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Constraints are business rules of which the logic
is specified in SQL. One type of constraint, the restrictive
constraint, specifies which data is allowed to go into the
database, and which not. The Rules Engine checks validity of
database transactions against the USoft Developer repository
containing the constraint specification. If a transaction violates
the rule it is rejected.
Another type of constraint is
the corrective constraint. Corrective constraints themselves
manipulate data in the database. These manipulation attempts are
also checked by the Rules Engine.
SQL select statements executed
in the process of constraint evaluation are executed by the Rules
Engine regardless of the authorization settings.
On the other hand, insert,
delete and update statements are only actually executed if
appropriate manipulation rights have been specified.
In short, you need data
manipulation rights (delete, insert, and update rights) to have the
Rules Engine perform manipulations on the data as a result of
corrective constraint firing, but you do not need rights to have
the Rules Engine evaluate restrictive constraints.
For more information on
constraints, read the chapter on "Constraints" in the USoft Definer
Guide.
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