pymonetdb 0.1

Native MonetDB client Python API

Introduction

pymonetdb is a native python client API for monetDB. This API is cross-platform, and doesn’t depend on any monetdb libraries. It has support for python 2.5+, including Python 3 and PyPy and is Python DBAPI 2.0 compatible.

This is a fork of the original python-monetdb API. python-monetdb is bundled with the MonetDB software suite, but the release cycle is too long to fix small issues. Also I prefer working in github which also enables the use of travis-ci.

Installation

To install the MonetDB python API run the following command from the python source directory:

# python setup.py install

That’s all, now you are ready to start using the API.

Documentation

The python code is well documented, so if you need to find documentation you should have a look at the source code. Below is an interactive example on how to use the monetdb SQL API which should get you started quite fast.

Running the test suite

Install tox and run tox in the root.

You can control the testing behavior using environment variables:

* MAPIPORT - what port is MonetDB running? _50000_ by default
* TSTHOSTNAME -  where is MonetDB running? _localhost_ by default
* TSTPASSPHRASE - what passphrase to test control command? _testdb_ by default
* TSTDB -  what database to use for testing? _demo_ by default
* TSTUSERNAME - username, _monetdb_ by default
* TSTPASSWORD - password, _monetdb_ by default

Note that you first need to create and start a monetdb database. If you want to run the control tests you need to set a passphrase and enable remote control:

$ monetdb create demo
$ monetdb release demo
$ monetdbd set control=yes <path to dbfarm>
$ monetdbd set passphrase=testdb <path to dbfarm>

Examples

examples usage below:

> # import the SQL module
> import pymonetdb
>
> # set up a connection. arguments below are the defaults
> connection = pymonetdb.connect(username="monetdb", password="monetdb",
>                                    hostname="localhost", database="demo")
>
> # create a cursor
> cursor = connection.cursor()
>
> # increase the rows fetched to increase performance (optional)
> cursor.arraysize = 100
>
> # execute a query (return the number of rows to fetch)
> cursor.execute('SELECT * FROM tables')
26
>
> # fetch only one row
> cursor.fetchone()
[1062, 'schemas', 1061, None, 0, True, 0, 0]
>
> # fetch the remaining rows
> cursor.fetchall()
[[1067, 'types', 1061, None, 0, True, 0, 0],
 [1076, 'functions', 1061, None, 0, True, 0, 0],
 [1085, 'args', 1061, None, 0, True, 0, 0],
 [1093, 'sequences', 1061, None, 0, True, 0, 0],
 [1103, 'dependencies', 1061, None, 0, True, 0, 0],
 [1107, 'connections', 1061, None, 0, True, 0, 0],
 [1116, '_tables', 1061, None, 0, True, 0, 0],
 ...
 [4141, 'user_role', 1061, None, 0, True, 0, 0],
 [4144, 'auths', 1061, None, 0, True, 0, 0],
 [4148, 'privileges', 1061, None, 0, True, 0, 0]]
>
> # Show the table meta data
> cursor.description
[('id', 'int', 4, 4, None, None, None),
 ('name', 'varchar', 12, 12, None, None, None),
 ('schema_id', 'int', 4, 4, None, None, None),
 ('query', 'varchar', 168, 168, None, None, None),
 ('type', 'smallint', 1, 1, None, None, None),
 ('system', 'boolean', 5, 5, None, None, None),
 ('commit_action', 'smallint', 1, 1, None, None, None),
 ('temporary', 'tinyint', 1, 1, None, None, None)]

If you would like to communicate with the database at a lower level you can use the MAPI library:

> from pymonetdb import mapi
> server = mapi.Server()
> server.connect(hostname="localhost", port=50000, username="monetdb",
                 password="monetdb", database="demo", language="sql")
> server.cmd("sSELECT * FROM tables;")
...