Monthly Archives: October 2006

Experience with Derby

I have been playing around with Derby for quite sometime for an application that contains an embedded web server and an embedded database! Yes, I am trying to create an app that has both components embedded.

I initially tried using Derby as a pure embedded mode but didn’t work as my application required concurrent access. So, I am running it in Networked server mode that starts within the embedded web server. So far no issues and it seems to perform quite well.

Couple of issues I ran into with respect to the SQL support in Derby are

1. Couldn’t delete a column from a table.
2. So, thought of copying everything into a temp table and creat a brand new table. However, the “create table xyz as select …” syntax doesn’t work.
3. It’s not possible to have multiple DISTINCT aggregate functions. Like, select count(distinct a),sum(distinct b) from abc”. However, in my specific case, I actually needed just one single distinct aggregate but used multiple times. Ideally, this optimization should have been built-in. But, I worked around this issue with an additional sub-select. Atleast, glad I can have multi-level nested sub-selects.
4. I wanted to convert a timestamp field and get the corresponding milliseconds out of it and so far I don’t see a way to do it in SQL. I probably select the timestamp and use java code to get the milliseconds, not sure.

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Filed under embedded databases, technical opinion

localhost & cookies

I figured out today the hardway that it’s not possible to set cookies with the domain name as localhost. After a bit of research, using a blank string (“”) whenever the domain name is localhost will set the cookie for the localhost.

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Filed under Tech - Tips

Simple and intuitive java swing layout manager

With all the web apps hype, I still think desktop apps have their place. But talking about it means digressing from the main topic. I had to create a simple Java Swing based form and after using GridBagLayout, my form was all ugly. So, after a bit of research for the alternate layouts, I came across this wonderful layout manager called
river layout which is an LGPL component and is less than 6kb. You can’t ask for more!

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Filed under Java GUI, Java Swing

Software Startup

Today I have been doing some research on starting a software company. One article I came across is

Running a Business On OpenSource Software

The good thing with open source or software as a service (SAAS) is that the startup costs can be drastically reduced.

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Filed under software startup, startups