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Finding rows in one table not present in another table with PostgreSQL

March 6th, 2010 by Mark · 2 Comments

In implementing a comprehensive SNOMED CT browser as part of a research clinical information system, I cache the results of several processor and disk-intensive queries to speed up lookup and SNOMED CT navigation. I was finding some odd results and found that my caching was missing for several items. I needed a way of comparing the contents of one table with another in PostgreSQL and finding out which rows were not present. [Read more →]

→ 2 CommentsTags: Databases

Executing raw SQL with WebObjects and Project Wonder

March 6th, 2010 by Mark · No Comments

WebObjects is an extraordinarily powerful java based web-application server. On occasions, I need to execute arbitrary SQL against the underlying database. This is not necessary for most uses, but for certain batch operations it is useful. [Read more →]

→ No CommentsTags: WebObjects

Recursive SQL with PostgreSQL 8.4

March 4th, 2010 by Mark · No Comments

Representing hierarchical data in a relational database is easy. For instance, modelling the contents of a filesystem with directories and subdirectories is straightforward using self-joins on a parent key. The root node(s) are represented as those without a parent. Such a model is useful for modelling other types of data - in particular, hierarchies in which nodes can have multiple parents - for example, SNOMED CT is a hierarchical clinical terminology - the “Systematised Nomenclature of Medicine Clinical Terms”. The Connecting for Health website suggests this terminology is in widespread use by “all computers” in the NHS (website accessed 4th March 2010) but as those of us who work in the NHS will testify, this is not the case. [Read more →]

→ No CommentsTags: Databases · Medical

More posts

March 4th, 2010 by Mark · 1 Comment

After a long hiatus while we both finish our theses (one of us [1] more successfully than the other) and obtain substantive posts (one of us [2] more successfully than the other), we are keen to restart regular nerdy medical technology posts.

Welcome back!


(1) Completed his MD in 2008
(2) This is not necessarily the same person

→ 1 CommentTags: Medical · Research

Encrypting a USB Key using TrueCrypt

October 26th, 2008 by James · 20 Comments

If you are a healthcare professional you have a duty to maintain the security of patient identifiable data. Within your job you sometimes need to use a USB key to transfer lists or letters between computers. If you lose your un-encrypted USB key with patient identifiable data then it may deemed negligent and you may face disciplinary action. In this how-to I will talk through how to setup an easy to use secure software encryption scheme for a USB stick/key for use with Windows. [Read more →]

→ 20 CommentsTags: Free · Medical · Open Source · Software

How to encrypt ZIP files securely using 7Zip

October 18th, 2008 by James · 10 Comments

Windows has had built in zip file support with encryption since Windows XP, unfortunately the quality of this encryption is poor as evidenced by the number of commercial programmes available to crack it. Winzip, WinRAR are trialware commercial programs that offer secure AES encryption to your compressed files but cost between 23 and 30 Euros per user. 7-Zip is an open-source, free utility that offers AES-256bit encryption. In this how-to I will show you how to install and produce 256-bit encryption of your compressed files. [Read more →]

→ 10 CommentsTags: Free · Open Source · Software

Filling in PDF Forms with Foxit PDF Reader

August 16th, 2008 by James · 5 Comments

Foxit PDF Reader is a free closed source alternative to Adobe’s PDF reader. On older machines it feels snappier than using Adobe’s bloated product. In this short how-to I will show you how to fill in forms using Foxit Reader with the 39 US$ Pro-Pack. [Read more →]

→ 5 CommentsTags: Software

Custom LaTeX bibliography style files: Part 2/4

March 22nd, 2008 by Mark · 6 Comments

In this article, I will show the steps involved in creating a bibliography style file for the Journal Brain and include the relevant BST file for LaTeX, a powerful typesetting system available for all common platforms, including Windows, Linux and Mac OS X.
[Read more →]

→ 6 CommentsTags: LaTeX

How to make a UK map for TrekBuddy

February 2nd, 2008 by James · 21 Comments

Sometimes you wish to use your GPS and data enabled mobile phone to navigate but either you do not have a data signal, or the map you require is not available through Google or BlackBerry maps. This short article will talk you through how to create a map to be used with TrekBuddy on your mobile, PDA or BlackBerry.

[Read more →]

→ 21 CommentsTags: BlackBerry · Free · Software

How to install offline Maps on your BlackBerry using TrekBuddy 0.973

February 2nd, 2008 by James · 71 Comments

BlackBerry smartphones are handy for GPS navigation helped by the excellent BlackBerry and Google Maps applications. When you are out of range of a data signal both these applications are unable to continue to provide a map. With TrekBuddy you can use offline maps, from Google and elsewhere, record route speed and waypoints, or use your phone as a direction finder. TrekBuddy is a great, freeware application developed by Kruch a Czech developer and is suitable for J2ME devices including a BlackBerry with OS 4.1 or greater.

[Read more →]

→ 71 CommentsTags: BlackBerry · Free · Software