Database Reference
In-Depth Information
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Equal (=)
. The keys on both sides of the relationship match exactly. This is the most
common type of relationship.
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Not Equal (≠)
. All records but those with matching keys relate to one another. You just
saw a good example: You want to show all related invoices except the one you're view-
ing. This operator is most often used in conjunction with another criterion.
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Less Than (<)
. Keys in the table on the left side of the dialog box have to be less than
keys in the table on the right side. Use this operator to show all records with a date that's
before the value in the date field on the right side.
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Less Than or Equal To (≤)
. Keys in the table on the left side of the dialog box have to
be less than or equal to the keys on the right side of the table. Use this operator to show
all records with a date that's before or on the value in the date field on the right side.
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Greater Than (>)
. Keys in the table on the left side of the dialog box have to be greater
than keys in the table on the right side. Use this operator to show all records with a date
that's after the value in the date field on the right side.
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Greater Than or Equal To (≥)
. Keys in the table on the left side of the dialog box must
be greater than or equal to the keys on the right side of the table. Use this operator to
show all records with a date that's after or on the value in the date field on the right side.
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Cartesian Join (x)
. All records in the table on the left are related to all records in the
table on the right, regardless of the value in their key fields. A Cartesian join is the only
one where it doesn't matter which fields you choose as keys. But if you like things nice
and neat, pick the primary key in each table. The Cartesian join is the least-commonly
used operator. One example: The
Go to Related Record
step doesn't switch to the target
layout if there are no records related to the record that's active when the step is run. That
could leave your script running in the wrong context. If you need to switch to another
context
and
it doesn't matter which records are active when you get there, you could use
a relationship with a Cartesian join. As long as there's at least one record in the target
table, the context will change.
As you go through the rest of this chapter, you'll see some of these operators in action. Now
it's time to learn another way to show just some of the related records in a portal.
Portal Filtering
Using a multiple criteria relationship as you did on
Multiple Criteria Relationships
is one
way to change what displays in a portal. But when you change the relationship's definition,
every portal, script, or calculation that uses the relationship will change, even if that's not
what you intend. And if you create a new TO every time you need a slight variation on a re-
