May 202013
from   data_models dm
join   data_model_values qc
on = qc.model_id
join   data_model_values de
on = de.model_id
join   data_model_values coa
on = coa.model_id
where  qc.attr = 'Query complexity'
and    qc.val = 'Hideously mind-boggling'
and    de.attr = 'Datatype enforcement'
and    de.val = 'Non-existent'
and    coa.attr = 'Calculation of aggregates'
and    coa.val = 'Almost impossible';


select name
from   data_models
where  query_complexity = 
         'Simple and straightforward'
and    datatype_enforcement = 
         'Strong and complete'
and    calculation_of_aggregates = 
         'As easy as group by';


While it's possible to end up with some dodgy queries and datatypes in a "normal" relational model, 
it's much easier to fix the problems when compared to EAV. If you've got any other comparisons 
between EAV and normal relational models, please add them in the comments!

To be fair, there are (very) few cases where EAV is appropriate. This provides a nice discussion of when you should/shouldn’t use this.

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