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 Yearling
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Jul
18
comment Primary key should be chosen so as attributes never change?
What is the relevance of saying the identity of an "entity" cannot change? By "entity" I understand you to mean "the thing about which information is recorded in the table". In practice the identifying attributes of things do sometimes change. In any case, the process and effect of changing keys is exactly the same whether you say a thing is the same entity afterwards or not. Enforcing immutability of keys is practically impossible in very many cases and unlikely to be helpful.
Jul
18
answered Primary key should be chosen so as attributes never change?
Jun
29
comment Is database normalization dead?
@Nupul, It seems very unlikely that the specified example of a surrogate key and a key consisting of an email address would be in violation of 2NF or BCNF. 2NF is violated only where there is a partial-key dependency.
Jun
8
awarded  Caucus
Apr
18
revised What normal form does a surrogate key violate?
expanded based on ypercube's comment
Apr
18
comment What normal form does a surrogate key violate?
5NF is "obscure"?! More to the point, the "nothing but the key" cliché isn't a very precise description of 3NF. 3NF is concerned equally with all the candidate keys of a relation, not just one. A surrogate key won't violate 3NF unless it gives rise to some partial key dependency. Most people will understand "surrogate" to mean a simple (non-composite) key consisting only of arbitrary values, so a partial key dependency involving a surrogate is extremely unlikely.
Apr
18
answered What normal form does a surrogate key violate?
Apr
16
revised Using an RDBMS for querying tens of Terabytes of time-series data?
The text of the question indicates that the title should be 10s rather than 10ths
Apr
16
comment Using an RDBMS for querying tens of Terabytes of time-series data?
Exadata, Netezza, Greenplum, etc. These are some of the popular SQL DBMSs for handling 10s or 100s of Terabytes of data.
Apr
16
suggested approved edit on Using an RDBMS for querying tens of Terabytes of time-series data?
Mar
31
awarded  Yearling
Mar
9
awarded  Necromancer
Feb
20
comment Would it be considered as a bad practice to have multiple nullable FKs on a table in SQL Server
One nullable foreign key is one too many.
Feb
20
answered Would it be considered as a bad practice to have multiple nullable FKs on a table in SQL Server
Feb
17
awarded  Tag Editor
Feb
6
answered What computations can NOT be performed in standard SQL?
Jan
25
comment Shrinking log file
If your log files are growing regularly then shrinking like that is a massively counter-productive thing to do. Don't do it. By doing this you are invalidating the log backup sequence. My guess is you are using FULL recovery when you might be better off using SIMPLE.
Jan
25
comment Is an anomaly free relation necessarily normalized?
If "all normal forms" includes DKNF then the answer is no. A relation in 6NF does not have undesirable update, insertion or deletion anomalies in the usual sense but it still may not satisfy DKNF. On the other hand DKNF is not very important and is frequently irrelevant or unachievable.
Jan
20
awarded  Nice Answer
Jan
11
answered why doesn't time for a simple update scale linearly with the number of records?