What is PyTables?
PyTables is a package for managing hierarchical datasets and designed to efficiently and easily cope with extremely large amounts of data. You can download PyTables and use it for free. You can access documentation, some online examples and presentations in the HowToUse section.
PyTables is built on top of the HDF5 library, using the Python language and the numarray package (it also supports NumPy and Numeric right out of the box). It features an object-oriented interface that, combined with C extensions for the peformance-critical parts of the code (generated using Pyrex), makes it a fast, yet extremely easy to use tool for interactively saving and retrieving very large amounts of data. One important feature of PyTables is that it optimizes memory and disk resources so that data takes much less space (a factor between 3 and 5, and more if the data is compressible) than other solutions such as relational or object oriented databases.
You can have a look at the MainFeatures of PyTables. Also, find more info by reading the PyTables FAQ.