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Mar
31
awarded  Yearling
Feb
11
awarded  Good Answer
Dec
26
revised What is Atomic Relation in First Normal Form
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Nov
19
answered Is it possible to get rid of so-called 'Spurious Tuples' completely?
Nov
4
answered How to satisfy 2NF and what are superkeys? - Understanding the algorithm for database normalization in general
Nov
4
comment Is it a good idea to use a personal number as a primary key for a customer table?
Identifying customers with a customer number is not "generally" bad practice! It's pretty much essential practice in many scenarios. You are just guessing that the number in question is a social security number or a phone number and on that basis you are claiming it is "bad".
Nov
4
answered Is it a good idea to use a personal number as a primary key for a customer table?
Oct
23
awarded  Altruist
Oct
22
awarded  Investor
Oct
12
answered If a table with a surrogate key has a column known to have unique non null values (eg SSN), does it violate 3NF?
Sep
27
revised Explaining 2NF vs 3NF with an example
added 90 characters in body
Sep
25
answered Explaining 2NF vs 3NF with an example
Jul
27
awarded  Caucus
Jul
10
revised Why should a key be made explicit?
added 10 characters in body
Jul
10
answered Why should a key be made explicit?
Jun
28
comment SQL Server vs Oracle
This might help.
Jun
10
comment Is it acceptable to have circular foreign key references\How to avoid them?
@Pieter, 1-1 isn't the only example of a join dependency, and it's not even a particularly special case. There are cases where join dependency constraints make perfect sense.
Jun
10
comment Is it acceptable to have circular foreign key references\How to avoid them?
@Pieter, Enforcing join dependencies is not something you would ever recommend? Why? What do you have against data integrity constraints?
Jun
3
comment Is it acceptable to have circular foreign key references\How to avoid them?
Leaving aside the specifics of any one example, in general terms there is nothing necessarily wrong or "flawed" about having reciprocal (i.e. "circular") referential integrity constraints. This is in effect just an example of a Join Dependency. Join dependencies are a good thing in principle if your DBMS allows you to implement them. It's just that in SQL DBMSs it isn't very easy to implement complex dependencies between tables.
Jun
2
comment Three questions about Database design
Why would you want to allow duplicate user names? I think that most social networking sites don't allow that.