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Every programmer should embrace and use regular expressions (INCLUDING Database programmers). There are many places where regular expressions can be used to reduce a 20 line piece of code into a 1 liner. Why write 20 lines of code when you can write 1.

Regular expressions are a domain language just like SQL. Just like SQL they are embedded in many places. You have them in your program editor. You see it in sed, grep, perl, PHP, Python, VB.NET, C#, in ASP.NET validators and javascript for checking correctness of input. You have them in PostgreSQL as well where you can use them in SQL statements, domain definitions and check constraints. You can mix regular expressions with SQL. When you mix the two domain languages, you can do enchanting things with a flip of a wrist that would amaze your less informed friends. Embrace the power of domain languages and mix it up. PostgreSQL makes that much easier than any other DBMS we can think of.

For more details on using regular expressions in PostgreSQL, check out the manual pages Pattern Matching in PostgreSQL

The problem with regular expressions is that they are slightly different depending on what language environment you are running them in. Different enough to be frustrating. We'll just focus on their use in PostgreSQL, though these lessons are applicable to other environments.

PostGIS 1.5.0 is finally out

I'm happy to report that after a long haul, we have finally released PostGIS 1.5.0. Two months late, but there it is, and its a really great release I think; Perhaps the best release ever.

Details on what makes this release so special. The geodetic support.

Summary excerpted from Paul's slightly premature announcement

February 4, 2010

The PostGIS development team has, after a long course of reflection
and a detailed self-examination of our various personal failings,
decided to release PostGIS 1.5.0 to the public.

  http://postgis.org/download/postgis-1.5.0.tar.gz

This new version of PostGIS includes a new "geography" type for
managing geodetic (lat/lon) data, performance-enhanced distance
calculations, GML and KML format readers, an improved shape loading
GUI, and other new features as well.

Especial thanks to:

* Dave Skea for algorithms and mathematics necessary to support
spherical geometry
* Nicklas Avén for the new performance enhanced distance calculations
and other distance-related functions
* Sandro Santilli for new buffering features (end caps and style options)
* Olivier Courtin for GML/KML input functions
* Guillaume Lelarge for support for the upcoming PgSQL 9.0
* George Silva for an example implementation of history tables
* Vincent Picavet for Hausdorff distance calculations
* The maintainers of GEOS, Proj4, and LibXML, without whom we would
have less of a spatial database

Love, the PostGIS project steering committee,

Mark Cave-Ayland
Kevin Neufeld
Regina Obe
Paul Ramsey