How to create .mdb file?

Question

I am new with zarr, HDF5 and LMDB. I have converted data from HDF5 to Zarr but i got many files with extension .n (n from 0 to 31). I want to have just one file with .zarr extension. I tried to use LMDB (zarr.LMDBStore function) but i don't understand how to create .mdb file ? Do you have an idea how to do that ? Thank you !

Answer 1

You'll probably want to have an Access DAO/ADO/VBA reference handy for the methods that are used, however, as the comtypes module generates COM library wrappers dynamically, so there's no built-in documentation.

Here's a brief example of how it works. (Go ahead and test it out yourself.)

from comtypes.client import CreateObject

access = CreateObject('Access.Application')

from comtypes.gen import Access

DBEngine = access.DBEngine
db = DBEngine.CreateDatabase('test.mdb', Access.DB_LANG_GENERAL)
      # For me, test.mdb was created in my My Documents folder when I ran the script 

db.BeginTrans()

db.Execute("CREATE TABLE test (ID Text, numapples Integer)")
db.Execute("INSERT INTO test VALUES ('ABC', 3)")

db.CommitTrans()
db.Close(

)

(Moved the second import statement after the CreateObject line for cases where the Python wrapper module for the typelibrary didn't previously exist.)

Answer 2

@kish When trying your solution i got this error:

from comtypes.gen import Access ImportError: cannot import name 'Access'

Answer 3

There are some examples of using LMDB as a Zarr store in the documentation for the LMDBStore class . Eg:

>>> store = zarr.LMDBStore('data/group.mdb')
>>> root = zarr.group(store=store, overwrite=True)
>>> foo = root.create_group('foo')
>>> bar = foo.zeros('bar', shape=(10, 10), chunks=(5, 5))
>>> bar[...] = 42
>>> store.close()  # don't forget to call this when you're done

You don't have to do anything other than the above to create the .mdb file, it will be created automatically.