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How to update database using LINQ in F#
f#compilerlinq

How to update database using LINQ in F#?

open Microsoft.FSharp.Linq.Query
open Microsoft.FSharp.Linq.QuotationEvaluation

let q =
<@ seq { for i in db.projects do
if i.projectId = 2 then
i.projectName <- "aaa"} @>
query q

This code doesn't work!!!!! It gives me the following error message:

"Microsoft.FSharp.Core.FailureException: The following construct was used in query but is not recognised by the F#-to-LINQ query translator:
...
This is not a valid query expression. Check the specification of permitted queries and consider moving some of the query out of the quotation"

The compiler told me to check permitted queries, but I've gone through the F# specification, can't find any information. Did I missed anything?

Please help!!

.

Uhm... please don't omit the single most valuable piece of information in your postings ;) . The message should tell you that the problem lies in the property setter - LINQ queries simply can't update data.
Query the desired entities, manipulate them on the client and let the change tracking magic of your LINQ provider do the rest.

Something like

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let dc = YourDataContext()
let customer = query <@ seq { for c in dc.Customers do if c.Id = 3 then yield c } @>

customer.Foo <- 3
dc.SubmitChanges()
By on 10/13/2009 10:19 AM ()

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