Updating data using linq to sql

19-May-2016 20:32 by 4 Comments

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Then, LINQ to SQL iterates all rows return, flags them as deleted, then generates a single DELETE statement.

So extending on my ‘first10’ Query Syntax example variable above my update might have looked like this: Now the immediate downside you’ll notice to this, which is basically completely contradictory to O/R Mapping frameworks, is that I will get no intellisense or type checking on the Author property.In addition to this overhead, Jeffery did not like the need to call Submit Changes() on the Data Context object to confirm database changes.Now I whole heartedly agree about combining simple DELETE SQL statements into one, but I actually disagree with the desire to eliminate the call to Submit Changes(). In a LINQ to SQL utopian world, executing the C# code above, the provider would generate So how can we do this?However, I accepted this because: On a bit of a side note, although it does have a purpose, at this point, I was all proud of myself.I had created the extension methods and was ready to write my first technical blog (until this point my website was all personal).In Jeffrey’s article, he gave an example of ‘deleting all rows where creation date was older than a month’.

This is a perfect example of when a O/R Mapping framework issues multiple delete statements when a single ‘simple’ SQL statement could be written.

Since I recently converted my site to blogengine.net, I’ll use its database schema for all examples to follow.

In addition to this, all code snippets you’ll see were run in LINQPad, which at the moment is by far my favorite development tool that I’m using (now if they’d only get intellisense in there, I’d play with this program all day long).

So, now Utopia would end up with a SQL statement like so: DELETE [be_Posts] FROM [be_Posts] AS j0 INNER JOIN ( SELECT [t0].[Post ID] FROM [be_Posts] AS [t0] WHERE ([t0].[Date Created]) < @p0 ) AS j1 ON (j0.[Post ID] = j1.[Post ID]) -- @p0: Input Date Time -- (Size = 0; Prec = 0; Scale = 0) [3/13/2008 AM] entities ) function. Add Months( -1 ) ) < 0 select p; var my Posts = from p in old Posts where p.

In addition to having a similar interface, it also allows you to build up your final IQueryable parameter through multiple Query Syntax queries. I know this could be written in a single Lambda expression, but I would find it easier to read and maintain as individual queries. Author == "Terry Aney" select p; var first10 = my Posts. Admittedly, the Delete Batch() extension method was pretty easy to implement.

A couple weeks ago, I read the article, LINQ to SQL Extension: Batch Deletion with Lambda Expression by Jeffrey Zhao.