Month: December 2016

Computer science and programming interviews

Recently my friend Janie has done a series of blog posts on her disagreement with using computer science questions as a major part of the hiring process. I can agree with her, to a point. If you’re hiring for someone to do a specific job using a specific language or framework, and the person being interviewed can demonstrate experience with and competence in that language or framework, then that’s probably as far as you need to go. You have a job that needs to be done and you’ve found someone who can do that job. Win! I think that when the job is less well-defined is when algorithms questions can more usefully come into play. But let me back up and relate a few stories from my personal experience. As a GTA (graduate teaching assistant) part of my job was to monitor the computer lab and help people as needed. The undergraduate classes at my school used Java; I don’t, but I grabbed a book and picked up enough of it to be able to get people unstuck. I guarantee that pretty much everyone I helped had much more experience with and knowledge of Java than I did – they were using it every week for their classes, while I’d picked up the bare minimum to be able to read it. But I was getting people unstuck because they...

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Oracle, index-organized tables, and overflow tablespaces

SQL Error: ORA-25191: cannot reference overflow table of an index-organized table

A refresher: a SQL database is relational, and rows are stored unsorted; Oracle calls standard tables heap-organized tables. For a given SQL query, unless an ORDER BY clause is used, results can be returned in any order. Oracle also has IOTs, which are tables that are instead stored in a B*Tree index structure. This structure stores all columns of the table, sorted by primary key; because this is both the table and the index, accessing rows is much faster and less storage space is needed than for a heap-organized table with a separate index.

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On Writing, Learning, and More

The problem with having a blog is that you have to post new content pretty consistently, or else it becomes just one of the 70 zillion sites on the internet that never gets updated and nobody reads. The question is, how do you always manage to have something to say on a (weekly or better) basis? This becomes more difficult when it’s a professional blog rather than a personal one. I could certainly write a few posts about my amazing sabbatical in Europe (if you have any interest at all in history and/or castles and have the opportunity to...

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