User manual

8-2 FileMaker Pro User’s Guide
Relational database terminology
Before you begin, you should understand the following terms for
relational databases and lookups. These terms are illustrated in the
sections that follow.
About relational databases
A relational database is one or more discrete database files (or
database tables) that, when used together, contain all the data you
need for your work. In relational databases, each occurrence of data
is stored in only one file at a time, but you can access and work with
that data from any file. Because data from a related file is only
displayed in—and not copied into—the master file, you always see
the data in its current state.
Working with related data promotes consistent data entry and
retrieval, and reduces the existence of duplicate data among the
database files.
This term Means
Master file For relational databases, the file that accesses and displays
data from another file.
For lookups, the file that contains the copied data. It’s the file
the lookup originates from and the file the data is copied to.
Related file For relational databases, the file that contains the data you
want to access and work with in the master file.
For lookups, the file that contains the data to copy. It’s the
file the lookup goes to and the file the data is copied from.
A related file and the master file can be the same file. (This
is called a self-join.)
Match field A field in the master file and a field in the related file that
each contains values used to access matching records. (A
match field is sometimes called a key field or primary key.)
For each relationship, you select one match field in each file.
For relational databases, values in match fields must match
each other in some way for a relationship to be established
between the two files. (See “About match fields for
relationships” on page 8-5.)
For lookups, values in match fields don’t have to be equal to
each other. For example, you can set an option to copy the
next lower value when the match fields aren’t equal. (See
“Defining lookups between files” on page 8-13.)
Relationship An expression you define that contains requirements which,
when met, establish a relationship between values in the
match fields. (A relationship is sometimes called a link or a
join expression.)
You define a relationship in the file you want data displayed
in, not the file you want data displayed from.
Related record A record in the related file whose match field contains a
value that matches the value in the match field of the master
file, according to the requirements of the relationship.
Related field A field in the related file that contains data you want to
access and work with in the master file. After a relationship
has been established between data in the match fields, the
data in related fields can be used in the master file.
You place related fields on a layout of the master file, either
by themselves or in a portal. You can then work with data
that’s in related fields in all modes.
In the master file, a related field name appears as
Relationship name::Related field name or as
::Related field name
Portal An object on a layout of the master file in which you can
place related fields. Use portals only when you want to work
with data from more than one related record for each record
in the master file.
Portals display data from related fields in rows, one record in
each row.
Lookup source
field (for lookups
only)
A field in the related file that contains the data you want to
copy. It’s the field the data is copied from.
Lookup
destination field
(for lookups only)
A field in the master file that you want to contain the copied
data. It’s the field the data is copied to.
This term Means