Question

Next SubSonic3 query gives me an error:

Db.Update<Tag>()
    .SetExpression("Popularity")
    .EqualTo("Popularity+1")
    .Where<Tag>(x => x.TagId == tagId)
    .Execute();

Error: failed: System.FormatException : Failed to convert parameter value from a String to a Int32.

The sql that is generated is ok, but the collection of parameters contains two parameters that need to be set.

UPDATE [Tagging].[Tag] 
SET Popularity=Popularity+1
WHERE [Tagging].[Tag].[TagId] = @0

One of the parameters set @up_Popularity to ‘Popularity+1’. Since this is the first parameter being set, sql triese to assign this string ‘Popularity+1’ to an integer.

Is this a bug or am I doing something wrong?

Answer 1

Db.Update<Tag>()
    .SetExpression("Popularity = Popularity + 1")
    .Where<Tag>(x => x.TagId == tagId)
    .Execute();

This should work … but I think it’s for wholesale updates. Not sure. Your best bet is to use our CodingHorror:

new CodingHorror("UPDATE Tags SET Popularity = Popularity + 1 WHERE @1", 
  tagId).Execute();