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Nov
25
revised Platform independent select ordered by primary key
added 935 characters in body
Nov
25
revised Platform independent select ordered by primary key
deleted 1 characters in body
Nov
25
answered Platform independent select ordered by primary key
Nov
1
comment If all variables are a subset of the candidate key, is the database design 5NF?
Damir, you are right and my answer is wrong. I don't know what I was thinking of - BCNF maybe. Thanks anyway.
Oct
31
comment Is normalization process needed?
Perhaps it would be better to say that we should normalize the logical structure of the database. The phrase "logical model" is often (mis)understood to mean merely a preliminary design for a database rather than something actually existing in a database system. The important point surely is that what you implement ought to be normalized, not just what you sketch on paper :)
Oct
15
comment SQL Server transaction log file size and auto grow
When did you last back up the log? That is what determines the lifetime of the log. You should back up the log more often than you take full backups. Check that your log backups are working as you expect.
Oct
15
comment SQL Server transaction log file size and auto grow
SQL Server works similarly to Oracle. If you back up the log the space will be reused. If you have already backed up the log then create a new log file to make more space.
Jul
31
awarded  Nice Answer
Jun
16
comment how to convert a table into second normal form
Without any explanation of what dependencies the table is supposed to satisfy all anyone can do is make guesses based on the attribute names.
May
13
awarded  Caucus
May
10
answered Can a surrogate key and a primary key be in the same table?
May
2
answered Database design - People and Organisations
Mar
31
awarded  Yearling
Dec
4
comment The four properties of a primary key
Perhaps you were taught wrong. Those four conditions are neither necessary nor sufficient to make a key. Keys must be irreducibly unique (a minimal superkey) and non-nullable. Non-partial dependence is a requirement of 2nd Normal Form but not a fundamental requirement of keys. Indexing also has nothing to do with whether a set of attributes qualify as a key or not.
Aug
29
comment Why should a CTE start with a semi-colon?
"Why should a CTE start with a semi-colon?" In Standard SQL every statement is supposed to end with a semi-colon. The problem is that T-SQL only enforces that rule in a few places and one of those is for any statement that comes before a CTE. If there is no statement before WITH then you don't need ;.
Jul
18
comment Primary key should be chosen so as attributes never change?
You can't have read what I wrote. I was not "praising" anything. I've certainly changed surrogate key values plenty of times. In fact I'm surprised if you haven't encountered the need to update surrogate keys. Anyway, the question is about keys in general, not just surrogates. If you meant your answer to apply only to surrogate keys then you ought to say so.
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