What is annoying in power supplies.

The thing that annoys me often are cables.  Network cables, USB cables. But the worst are power supply cables, and AC's. There are many small devices, each taking a few wats, but each must have its own power supply cable and very big AC. It's a hard task to plug all of them. Big plugs simply collide.

There is a modem, router and wireless phone, that is 3 AC's. And handy charger (4), and battery charger (5). 

Would be that so hard to develop one standard for supplying power to small devices? There could be then one AC with small cables for all devices plugged into it (such as network cables to switch).  Such universal power supply could contain battery charger and could be less power-consuming.

I would be most pleased having such a device:

A wireless VOIP router connected to wireless handset (I have VOIP router and wireless phone as separate device, with phone cable connecting them and surplus power supply cable), containing slots for charging batteries and sockets to plug in power cables to other devices (such as handy charger etc.). 

I thing USB gadgets are so popular because they do not require additional power supply :)

Every AC means surplus power consumption, and additional costs. Computer-dependend devices such as monitors and printers could also drain power they need directly from computer's AC, optimally via the same cable they send data, so there would be another cable less.

Oracle & temporal types

When considering Oracle temporal types, most people think of TIME type and DATE type (which is date + time).

I was a bit suprised to find out that Oracle 10 supports INTERVAL type and temporal operator OVERLAPS.

Intervals are quite simple. There is INTERVAL DAY TO SECOND and INTERVAL YEAR TO MONTH support. 

Example:

INTERVAL '5' DAY is 5 days.

INTERVAL '5 01:00:00' is 5 days and 1 hour.

INTERVAL '1' YEAR is one year.

INTERVAL '1-2' YEAR TO MONTH is one year and 2 months.

INTERVAL '12' MONTH is 12 months.

I don't know what is INTERVAL YEAR TO MONTH for. In what case when operating on ISO dates one year would be something different from 12 months. The most interesting, in my opinion, would be INTERVAL MONTH TO DAY and INTERVAL MONTH TO WEEK, because operating on days/weeks and months simultanously is the most problemating.

OVERLAPS operator is less interesting. It can be used only in WHERE clause and returns true when 2 periods, defined as (date-from, date-to), overlaps.

When overlapping is considered, periods are defined as exclusive sets

so (date '2009-01-01', date '2009-01-10') OVERLAPS (date '2009-01-10', date '2009-01-20') is NEGATIVE. Inclusive treating of periods by OVERLAPS operator would be very problematic to handle, considering we operate on timestamps. However, when we treat DATE field as date (not date with time) and take care that time part is '0', OVERLAPS is not very handy. From my operations, it does not make temporal queries more effective.