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For 2023 (and 2024 ...) - we are now fully retired from IT training.
We have made many, many friends over 25 years of teaching about Python, Tcl, Perl, PHP, Lua, Java, C and C++ - and MySQL, Linux and Solaris/SunOS too. Our training notes are now very much out of date, but due to upward compatability most of our examples remain operational and even relevant ad you are welcome to make us if them "as seen" and at your own risk.

Lisa and I (Graham) now live in what was our training centre in Melksham - happy to meet with former delegates here - but do check ahead before coming round. We are far from inactive - rather, enjoying the times that we are retired but still healthy enough in mind and body to be active!

I am also active in many other area and still look after a lot of web sites - you can find an index ((here))
Joining a MySQL table from within a Python program

Python is a big subject.

MySQL is a big subject.

Yet the two fin so well together that they can be firmly linked, and work well together, using the tiniest drops of glue.

I've provided examples here before, but in answer to a request from a recent delegate, I've just added a fresh example onto our web site. The request was for an example that shows how to join two tables are report the results through a Python program.

1. Load in an appropriate module, and connect to the database:

import MySQLdb
db = MySQLdb.connection(host="127.0.0.1",
  user="graham", passwd="abc123", db="whm")


2. Run the query, and store the result

db.query("""select guests.rid, name, about, locate
  from guests join rooms on guests.rid = rooms.rid""")
r = db.store_result()


3. Step through the result set, row by row

for row in r.fetch_row(0):
  print row


Full source code of my example is [here], and that includes a data dump (mysqldump) of both of the tables - a table of rooms and a table of guests.

By joining the room table and the guest table (the guest table including just a note of the room NUMBER that a guest stayed in), we can find out who had a shower and who had a bath ... and whether they looked out over the back, side or front:

[trainee@holt px]$ python pysql_another
('2', 'John Smith', 'Shower', 'side')
('4', 'Jane and John Brown', 'Shower', 'side')
('5', 'Boris Morrison', 'Bath and Shower', 'front')
[trainee@holt px]$


(written 2010-06-02)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
Y115 - Additional Python Facilities
  [183] The elegance of Python - (2005-01-19)
  [208] Examples - Gadfly, NI Number, and Tcl to C interface - (2005-02-10)
  [239] What and why for the epoch - (2005-03-08)
  [463] Splitting the difference - (2005-10-13)
  [663] Python to MySQL - (2006-03-31)
  [672] Keeping your regular expressions simple - (2006-04-05)
  [753] Python 3000 - the next generation - (2006-06-09)
  [901] Python - listing out the contents of all variables - (2006-10-21)
  [1043] Sending an email from Python - (2007-01-18)
  [1136] Buffering output - why it is done and issues raised in Tcl, Perl, Python and PHP - (2007-04-06)
  [1149] Turning objects into something you can store - Pickling (Python) - (2007-04-15)
  [1305] Regular expressions made easy - building from components - (2007-08-16)
  [1336] Ignore case in Regular Expression - (2007-09-08)
  [1337] A series of tyre damages - (2007-09-08)
  [1876] Python Regular Expressions - (2008-11-08)
  [2407] Testing code in Python - doctest, unittest and others - (2009-09-16)
  [2435] Serialization - storing and reloading objects - (2009-10-04)
  [2462] Python - how it saves on compile time - (2009-10-20)
  [2655] Python - what is going on around me? - (2010-02-28)
  [2721] Regular Expressions in Python - (2010-04-14)
  [2745] Connecting Python to sqlite and MySQL databases - (2010-04-28)
  [2746] Model - View - Controller demo, Sqlite - Python 3 - Qt4 - (2010-04-29)
  [2764] Python decorators - your own, staticmethod and classmethod - (2010-05-14)
  [2765] Running operating system commands from your Python program - (2010-05-14)
  [2786] Factory methods and SqLite in use in a Python teaching example - (2010-05-29)
  [3089] Python regular expressions - repeating, splitting, lookahead and lookbehind - (2010-12-17)
  [3442] A demonstration of how many Python facilities work together - (2011-09-16)
  [3469] Teaching dilemma - old tricks and techniques, or recent enhancements? - (2011-10-08)
  [4085] JSON from Python - first principles, easy example - (2013-05-13)
  [4211] Handling JSON in Python (and a csv, marshall and pickle comparison) - (2013-11-16)
  [4298] Python - an interesting application - (2014-09-18)
  [4439] Json is the new marshall, pickle and cPickle / Python - (2015-02-22)
  [4451] Running an operating system command from your Python program - the new way with the subprocess module - (2015-03-06)
  [4536] Json load from URL, recursive display, Python 3.4 - (2015-10-14)
  [4593] Command line parameter handling in Python via the argparse module - (2015-12-08)
  [4709] Some gems from Intermediate Python - (2016-10-30)

Y113 - Python and SQL databases
  [3136] A framework with python - Django - first steps - (2011-01-17)
  [3139] Steering our Python courses towards wxPython, SQLite and Django - (2011-01-19)
  [4024] SQL databases from Python - an SQLite example - (2013-03-02)
  [4086] Cacheing class for Python - using a local SQLite database as a key/value store - (2013-05-14)
  [4436] Accessing a MySQL database from Python with mysql.connector - (2015-02-21)
  [4445] Graphing presentations in Python - huge data, numpy and matplotlib - (2015-02-28)
  [4535] SQLAlchemy - first examples with a Python Object Relationship Mapping system - (2015-10-14)
  [4537] example of SQLite using a local database file through SQLalchemy - (2015-10-14)

S156 - Interfacing Applications to MySQL Databases
  [104] mysql_connect or mysql_pconnect in PHP? - (2004-10-30)
  [644] Using a MySQL database from Perl - (2006-03-13)
  [723] Viewing images held in a MySQL database via PHP - (2006-05-17)
  [1381] Using a MySQL database to control mod_rewrite via PHP - (2007-10-06)
  [1450] Easy selection of multiple SQL conditions from PHP - (2007-11-30)
  [1518] Downloading data for use in Excel (from PHP / MySQL) - (2008-01-25)
  [1561] Uploading to a MySQL database through PHP - examples and common questions - (2008-03-02)
  [1885] Hiding a MySQL database behind a web page - (2008-11-15)
  [2263] Mysqldump fails as a cron job - a work around - (2009-06-30)
  [2381] Checking the database connection manually - (2009-08-28)
  [3035] How to display information from a database within a web page - (2010-11-07)
  [3099] Perl - database access - DBD, DBI and DBIx modules - (2010-12-22)
  [3447] Needle in a haystack - finding the web server overload - (2011-09-18)
  [3455] MySQL, MySQLi, PDO or something else - how best to talk to databases from PHP - (2011-09-24)


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Some other Articles
The Farming Industry pictured around Melksham
They do weddings, we do courses.
Should Government compete with private industry?
Bath to Melksham buses - times
Joining a MySQL table from within a Python program
Melksham to London (Heathrow, and Central London)
Cost of Sales
Sleeping in on Sunday
The Light bulb moment when people see how Object Orientation works in real use
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This is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.

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