If I have a table in SQL 2008 R2 with a nullable column of type Decimal(35,18) and pull that into the edmx. The largest decimal value I can successfully save to the DB without getting a Conversion Overflows error is
79,228,162,514
This is very odd as this matches the upper bounds of Decimal (if you compare digits not in actual value)
http://msdn.microsoft.com/en-us/library/system.decimal.maxvalue.aspx
79,228,162,514,264,337,593,543,950,335
However I am not even close to the max 28 digits.
I filed a bug as I believe it is... but I can't believe it is as this would be a HUGE issue?