| Description | Information about a single expression. New expressions
can be created using expNameStatus.
To create an expression first create the named entry in this
table. Then use expExpressionIndex to populate
expExpressionTable and expObjectTable. For expression
evaluation to succeed all related entries in expNameTable,
expExpressionTable, and expObjectTable must be 'active'. If
these conditions are not met the corresponding values in
expValue simply are not instantiated.
Deleting an entry deletes all related entries in
expExpressionTable and expObjectTable.
Because of the relationships among the multiple tables
for an expression (expNameTable, expExpressionTable,
expObjectTable, and expValueTable) and the SNMP rules
for independence in setting object values, it is
necessary to do final error checking when an expression
is evaluated, that is, when one of its instances in
expValueTable is read. Earlier checking need not be
done and an implementation may not impose any ordering
on the creation of objects related to an expression other
than to require values for expName and expExpressionIndex
before any other related objects can be created.
To maintain security of MIB information, when creating a new
row in this table, the managed system must record the
security credentials of the requester. If the subsequent
expression includes objects with expObjectSampleType
'deltaValue' the evaluation of that expression takes place
under the security credentials of the creator of its
expNameEntry. |