I am creating a system which polls devices for data on varying metrics such as CPU utilisation, disk utilisation, temperature etc. at (probably) 5 minute intervals using SNMP. The ultimate goal is to provide visualisations to a user of the system in the form of time-series graphs. I have looked at using RRDTool in the … Read more
Disregarding performance, will I get the same result from query A and B below? How about C and D? — A select * from a left join b on <blahblah> left join c on <blahblan> — B select * from a left join c on <blahblah> left join b on <blahblan> — C select * … Read more
I’ve found the concept and meaning behind these methods to be a little confusing, is it possible for somebody to explain to me what the difference between has and with is, in the context of an example (if possible)? 2 Answers 2
I’m doing some research into databases and I’m looking at some limitations of relational DBs. I’m getting that joins of large tables is very expensive, but I’m not completely sure why. What does the DBMS need to do to execute a join operation, where is the bottleneck? How can denormalization help to overcome this expense? … Read more
Can anyone explain how to implement one-to-one, one-to-many and many-to-many relationships while designing tables with some examples? 4 Answers 4
What is the difference between Views and Materialized Views in Oracle? 8 Answers 8
Good Overviews Generally speaking, you’re making a decision between fast read times (for example, nested set) or fast write times (adjacency list). Usually, you end up with a combination of the options below that best fit your needs. The following provides some in-depth reading: One more Nested Intervals vs. Adjacency List comparison: the best comparison … Read more
