Cannot insert duplicate key row in object

Problem: Error occurred in deployment step 'Add Solution': Cannot insert duplicate key row in object 'dbo.Solutions' with unique index 'Solutions_BySiteAndSolutionId'.

Initial Hypothesis: Sandbox solution wsp deployment is causing the error. I delete and created a new site collection with an identical url.

Solution:
for the see the solution see next blog ->
http://blog.sharepointsite.co.uk/2010/12/cannot-insert-duplicate-key-row-in.html