A Linq query will always start with From item in datasource
When I initially started using Linq, I thought that was a little odd, and why didn’t Microsoft just use SQL style Select columns from datasource. I thought about this for a minute, and realised that the problem with that is that you can’t use Intellisense to get the column names because you don’t actually know what they are until you’ve specified the data source.
Another reason for this is that the Select part of a Linq query is not compulsory, so it makes more sense to start with the part that is.
You might find it a little confusing having to specify item if you are thinking in SQL terms, as you would usually just include a table name and possibly an alias in SQL. The point in item is that a Linq query is a bit like a For loop in a single statement. You are effectively looping around the items in the data source. An individual provider might not actually implement it that way (Linq to SQL doesn’t – if you use a Where clause, it is translated to SQL instead of retrieving all the data and checking what matches), but that is the abstraction that we are using. We don’t reference the item by using the datasource name because we might still want to access something else in the datasource separately in the query.
- Linq Part 1 - What is Linq?
- Linq Part 2 - From
- Linq Part 3 - Query Format
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Tags: .NET, .NET 3.5, Language Integrated Query, Linq, VB.NET