Re: Verifying a database.

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Colin Barnette wrote:
> Hello, I'm writing a sqlite database accessprogram and I am wondering
> how I might be able to verify that a specified file by the user really
> is a sqlite database.
> 
> I tried:
> 
>        try:
>            dbcon = sqlite.connect(self.dbpath[0])
>            db = dbcon.cursor()
>        except:
>            print "Database Open Error."
> 
> but, it seems that even if the file is a .jpg or .py it still makes
> the connection.

SQLite doesn't actually look at the contents of the file until you issue
a query.  At that point it reads the schema etc if it hasn't done so
already.  The connect will also work for non-existent files.  You could
try this code (my mail client will wrap it).

try:
  sqlite.connection(self.dbpath[0]).cursor().execute("select count(*)
from sqlite_master")
except:
  print "Database error"

Note that this can also fail for other reasons.  For example if there is
a virtual table in the database and it hasn't been registered yet.

Another test is this.

open(self.dbpath[0], "rb").read(16)=="SQLite format 3\0"

You must make sure that the filename is unicode though.  If it is not in
ascii or unicode then Python may convert it one way and SQLite will
convert it another way and you'll end up referring to different files.

Roger
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