            DocumentNum = q.DocumentNum,
                            /* same as in your select snipped here as it does not add value */
                            NotSummarize = q.NotSummarize
                        })
   .ToList();

Remark: Please note that you do some subqueries that might not scale well (selecting from another table in your queries, for example doc.Bas_BonusData.Select(manager => manager.ManagerName).FirstOrDefault()) - this will NOT be translated into a inner/outer-join and will result in many DB-queries. Eager loading will not solve this problem! You should consider using a SQL-View/StoredProcedure/LINQ-Join Statements to change this.

Upvotes: 4

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