DataTypes

BTrees

• IIBTree -- maps integers to integers:
  • Usage: from BTrees.IIBTree import IIBTree
• IOBTree -- maps integers to objects:
  • Usage: from BTrees.IOBTree import IOBTree
• OIBTtree -- maps objects to integers:
  • Usage: from BTrees.OIBTree import OIBTree
• OOBTree -- maps objects to objects:
  • Usage: from BTrees.OOBTree import OOBTree

Buckets

• Buckets behave like BTree objects and therefore like dictionaries except Buckets do not implement the insert() method. Buckets are the smallest unit used by ZODB to store data. All datastructures consist of one or more buckets.
  • Usage: from BTrees.IIBTree import IIBucket
  • Usage: from BTrees.OOBTree import OOBucket

Sets

• IISet -- set of integers:
  • Usage: from BTrees.IIBTree import IISet
• OOSet -- set of objects:
  • Usage: from BTrees.OOBTree import OOSet

Sets store their data in a single bucket

TreeSets

• TreeSets behave like normal sets except they do not implement __getitem__()
  • Usage: from BTrees.IIBTree import IITreeSet
  • Usage: from BTrees.OOBTree import OOTreeSet

TreeSets store their data in one or more buckets Assuming you will store your set in a ZODB, the advantage that a TreeSet has over a Set is that, after a modification, only changed buckets need to be updated in the database. This improves efficiency and reduces conflict processing.