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Apr
19
comment Unsure how to implement certain constraints and relations in this relational database schema
MySQL doesn't enforce CHECK() constraints. Sometimes, you can replace a CHECK() constraint with a foreign key constraint. (But not this time.) The only practical way to implement "arrival city is different from departure city" in MySQL is with a trigger.
Apr
19
answered PostgreSQL and default Schemas
Apr
17
comment How to permanently delete a row in oracle forever
Define "ever". Are we allowed to recover deleted data by restoring from a year-old offsite backup tape?
Apr
17
answered In Postgresql, is it possible to change the maximum number of columns a table can have?
Apr
16
comment Database design: Dividing multiple identical tables, good or bad?
Yes, more tables for more referential integrity. (But there's no "areas" table. There could be, though.) Usually you trust the local admins to a certain extent. They have a vested interest in being careful. People who take reservations over the phone wouldn't have insert or update permissions on "seats".
Apr
15
comment Database design: Dividing multiple identical tables, good or bad?
If you're confident in your data entry people, you can drop the check constraint for "area". In general, the more "flexible" your situation, the more tables you need to keep out bad data.
Apr
15
revised Proper indexes or anything else to optimize
Faster hardware.
Apr
14
comment Database design: Dividing multiple identical tables, good or bad?
Thank you, Sid. I hope you know that I'm going to quote you on my CV.
Apr
14
awarded  Enlightened
Apr
14
awarded  Nice Answer
Apr
14
answered Proper indexes or anything else to optimize
Apr
14
comment speeding up a query on MySql
Which columns are varchar(200)? The source columns or the target columns? GROUP BY on 10 million rows will probably take a while.
Apr
14
revised Database design: Dividing multiple identical tables, good or bad?
Extended examples.
Apr
14
revised Database design: Dividing multiple identical tables, good or bad?
Extended examples.
Apr
14
answered Database design: Dividing multiple identical tables, good or bad?
Apr
13
comment Functional Dependencies and Normal Forms
Are you being asked to determine the normal form for the relation R{ WX Y Z }, or the normal forms for { WX Y }, { WX Z }, and { Y Z }? (When you write "determine the form of:...", the of usually refers to whatever comes after.)
Apr
12
comment How database administrators can see my requests to SQL Server?
"Is there any other ways to see my activity?" Who cares? Are you trying to keep your activity a secret from the sysadmins?
Apr
11
comment Column or new table
Third normal form has to do with transitive dependencies. It has nothing to do with whether you store a school's name or its id number. (ID numbers have nothing to do with normalization.)
Apr
11
comment IP Address lookup star schema design
If I were in your shoes, I'd also want to test MySQL performance against PostgreSQL and its inet or cidr data type.
Apr
11
comment DB2 PureScale on Linux
I think asking IBM would give you a more actionable answer.