Sql
Course review: SQL …
Update: Markus was kind enough to comment on my review. Regarding the "minimise the number of tables to limit joins" he said:
it is often the best approach to store some attribute redundant (e.g. normalised as before plus wherever needed). Maintenance of this redundancy should be …
Two less common tricks …
Recently I faced an SQL performance issue. What I wanted to do was rather common: Apply the (set) difference operation on two tables.
In relational algebra, the difference operation applied on two tables A and B gives as a result a new table C that contains all the elements that are in table A but …
In relational algebra, the difference operation applied on two tables A and B gives as a result a new table C that contains all the elements that are in table A but …
Book review: SQL …
In SQL Antipatterns, Bill Karwin does a great job in explaining how to make efficient use of the relational model, instead of abusing it like it's usually done. Many developers abuse relational databases using antipatterns such as ID required, entity-attribute-value, index …