6,780 reputation
1923
bio website mooseware.ca
location Mississauga, Canada
age 52
visits member for 3 years, 3 months
seen 6 hours ago

I'm a professional software developer with more than twenty years of experience across many industries and the entire systems development lifecycle. I'm the principal consultant at Mooseware Limited.

@joelabrown

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Jun
29
answered Best relationship database design to manage types for different entities
Jun
27
comment Different type of column
@yannis - Hmmm, hard to find a really great link. The terminology is what's used in James Martin's Information Engineering(TM) method. Some others call it a classifying attribute. The topic to read up is Entity Subtyping - this will cover the various ways that you could implement this model physically. The point of the partitioning attribute is to help enforce mutual exclusivity of subtypes. Each subtype is associated with a particular data value in the partitioning attribute.
Jun
26
answered Different type of column
Jun
26
comment Reviewing relational database tables
You need to think about (or state, if you know them) what your candidate keys are. What is the business key of your students_class table? It looks like it may not be normalized to me. Ask your friend what is the purpose of the additional table? All of the information it contains is already available in the other tables and can be retrieved through query or view.
Jun
23
answered Entity Relationship Model - double one to many
Jun
8
answered Train Fare Database Normalisation
May
30
answered How to store list of unknown size in database
May
29
comment Optimum design / structure for product data database?
Have a look at my answer to this question, which addresses your requirement for product attribute values: stackoverflow.com/questions/14194841/…
May
29
comment Optimum design / structure for product data database?
Also, see my answer to a very similar question on SO: stackoverflow.com/questions/11779252/…
May
29
comment Optimum design / structure for product data database?
There should be a third table containing attribute names so that a comparison can be made across products. This is called Entity Attribute Value and is generally frowned upon, but I consider it to be the perfect for product catalogs. See: stackoverflow.com/questions/11779252/…
May
29
comment Optimum design / structure for product data database?
This question has been asked before, and not necessarily appropriately, closed as being primarily opinion-based. See dba.stackexchange.com/questions/49432/…
May
29
comment Optimum design / structure for product data database?
possible duplicate of Which schema is better for a shopping project?
May
26
awarded  database-design
May
25
revised Is this many to many relationship correct?
Made explicit the differences between DMBS with and without DEFERRABLE.
May
25
answered Is this many to many relationship correct?
May
25
comment Should I split these fields or leave as one?
@LeoKing - Yes, precisely. If you have a separate column for house name then you can easily query that way. If on the other hand you kept everything in one combined name field, then you'd be down to using WHERE name like '%stark%' which is always problematic for various reasons.
May
25
comment Should I split these fields or leave as one?
@LeoKing - You could start with one table and then decide later if you want to create tables for additional details beyond the character, such as books and houses. Keeping these potential "foreign keys" separate from the outset will save you retyping your data later and it will simplify querying the data, such as "show me all the Starks".
May
25
comment Should I split these fields or leave as one?
@LeoKing - Blank space is a problem if you have many, many nulls per row or if you have an enormous number of rows or if you have tiny, tiny hard disks. For a table with a dozen columns and a few hundred rows (or even thousand) the amount of "wasted" space isn't going to be worth creating an elaborate technical work-around. I would say: trade off a few KB of hard disk for much simpler, more maintainable code.
May
25
answered Should I split these fields or leave as one?
May
24
answered Why do we not store names in a separate table?