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This option sets the format in which rows are stored. The supported values are:

Value Description
expanded Rows are stored in the machine native format.
compact Rows are stored in the platform independent compressed format.
Compact Format

The compact format option ensures database portability between different hardware architectures (like X86 and PowerPC). If the system design enables hardware using different architectures communicating with each other, the compact setting must be used to correctly communicate database information to and from the TFS.

The compact option may save a few bytes of storage and communication packet size at the expense of possible performance degradation since all numbers will need to be decoded to use and encoded to store.
Expanded Format

The expanded format option stores all numbers in the machine native form of the hardware architecture. While this may provide a slight performance improvement in reading values because of the elimination of a decoding step, the expanded format causes the database image to be non-portable.

The expanded option should only be set if the database will never need portability and performance is affected using the compact setting.
Default Value

If the item_format option is not defined, the default value of compact is used.


Database Configuration Options

This option key is associated with the RDM_DB handle (or RDM_CPP::Db for C++) and can be set using one of the following functions:

The option key can also be associated with the RDM_TFS handle (or RDM_CPP::TFS for C++) which will be inherited by the next RDM_DB handle (or RDM_CPP::Db for C++) allocated. Modifications to the RDM_TFS after the RDM_DB is allocated have no effect on the allocated RDM_DB. The following functions can be used to set the key/values to be inherited later: