example of SQLite using a local database file through SQLalchemy

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Here's an example of SQLite using a local database file through SQLalchemy. The SQL statements are hidden from the user - that's the "Object to Relation Mapping" - although you can ask what's going on by runing my program with a -v option. ... example program source [here], seeding data download from [here].

We start by seeing if the database file exists:

  database = "stations.db"

  populated = os.path.exists(database)

So that we only have to populate the tables if they don't exist (we have a seeding data file).

Here's output from a typical run:

  WomanWithCat:flask grahamellis$ python orm_sqlite

  Station (code='MKM', postcode='SN12 8BN', footfall='23930', fullname='Melksham')

  (u'TEA', 8, u'Tees-Side Airport')

  (u'SPP', 12, u'Shippea Hill')

  (u'RDS', 26, u'Reddish South')

  (u'BYL', 40, u'Barry Links')

  (u'COE', 42, u'Coombe')

  (u'BRC', 64, u'Breich')

  (u'BUC', 80, u'Buckenham')

  (u'PIL', 88, u'Pilning')

  (u'GOF', 90, u'Golf Street')

  (u'DTN', 110, u'Denton')

  (u'KTL', 120, u'Kirton Lindsey')

  (u'ABC', 138, u'Altnabreac')

  (u'KIL', 144, u'Kildonan')

  (u'ELO', 166, u'Elton & Orston')

  (u'ACK', 176, u'Acklington')

  (u'AAT', 228, u'Achanalt')

  (u'CPN', 232, u'Chapelton')

  (u'SUG', 240, u'Sugar Loaf')

  (u'HEL', 276, u'Hensall')

  (u'HVN', 278, u'Havenhouse')

  (u'CLI', 298, u'Clifton')

  (u'SNT', 314, u'Stanlow & Thornton')

  (u'RWC', 314, u'Rawcliffe')

  (u'HBB', 334, u'Hubberts Bridge')

  (u'TPC', 340, u'Thorpe Culvert')

  (u'NCE', 348, u'New Clee')

  (u'SCT', 376, u'Scotscalder')

  (u'LAK', 378, u'Lakenheath')

  (u'SPN', 388, u'Spooner Row')

  (u'FOC', 498, u'Falls Of Cruachan')

  WomanWithCat:flask grahamellis$

(written 2015-10-14)

Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles

Y113 - Python and SQL databases
  [2745] Connecting Python to sqlite and MySQL databases - (2010-04-28)
  [2746] Model - View - Controller demo, Sqlite - Python 3 - Qt4 - (2010-04-29)
  [2786] Factory methods and SqLite in use in a Python teaching example - (2010-05-29)
  [2790] Joining a MySQL table from within a Python program - (2010-06-02)
  [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)

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