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For 2021 - online Python 3 training - see ((here)).

Our plans were to retire in summer 2020 and see the world, but Coronavirus has lead us into a lot of lockdown programming in Python 3 and PHP 7.
We can now offer tailored online training - small groups, real tutors - works really well for groups of 4 to 14 delegates. Anywhere in the world; course language English.

Please ask about private 'maintenance' training for Python 2, Tcl, Perl, PHP, Lua, etc.
Factory methods and SqLite in use in a Python teaching example

I've just uploaded a neat little example - [here] from last week's Python course - it's amazing what you can do in a very few lines of code.

The application scenario is that we have a database of customers - some are residents at our hotel and others are delegates on our courses. Being mercenary folks, our accounting team wants to work out the income for a selection of customers ... and the algorithms are different for residents and delegates, even though many of the properties (a.k.a. attributes) of both groups (a.k.a. subclasses) of customer are handled identically.

Some interesting features of the demo ...

• I have used SqLite as my database engine. For small to medium sized database requirements, SqLite is excellent and growing. It's shipped with modern versions of Python, it's good, and it avoids the need for an extra level of process - a database daemon - that you'll get with MySQL or Oracle. The database can be accessed from "any" language - not just Python - and it transactional across concurrent applications (which other daemonless databases are not).

• As records are read off the database, the may pertain to either customer type - and I have used a static factory method to build my new objects, allowing me to simply pass in the data from the database to a piece of code that's maintained with the classes themselves and have it return a new customer object of the appropriate subtype. There is no need for my main application (and it would not be desirable) to get involved in the detail of working out what type of customer each record pertains to as it comes off the database.

(written 2010-05-29, updated 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)
  [2790] Joining a MySQL table from within a Python program - (2010-06-02)
  [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)

S200 - MySQL - SQLite
  [2561] The future of MySQL - (2010-01-03)
  [2744] PyQt (Python and Qt) and wxPython - GUI comparison - (2010-04-28)
  [3099] Perl - database access - DBD, DBI and DBIx modules - (2010-12-22)
  [3269] Files or Databases? MySQL, SQLite, or Oracle? - (2011-04-28)
  [4006] Ruby / SQLite3 example program, showing JOIN v LEFT JOIN - (2013-02-16)
  [4007] Which database should I use? MySQL v SQLite - (2013-02-16)

S151 - Introduction to SQL and MySQL
  [84] MySQL - nuggets - (2004-10-11)
  [85] Present and future MySQL - (2004-10-12)
  [175] Worthwhile - (2005-01-11)
  [382] Central London Courses - Perl, PHP, Python, Tcl, MySQL - (2005-07-18)
  [444] Database or Progamming - which to learn first? - (2005-09-13)
  [515] MySQL - an FAQ - (2005-12-03)
  [591] Key facts - SQL and MySQL - (2006-02-04)
  [691] Testing you Perl / PHP / MySQL / Tcl knowledge - (2006-04-19)
  [918] Databases needn't be frightening, hard or expensive - (2006-11-08)
  [924] The LAMP Cookbook - Linux, Apache, MySQL, PHP / Perl - (2006-11-13)
  [2134] Oracle take over Sun who had taken over MySQL - (2009-04-21)
  [2567] Extra MySQL course dates (2 day course, UK) - (2010-01-08)
  [3928] Storing your intermediate data - what format should you you choose? - (2012-11-20)


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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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