Question

For the sake of context, I am working on a 1 time data conversion from several Excel sheets that I have imported into a Database. The data is not normalized and I am trying to normalize it.

I have 3 tables in a SQL Database. They are called OldAssets, OldTransactions, and OldUsers.

OldTransactions has 7903 records. OldUsers has 7437. OldAssets has 9764

I am using LINQ to SQL to query these tables using this code

from oa in OldAssets
from ot in OldTransactions
from u in OldUsers
where (oa.Asset_Serial_Number == ot.Asset_Serial_Number  && ot.User_EID == u.User_EID  && ot.Asset_Tag == oa.Asset_Tag)
select new Transactions { 
            DevCenter = ot.Transaction_Dev_Center,
            Action  =   ot.Transaction_Action, 
            Status  =   ot.Transaction_Status,
            ModificationDate =  ot.Modified,
            ModifiedBy = ot.ModifiedBy,
            CreatedBy = ot.CreatedBy,
            TransactionDate = (System.DateTime)ot.Transaction_Date,
            Transaction_Asset = (System.Int32)oa.ID,
            Transaction_User = (System.Int32)u.ID }

I am trying to go through all of my OldTransactions and for each OldTransaction, create a new transaction that specifies the Transaction_Asset and the Transaction_User based on the mapping of an asset serial number and a user_EID.

My result is giving me just over 10,000 records of new “Transactions.” I don’t understand how I could be getting more records than the number of OldTransactions I have.

What query can I write that will return a single new Transaction for every OldTransaction, but with the added properties of Transaction_Asset and Transaction_User based on the mapping of serial_number and User_EID?

Answer 1

From you question it looks like you just want to copy all transactions with additional data. I think something like this could work:

from ot in OldTransactions
select new Transactions {
        DevCenter = ot.Transaction_Dev_Center,
        Action  =   ot.Transaction_Action,
        Status  =   ot.Transaction_Status,
        ModificationDate =  ot.Modified,
        ModifiedBy = ot.ModifiedBy,
        CreatedBy = ot.CreatedBy,
        TransactionDate = (System.DateTime)ot.Transaction_Date,
        Transaction_Asset = (System.Int32)(
             from oa in OldAssets 
             where oa.Asset_Serial_Number == ot.Asset_Serial_Number && 
                   ot.Asset_Tag == oa.Asset_Tag
             select oa.ID).FirstOrDefault(),
        Transaction_User = (System.Int32)(
             from u in OldUsers 
             where ot.User_EID == u.User_EID
             select u.ID).
                 FirstOrDefault()) }