View MasterMap Change-Only Updates (Part 2)

By GGP Systems

Posted in Technology Blog on October 24th 2010 12:51

Following on from Part 1 of this post, I will now use display queries to differentiate the COUs using colour codes.

In order to do this, we need to remember the original COU date ranges:

  • From 15/12/2009 to 02/02/2010
  • From 02/02/2010 to 16/03/2010
  • From 16/03/2010 to 27/04/2010
  • From 27/04/2010 to 08/06/2010
  • From 08/06/2010 to 20/07/2010

With this information, we can create five display queries that make use of the SQL keyword between, assigning a different colour to each one:

  • VERSIONDATE between ‘2009-12-15 00:00:00’ and ‘2010-02-02 00:00:00’
  • VERSIONDATE between ‘2010-02-02 00:00:00’ and ‘2010-03-16 00:00:00’
  • VERSIONDATE between ‘2010-03-16 00:00:00’ and ‘2010-04-27 00:00:00’
  • VERSIONDATE between ‘2010-04-27 00:00:00’ and ‘2010-06-08 00:00:00’
  • VERSIONDATE between ‘2010-06-08 00:00:00’ and ‘2010-07-20 00:00:00’

It’s best to use the year-month-date hour:minute:second ISO 8601 format whenever we write queries that operate on date/time columns.

The results show clearly which areas were updated, and when:

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