Category: postgresql

Database Meets Revision Control

Any developer who has worked with HIPAA compliancy knows that the law is murky at best and the fed doesn’t publish a programmers’ guide to make your life any easier.  However, one of the cardinal rules is the requirement to keep track of who sees HIPAA data, who modifies it and when this was done.  Another is that if you delete/update patient data you need to log what was deleted/updated in order to provide an audit trail, if only for

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Optimizing a Result Set Pager

It’s ubiquitous on data driven web sites: the result set pager.  We’ve all used them whether we built them from scratch or used one provided by the framework. Pagers are by nature performance suckers because we’re asking the database to re-run the same query for each “page”, slicing off just one set of contiguous rows for each page. If your result set is 10,000 rows long but you’re only paging through them 10 rows at a time, that’s potentially 1,000

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Finding duplicate records in a database: the SQL HAVING clause

One issue I run across occasionally is a table with duplicate entries such as two entries for the same company in an accounts payable system.  This can create embarrassing problems with billing if ACME Inc #1 is 90 days overdue because someone credited a payment, and now a credit, to ACME Inc #2. I ran across this problem recently on a health records system which was missing a UNIQUE constraint on a secondary patient ID field: student ID.   The

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