Question

In order to process our daily transactions on the back office server, I need to pull the transactions from the web server’s database. What is the recommended approach to pull all records for a given date in a DateTime field on the SQL Server?

var transactions = from i in db.Transactions
                   where i.TransactionTimestamp.Year == transactionDate.Year && 
                         i.TransactionTimestamp.Month == transactionDate.Month && 
                         i.TransactionTimestamp.Day == transactionDate.Day
                   select new Transaction();

I got the following error when i tried the above:

System.NotSupportedException was unhandled

Message=The entity or complex type ‘db_eGovModel.Transaction’ cannot be constructed in a LINQ to Entities query.

Answer 1

You currently are querying for transactions, then throwing the result away and create a new Transaction instance from scratch – this is not what you want, also it will cause a runtime error since there is no equivalent of a transaction instance on the SQL side.

Instead just return the entities you queried for – Try this:

var transactions = from i in db.Transactions
                   where i.TransactionTimestamp.Year == transactionDate.Year && 
                         i.TransactionTimestamp.Month == transactionDate.Month && 
                         i.TransactionTimestamp.Day == transactionDate.Day
                   select i;