David.Poole

Graph databases are ones where I feel there is a lot of potential but now we have graph capabilities in SQL Server. I think we need some really good examples...

a relational store is likely better

It is important to remind everyone that a relational DBMS is not a way of "storing" data. The relational model provides a logical interface to...

Dr Codd described a relation in a way that described what we think of as a record or tuple

A relation (in the relational model) is more equivalent to a table...

Although ERD are typically used to visualize relational models, it could also apply to multi-dimensional and other models, so long as you have a more flexible definition of what an...

Despite the apparent complexity at the mathematical level

The mathematical level is much simpler than SQL. The mathematical definition of a function is much simpler than the programming language definition -...

any restrictions on the level of temporal resolution

Is there ever a business case for having the time expressed down to microseconds? I recommend reading Flash Boys - A Wall Street...

• This reply was modified 3 years, 3 months ago by  will 58232.

It just because data is related to other data.

Codd called his invention relational because it is based on the mathematical construct of a relation. This represents a relation between sets....

• This reply was modified 3 years, 3 months ago by  will 58232.
• This reply was modified 3 years, 3 months ago by  will 58232.
• This reply was modified 3 years, 3 months ago by  will 58232.
• This reply was modified 3 years, 3 months ago by  will 58232.

Anyone yet to take me up on explaining why a relational DBMS is called "relational"? It's a pretty fundamental question for a DBA.

CURRENT_TIMESTAMP is an ISO Standard supported by Oracle and DB2 so that's not an excuse.

Which would explain why they don't know about getdate() - thanks by the way, I prefer...

would you actually want to hire someone that claims to know T-SQL if you ask them how to get the current date and time using T-SQL and they HAVE to...

Ask them about real situations or problems. See if they teach you anything or approach a problem in a better way. See if they bother to ask me for more...

Some more questions for the senior candidate

What do you understand by closure in a relational context?

What transformation rules would you apply to simplify queries and check constraints?

What answer are YOU looking for?

Why is it called relational?

Ask someone if they know why an RDBMS is called relational.

Is no one going to take the bait?

Ask someone if they know why an RDBMS is called relational.

The majority of candidates will give the wrong answer. This doesn't mean they should be rejected - they just need...