User manual

98 FileMaker Pro User’s Guide
About the relationships graph
When you work with tables in the relationships graph, you organize your view of your data. Tables shown
in the relationships graph can be located in the current FileMaker
Pro file, in an external FileMaker Pro file,
or in an external ODBC data source.
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.
Relationships graph In the Relationships tab of the Manage Database dialog box, you can see the occurrences of tables both
in the current file and from any external, related database files. In this relationships graph, you join tables
and change relationships between fields in different tables.
When you create a new table, a visual representation, or occurrence, of the table appears in the
relationships graph. You can specify multiple occurrences (with unique names) of the same table in order
to work with complex relationships in the graph.
Source file The file from which you add a table to the relationships graph.
Source table The table upon which one or more tables in the relationships graph are based. The source table is the table
defined in the Tables tab of the Manage Database dialog box.
Term Description