Some Simple LINQ To SQL Queries
Given a table MyTable, with the rows ID int, Value1 varchar(100), Value2 varchar(100) and a data context (created automatically by visual studio) you can create/update/delete data very easily. I will be using LINQ To SQL here, which is somewhat out of date now with the introduction of the Entity Framework, but I will post up some EF examples in a later post (they’re not much different in the code.) The language is C#.
Simple L2S Examples
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 | using (DBDataContext db = new DBDataContext()) { // get all var search = from t in dc.MyTable select t; // this will return all the records List<MyTable> all = search.ToList(); // get all (example 2) This one doesn't use a search variable. List<MyTable> all2 = dc.MyTable.ToList(); // get single var search2 = from t in dc.MyTable where t.ID == 1 select t; // if none is found, then record will be NULL. MyTable record = search2.SingleOrDefault(); // get single (example 2) This one uses a predicate which defines // 's' as a placeholder, and then sets the conditions for s to be s.ID == 1. MyTable record2 = dc.MyTable.SingleOrDefault(s => s.ID == 1); // update a value in the record record2.Value1 = "Hello!"; db.SubmitChanges(); // delete the record db.MyTable.DeleteOnSubmit(record2); db.SubmitChanges(); } |
Follow Dave on Twitter