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I have a malformed database. When I try to get records from any of two tables, it throws an exception:

DatabaseError: database disk image is malformed

I know that through commandline I can do this:

sqlite3 ".dump" base.db | sqlite3 new.db

Can I do something like this from within Python?

Sergey Vyacheslavovich Brunov
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GriMel
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  • http://stackoverflow.com/questions/5274202/sqlite3-database-or-disk-is-full-the-database-disk-image-is-malformed ... take a look at `pegolon` answer – Busturdust Jan 19 '16 at 17:13
  • I need to do this through sqlite3 methods only if it's possible. – GriMel Feb 01 '16 at 19:54

2 Answers2

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As far as i know you cannot do that (alas, i might be mistaken), because the sqlite3 module for python is very limited.

Only workaround i can think of involves calling the os command shell (e.g. terminal, cmd, ...) (more info) via pythons call-command:

Combine it with the info from here to do something like this:

This is done on an windows xp machine: Unfortunately i can't test it on a unix machine right now - hope it will help you:

    from subprocess import check_call

    def sqliterepair():
        check_call(["sqlite3", "C:/sqlite-tools/base.db", ".mode insert", ".output C:/sqlite-tools/dump_all.sql", ".dump", ".exit"])
        check_call(["sqlite3", "C:/sqlite-tools/new.db", ".read C:/sqlite-tools/dump_all.sql", ".exit"])
        return

The first argument is calling the sqlite3.exe. Because it is in my system path variable, i don't need to specify the path or the suffix ".exe". The other arguments are chained into the sqlite3-shell.

Note that the argument ".exit" is required so the sqlite-shell will exit. Otherwise the check_call() will never complete because the outer cmd-shell or terminal will be in suspended.

Of course the dump-file should be removed afterwards...

EDIT: Much shorter solution (credit goes to OP (see comment))

os.system("sqlite3 C:/sqlite-tools/base.db .dump | sqlite3 C:/sqlite-tools/target.db")

Just tested this: it works. Apparently i was wrong in the comments.

Toastgeraet
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    I'll approve your answer. But I have a question. Can't we just call ```os.system("sqlite3 '.dump' base.db | sqlite3 new.db")```? – GriMel Feb 09 '16 at 21:25
  • My answer was structured for a windows xp cmd shell. I believe your comment would work fine on unix-like systems (linux etc...). Unfortunetly, as far as i know, the piping capabilities of Microsofts standard cmdshell seem rather limited. – Toastgeraet Feb 22 '16 at 13:41
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If I understood properly, what you want is to duplicate an sqlite3 database in python. Here is how I would do it: 

# oldDB = path to the corrupted db, 
# newDB = path to the new db
def duplicateDB(oldDB, newDB):

    con = sqlite3.connect(oldDB)
    script = ''.join(con.iterdump())
    con.close()

    con = sqlite3.connect(newDB)
    con.executescript(script)
    con.close()

    print "duplicated %s into %s" % (oldDB,newDB)

In your example, call duplicateDB('base.db', 'new.db'). The iterdump function is equivalent to dump.

Note that if you use Python 3, you will need to change the print statement.

Derlin
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    I know about ```iterdump```, but the main problem is that the database is malformed, so executing ```con.iterdump()``` will throw an exception ```DatabaseError```. – GriMel Feb 03 '16 at 08:59