Apple Network Setup manual Database Structure Example

C H A P T E R 1

About Network Setup

one active set entity. The entities referenced by the active set entity comprise the active network preferences. All set entities have the same type.

■icon. An entity can include a reference to a custom icon. The custom icon is not currently used, but may be used by future system software to display a visual representation of the entity.

Within each entity there are zero or more preferences, distinguished by a preference type (an OSType). A preference is the atomic unit of data in the database. When you read or write data, you do so one preference at a time. Typically the data for a preference is protocol-dependent. Its format is determined by the entity class and type and by the preference type itself. To read or write a preference meaningfully, you must know the format of the preference data. The reference section of this document describes the format of every preference used by the Apple protocol stacks. In most cases, this description includes a C structure that mirrors the structure of the preference itself.

Note

For most preferences, the data format is the same as for the equivalent resource in the legacy preference files. If you are familiar with the legacy file format, you should be able to easily understand the preference data format. See “Legacy Issues” (page 21) for more information on how Network Setup synchronizes the database with the legacy preferences files.

Database Structure Example

Figure 1-5 shows an example of how the Network Setup database might be structured on a particular computer.

Network Setup Database Fundamentals 17