Normally you define a flexfield only once in your form, usually at the form startup event. However, sometimes you need to change this definition later. For example, you may want to make the flexfield non-updatable and non-insertable. Instead of redefining the entire flexfield with UPDATEABLE=>'' and INSERTABLE=>'' and all the other arguments the same as before, you can use the following update procedures to change only the arguments that need to be modified.
You can use the update procedures to control any of the "other optional arguments" that you specify in your flexfield definition procedures. You cannot use these procedures to change arguments such as which fields your flexfield uses, since those arguments essentially identify the flexfield rather than modify it. For example, you may specify new values for the VALIDATE argument, but you may not specify new values for the DESCRIPTION or DATA_FIELD arguments.
Once a flexfield has been defined in your form, whenever the FND_FLEX.EVENT calls occur at various block or form level triggers, these events apply to all flexfields defined in the block or form. This makes it difficult to handle situations where you want to make FND_FLEX.EVENT calls for some flexfields but not others. For example, you may not want to call VALID for a particular key flexfield in PRE-UPDATE, but want to call it for all other flexfields in the block. Using the update procedures you can enable and disable a flexfield definition so that the FND_FLEX.EVENT calls do not apply to disabled flexfield definitions.
The update procedures provide a special argument, ENABLED, in addition to the optional arguments you can specify. You specify N for this argument to disable the flexfield, and you specify Y to enable the flexfield. You cannot use ENABLED in your normal flexfield definition procedure calls (which automatically enable the flexfield).