FRS keys enable you to map function and control keys (including arrow keys)directly to a program operation. While a function, control, or arrow key can always map to a menu item operation by position, you can map the key directly to the operation itself.

For instance, you might not want every operation to appear as a menu item, particularly if the operation is available across all the frames in an application. By requiring that certain repeated operations be invoked only through function or control or arrow keys, you can shorten long menu lines and use the menu primarily for operations that are unique to each frame.

Because not all keyboards have the same set of function keys, it makes little sense to assign an operation directly to a particular key inside an application. Instead, you equate operations with logical FRS keys. The FRS keys can then be mapped to function, control, or arrow keys at any of the four mapping levels.

FRS keys invoke operations only when specified in the application. A mapping file, by itself, merely assigns the FRS key to a function or control or arrow key; it cannot define the meaning of the FRS key. A FRS key must be equated with an operation when you write the application. For instructions on how to do this, see the Forms-based Application Development Tools User Guide. The Ingres forms-based tools also use FRS keys extensively. For more information, see Predefined FRS Keys.

You can define the same operation for both a menu item and a FRS key. The end user can then activate the operation either with the key that is mapped to the menu item's position or with the key that is mapped to the FRS key. This means the user is always be able to invoke the menu item with the same function key, even if the item's position on the menu line changes from frame to frame. Whenever an operation has been associated with both a menu item and an FRS key, the label for the menu item indicates the function or control or arrow key that maps to the corresponding FRS key, not the function or control or arrow key that maps to the item's position on the line.

For the end user to invoke an operation through an FRS key, two conditions must be met:

Mapping the FRS key to a function or control key is handled identically to mapping a menu item or FRS command. If an FRS key defined in an application is not mapped to a function or control or arrow key, the end user has no way of accessing that FRS key's operation, unless the operation itself has also been defined for a menu item.

An FRS key is designated by the keyword frskey, followed by an integer in the range 1 to 40.

For example, the following statement maps FRS key 7 to function key 2:

By pressing PF2 or F2, the user invokes the operation to which FRS key 7 has been defined, within the current frame.

The Ingres forms-based tools consistently equate certain FRS keys with standard menu item operations. Because of this, the end user can always use the same function or control or arrow key to perform that operation, no matter what its position on the menu line. Because the end user does not need to refer to the menu item's label, these operations are usually located at the end of the menu line, allowing those operations that are unique to a particular frame to appear first. For example, if frskey1 is mapped to control-H, the end user can always get help by pressing Ctrl+H.

FRS key operations are predefined in the applications code for the Ingres forms-based tools as shown in the following table. The terminal level key‑mapping files contain default key assignments for these FRS keys. For more information, see FRS Mapping File (Windows) and Terminal Type Level Mapping (for Linux).

An application developed with an embedded query language or 4GL cannot automatically have the same FRS key-menu item linkage. By using this table as a model for associating FRS keys with program operations, an application developer can help provide a consistent end-user interface for all custom applications that is also consistent with key usage in the Ingres forms-based tools.

Specifications written using the function key facility provided in earlier releases of Ingres continues to operate correctly. If desired, such specifications can be placed in a mapping file containing statements using the new function/control/arrow key mapping facility. In a future release, however, the function key facility is phased out; therefore, it is not documented here.