RecSQL is a hack that allows one to load table-like data records into an in-memory sqlite database for quick and dirty analysis via SQL. The SQLarray class has additional SQL functions such as sqrt or histogram defined. SQL tables can always be returned as numpy record arrays so that data can be easily handled in other packages such as numpy or …
Python

README.rst

README

Documentation Status

RecSQL's basic idea is to treat numpy record arrays like SQL tables. What it does, in fact, is to represent the arrays as real SQL tables (using SQLite) and provide convenience functions to return recarrays on demand.

This works ok for small tables but less so if you want to access gigabytes of data as recarrays. It's a hack.

Documentation can be found at http://recsql.readthedocs.org/

Source code is available from https://github.com/orbeckst/RecSQL under the GNU General Public License, version 3 (see also the file LICENSE in the distribution).

Example

>>> from recsql import SQLarray
>>> import numpy
>>> a = numpy.rec.fromrecords(numpy.arange(100).reshape(25,4), names='a,b,c,d')
>>> Q = SQLarray('my_name', a)
>>> print repr(Q.recarray)
rec.array([(0, 1, 2, 3), (4, 5, 6, 7), (8, 9, 10, 11), (12, 13, 14, 15),
       (16, 17, 18, 19), (20, 21, 22, 23), (24, 25, 26, 27),
       (28, 29, 30, 31), (32, 33, 34, 35), (36, 37, 38, 39),
       (40, 41, 42, 43), (44, 45, 46, 47), (48, 49, 50, 51),
       (52, 53, 54, 55), (56, 57, 58, 59), (60, 61, 62, 63),
       (64, 65, 66, 67), (68, 69, 70, 71), (72, 73, 74, 75),
       (76, 77, 78, 79), (80, 81, 82, 83), (84, 85, 86, 87),
       (88, 89, 90, 91), (92, 93, 94, 95), (96, 97, 98, 99)],
      dtype=[('a', '<i4'), ('b', '<i4'), ('c', '<i4'), ('d', '<i4')])
>>> Q.SELECT('*', 'WHERE a < 10 AND b > 5')
rec.array([(8, 9, 10, 11)],
    dtype=[('a', '<i4'), ('b', '<i4'), ('c', '<i4'), ('d', '<i4')])
# creating new SQLarrays:
>>> R = Q.selection('a < 20 AND b > 5')
>>> print R
<recsql.sqlarray.SQLarray object at 0x...>

Availability

The latest version of the package is available on GitHub https://github.com/orbeckst/RecSQL

RecSQL is also listed on PyPi http://pypi.python.org/pypi/RecSQL and can thus be installed with

pip install RecSQL

See :doc:`INSTALL` for further installation instructions.

A git repository of the package is hosted at http://github.com/orbeckst/RecSQL .

Getting Involved

Please submit problems, questions and questions through the issue tracker. Pull requests are also very welcome.