Once again I feel the need for a recap. You know that FileMaker fields have a dialog box for setting options such as auto enter, validation and storage. Auto enter allows you to create a set of conditions in which a field is automatically populated with data you selected. Validation is where a field can be verified that it contains the data or type of data you want within it. The storage options area is a flexible way to control how data is stored.
The repeating field is one of those “unique and flexible” storage types. In fact, it is so unique, you probably won’t find anything like it in most other database systems.
A repeating field can be used with any type such as text, number and date. The only exception to this the summary field type. The storage option of repeating fields allows you to have multiple cells of information within the same field. Once again, as far as I know, FileMaker is the only database application that has anything like repeating fields.
To make a field a repeating field, you select the field, click the options buttons, click the storage tab and in the storage options area, you define how many repetitions you want the field to have. There is one additional step you need to take when you put a repeating field on a layout. You have to tell FileMaker how many of the repetitions you want to show on the layout. This is done in layout mode ( of course ), you click on the field and choose the field options selection from under the Format menu.
Repeating fields were popular before FileMaker went relational and portals replaced repeating fields in most FileMaker solutions. Portals have significant advantages over repeating fields. Portal data is easy to search upon, report upon and write scripting events with. So you might wonder why repeating fields are still around.
As you might know, databases can become complex. There are databases that were built with repeating fields and those databases rely on them. Forcing every database owner to rewrite repeating field logic to portal logic would be a tough decision. Also, the act of converting this data isn't always easy to do.
Another good reason is those crazy FileMaker developers started using them for all sorts of things they were not designed to do ... and ... some of those things they did turned out to be downright useful. Repeating fields can be used to hold graphics, sounds, movies and even buttons in a dock like appearance.
PLEASE NOTE: If you are up on your relational design theory, you might remember about a little thing called the rules of normalization? For a database to comply with first normal form standards, it must only contain one value. As you can see, repeating fields are a slap in the face of the first normal form rule.
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© 2007 - Dwayne Wright - dwaynewright.com
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