Things to chase after

MySQL specific?

select make_set(255,’bit0′,’bit1′,’bit2′,’bit3′,’bit4′,’bit5′,’bit6′,’bit7′);

select (1,2,3)=(1,2,3);

MySQL FULL OUTER JOIN

But the first two joins—the inner join, and the left exclusion join—are logically equivalent to a left outer join, so we can write:


SELECT * FROM a LEFT JOIN b ON a.id=b.id
UNION ALL
SELECT * FROM a RIGHT JOIN b ON a.id=b.id WHERE a.id IS NULL;

+------+------+------+------+
| id   | name | id   | name |
+------+------+------+------+
|    1 | a    | NULL | NULL |
|    2 | b    |    2 | b    |
|    1 | a    | NULL | NULL |
| NULL | NULL |    3 | c    |
+------+------+------+------+

Why doesn’t MySQL implement FULL OUTER JOIN syntax for this? We don’t know.

via Common Queries Tree.

When was your last restore?

But let’s stop talking about “backups.” Doing a backup is too low a bar. Any experienced system administrator will tell you that they have a great backup plan, the trouble comes when you have to restore.

via Let’s stop talking about “backups” – Joel on Software:

Twice in October on the home machine – dead internal drive.

The 2 major websites moved off of our servers, but before they moved I did a test restore every 4-5 months.

The Duct Tape Programmer

Sometimes, you’re on a team, and you’re busy banging out the code, and somebody comes up to your desk, coffee mug in hand, and starts rattling on about how if you use multi-threaded COM apartments, your app will be 34% sparklier, and it’s not even that hard, because he’s written a bunch of templates, and all you have to do is multiply-inherit from 17 of his templates, each taking an average of 4 arguments, and you barely even have to write the body of the function. It’s just a gigantic list of multiple-inheritence from different classes and hey, presto, multi-apartment threaded COM.

via The Duct Tape Programmer – Joel on Software.

Database Archiving Basics

Database archiving is becoming an important new topic for data managers. The need for this function has surfaced at most IT organizations, and the problems it addresses are only getting bigger and bigger. These problems include challenges with data retention requirements, application renovations and e-discovery. Most IT data managers recognize the problems but many do not associate database archiving as a solution. This will change as the technology matures and spreads.

via Database Archiving Basics.