删除条款中的NOT NOT-Linq-To-SQL

Question

Currently, I am writing a MiddleWare application that synchronizes information between and accounting application (ie Quickbooks) and a SQL database. I am fairly new to Linq-To-SQL and am currently struggling with what originally appeared to be a simple problem.

In short, I have logic that queries the chart of accounts from the accounting application (ie AR, Income, Expense, Liability, etc...). Then, my Middleware has to determine whether or not it needs to insert, update, or delete an account in the Accounts table of the SQL database for each record. Figuring out whether or not the operation is insert or delete was pretty easy to figure out but, I am struggling with the case where an account is deleted from Quickbooks and needs to be deleted from my SQL database. I'd like to run a Linq-To-Sql query that basically deletes all records from the Account table where the ListID is not in the list of ListIDs retrieved from a query. Is there some easy way to perform this in Linq-To-Sql?

Answer 1

Assuming you've populated a list of ListIDs (listOfIDs) in a separate query:

var accounts = from a in db.Accounts
               where !listOfIDs.Contains(a.ListID)
               select a;
db.Accounts.RemoveAll(accounts);
db.SubmitChanges();

Answer 2

db.accounts.Where(x => !ListIDs.Contains(x.ID))

Answer 3

request it with lambda or simple linq like said before. then

db.accounts.Attach(yourObject);
db.accounts.DeleteOnSubmit(yourObject);
db.SubmitChanges();

of course.. protect it with try/catch and welcome to Linq !!!

Answer 4

You didn't say which SQL driver you're using, but whichever one it is (a pretty short list), it's certain that the driver uses the QuickBooks SDK to access to the chart of accounts. The SDK has a special query for the purpose of finding deleted entities (such as accounts) called ListDeletedQuery . As a general rule, it is more efficient to use ListDeletedQuery if you want to find out what's been deleted. However, since the chart of accounts is usually quite small, it's probably acceptable scan the entire list in order to find missing elements as you are doing. Also, ListDeletedQuery may not be exposed by the SQL driver that you're using.