Question

There is a need to update one field to the same value in a heap of records. Using the DAO/ORM structure, I would retrieve each parent object, loop through each child object, update it s field, and then save it.

It would be faster to just write the SQL: update table set field = value where criteria = specified.

How do I fit these things together? Do I just stick with the dao structure:

for (Table t : getTableDao().getTables()){  
  for(Child c : t.getChildren()){  
    c.setValue(1);  
    getChildrenDao().save(c);  
  }
}

Cheers.

Answer 1

In general, mass updates should not be done in what might be considered the "normal ORM" way, which is as you describe, looping through each object.

Any reasonable ORM has a mechanism for you to run a normal SQL update statement as you propose and that is generally the correct way to do it.

Just because you are using an ORM doesn t mean you can t take advantage of the relational set based system underneath. Use objects when objects make sense and use SQL when SQL makes sense.

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