Why does the Visual Studio conversion wizard 2010 create a massive SDF database file?

I've opened a 2009 C++ sln in 2010 and run the Visual Studio开发者_运维问答 2010 conversion wizard. It seems to have done the conversion fine, but there's a 60 MB .sdf file created with the same name as my .sln file (apart from extension)! There was no sdf file before. I'm pretty sure when I've used the wizard on C# projects this file hasn't been created.

It looks like it's created to help the conversion wizard, but I don't see why it's left when the wizard has finished. The tables in the database are:

assoc_spans
assoc_text
base_class_parents
code_item_kinds
code_items
config_files
configs
file_map
file_signatures
files
parsers
projects
properties
refs
symbols

I assume I can just delete this file?

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It is the code browser database, it replaces the NCB file in earlier releases. In VC++ 2010 the intellisense and browsing features have been completely redesigned to provide greater functionality and accuracy.

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It's the browsing database. You may delete it; it will be recreated.