Java Practices->Don't perform basic SQL tasks in code

Don't perform basic SQL tasks in code

Relational databases are a mature technology, and they should be used to do as much simple work as possible.

For example, don't do the following in code, if they can be done in SQL instead:

ordering (ORDER BY)
filtering based on criteria (WHERE)
joining tables (WHERE, JOIN) -- see the code tables topic for a possible exception to this rule
summarizing (GROUP BY, COUNT, AVG, STDDEV)

Any corresponding task implemented by your own code would very likely:

be much less robust and efficient
take longer to implement
require more maintenance effort

To retain the order of a ResultSet as specified in ORDER BY, choose a collection which has a defined iteration order, such as an ArrayList or a LinkedHashMap.