New Topic: Should 'or precondition's be Short Circuited (aka Lazy Evaluation)?

[Nathan Voxland-3]

A new topic, 'Should 'or precondition's be Short Circuited (aka Lazy Evaluation)?', has been made on a board you are watching.

You can see it at
http://liquibase.org/forum/index.php?topic=145.new#new

The text of the topic is shown below:

Should orpreconditions be short circuited?

As it is, you cannot have pre-conditions like "only run if this table is missing OR, if it exists, check that it contains a particular record".

e.g.

Code:
<precondition>
  <or>
    <not>
      <tableExists tableName="some_table"/>
    </not>
    <sqlCheck expectedResult="0">
      SELECT MAX(id)
      FROM some_table
    </sqlCheck>
  </or>
</precondition>


However, if orprecondition's were short-circuit and evaluated in the order that they appear, then once one condition evaluates to true, you do not need to continue evaluating other conditions in the or block.

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Regards,
The LiquiBase Community Forum Team.
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