User manual

Table Of Contents
About relationships | 137
Each table occurrence in the relationships graph represents a separate view into
your data. When you join two tables, you are leveraging the two existing views
to create a third view. As you add tables to your relationships, each successive
table represents an additional set of criteria that must be met before related data
can be accessed in that relationship.
You can create a relationship between any two tables in the relationships graph,
but the relationship must not create a cycle, or closed loop between tables. That
is, each series of relationships must have a starting table and an ending table,
and those tables must be different tables.
Because each relationship represents an additional set of criteria, you must be
aware of your context within the relationships graph. Context is the point in the
graph from which a relationship is evaluated. Because the graph is never a
cycle, each point along the graph offers a different perspective into your data.
Because FileMaker Pro does not permit you to create cycles within the
relationships graph, any attempt to create a cycle causes FileMaker
Pro to
generate a new, uniquely named table occurrence. A new occurrence functions
like any other occurrence in the graph and allows you to continue with your
new relationship.
For more information about the relationships graph, see Help.
About match fields for relationships
When you create a relationship between tables, you choose one or more fields
in each table as match fields. Match fields usually have common values. In a
typical relationship, a record in one table will be related to records in another
table that share a common match field value.
For example, a Customers table and an Invoices table can each use the field
Client ID to uniquely identify each customer and purchase. If the two tables are
related using Client ID as the match field, a record in the Customers table can
display a portal showing each invoice with a matching Client ID, and in the
Invoices table, each invoice with the same Client ID can display consistent
customer data.
The match fields used in a relationship can have different names. Match fields
can be any field type except container or summary.
φμπ10_υσερσ_γυιδε.βοοκ Παγε 137 Μονδαψ, Αυγυστ 25, 2008 3:59 ΠΜ