Project PDA

Databases are typically imported into handheld devices when a user performs a HotSync ® operation that installs an application. When a database is imported into a Palm Powered handheld, the Palm OS converts the database into standard Memory Manager objects. The Memory Manager tracks the size of each record or resource, and thus adds memory overhead; this means that the size of a database on the device is larger than its size on the desktop computer.

Currently, there are three types of file formats that are commonly used in the Palm OS platform:

• Palm™ database (PDB)
• Palm query application (PQA)
• Palm resource (PRC)

Files with a pdb or pqa extension are record databases. Files with a prc extension are resource databases. Please note, however, that the filename and extension on the desktop do not determine the name or type of database created on the handheld. The database header information inside the file determines a database name and type.

Palm Database (PDB) Files

A PDB is a record database generally used to store data for an application.

Palm Resource (PRC) Files

A Palm resource file contains a different type of data (resources instead of records), but has an almost identical structure to a PDB file. Palm OS applications are resource databases. A Palm OS application contains code resources as well as user interface resource elements.

Palm Web Clipping Application (PQA) Files

A PQA is a PDB that contains world-wide web content. On the Palm device all PQAs are associated through the Launcher with the Web Clipping Application Viewer (Viewer) software. When a user opens a PQA file for viewing, the Applications Launcher starts the Viewer, which in turn displays the contents of the selected PQA.

Resource databases contain resources, not records; however, in some places the documentation and structure types use the term record generically to refer to the individual data entities stored inside of databases, including resource databases.

See also PDB File or Palm Database File.