User manual

72 FileMaker Pro User’s Guide
About the relationships graph
When you work with tables in the relationships graph, you are using
them to organize your view into your data. 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.
Since 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.
This 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.
For more information about match fields, see Help.
Types of relationships
When you join two tables using a relationship, you establish criteria
that FileMaker Pro uses to display or access related records.
Your criteria can be simple, such as matching a field in Table A with
a field in Table B, or more complex. A more complex relationship
definition will usually return a narrower set of related records.
Examples of complex relationships include using multiple match
fields on one or both sides of the relationship, comparing match fields
using non-equal relational operators, or using calculated match fields.
Single-criteria relationships
In a single-criteria relationship, data in one field is matched to data in
another field.
For example, a record in either table is related to any record in the
other table when the values in the Client ID field in the Clients table
and the Client ID field in the Phone Numbers table are the same.
Match field Match field