This way all applications are
dealing with the same rules and can reasonably expect the data to be in the same format
regardless of its originating source.
CHAPTER 4 ?– CORE FEATURES OF ACTIVE RECORD 81
This last implementation option really shines a light on the main design decision you
have to make when thinking about implementing data validations??”do you implement them
in Ruby or directly in your database? Before you make your choice, consider these pros and
cons of Active Record validations:
??? Pros: The good news is that because Active Record objects are really just Ruby objects,
Active Record validations are database independent. You don??™t need to know any special
syntax or language such as TSQL or PL/SQL; you just write Ruby methods with
Ruby code. Additionally, the validations occur on the object before data gets mapped
to the database via SQL calls, which means that you save expensive (in terms of bandwidth
and processing) database calls for just those times that you really want them.
??? Cons: The bad news is that Active Record validations are only applied within your Ruby
code.
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