Recently I was working on an RSS feed aggregator – a SQL Merge statement that through the use of httpuritype and XMLTable scans multiple RSS feeds and merges the news items from those feeds into a central RSS_ARCHIVE table. I soon discoveredthat the archive would become flooded with stories on the candidates for the US elections. So I decided I would ban those articles from the RSS_ARCHIVE table: I would not allow any article that had the name of one of the four contenders (President and Vice President) in its title. And the easiest way to enforce such a record level constraint obviously is a Check Constraint. (more…)