Just dipping my toes into Linq2sql project after years of rolling my own SQL Server DB access routines.
Before I spend too much time figuring out how to make linq2sql behave like my custom code used to, I want to check to make sure that it isn’t already ‘built’ in behavior that I can just use by setting up the relationships right in the designer…
Very simple example:
I have two tables: Person and Notes, with a 1 to many relationship (1 Person, many notes), linked by Person.ID->Note.PersonID.
I have a stored procedure (all data access is done via SP’s and I plan on continuing that) which makes the Link2SQL a bit more work for me.
sp_PersonGet(@ID int) which returns the person record and sp_PersonNotesGet(@PersonID) which returns a set of related notes for this person.
So far so good, I have an object:
Dim myPerson As Person = db.PersonGet(pnID).Single
and I can access my fields: myPerson.Name, myPerson.Phone etc.
and I can also do a
Dim myNotes As Notes = db.PersonNotesGet(pnID)
to get a set of notes and I can iterate thru this list like:
For Each N As Note In myNotes ( do something) Next
This all works fine…BUT….What I would prefer is that if I call:
myPerson = db.PersonGet(pnID)
that I also end up with a myPerson.Notes collection that I can iterate thru.
For Each N As Note In myPerson.Notes ( do something) Next
Basically, Linq2SQl would need to call 2 stored procedures each time a Person record is created…
Is this doable ‘out of the box’, or is this something I need to code around for myself?
This is normally what we would call child collections and they can be eager loaded or lazy loaded. Read these:
http://davidhayden.com/blog/dave/archive/2009/01/08/QuickExamplesLINQToSQLPerformanceTuningPerformanceProfilingORMapper.aspx
http://www.thinqlinq.com/default/Fetching-child-records-using-Stored-Procedures-with-LINQ-to-SQL.aspx