Formula functions treat attributes as numeric, text or
timestamp. Attributes also have other characteristics that further
categorize them and inform your choice of formula function or query-based
view..
- Numeric
- Numeric attributes can
represent a percentage, seconds, bytes or some other unit of measurement.
When
entering a hexadecimal value in a cell, prefix the number with zero
and the letter “x”, as in 0x123ab for hex value 123ab. In z/OS applications,
for example, DASD volume serial numbers are hexadecimal.
- Text
- Single quotes are
required around multiple-word text values. The timestamp and, usually,
enumerated attributes are treated as text attributes.
- Words with apostrophes, such as that's or agent's,
cannot be used. Instead, consider using a wildcard or, if appropriate,
use Return a subset of the
string or or Scan for string within a string and
specify the letters preceding the apostrophe.
- You can use an * asterisk wildcard to begin or end the attribute
value in a Value
of expression (Equal operator only), Check for Missing Items, Scan for string within a string, or Return a subset of the string function.
- You can also use the ? question mark wildcard for a single character
at that position. When using the ? question mark wildcard
with the Value of expression function, append
the text with an * asterisk. For example, enter Sa?e* to find Safe
and Sale.
- Timestamp
- The Timestamp attribute is
treated like a text attribute formatted as mm/dd/yy hh:mm:ss. Some
timestamp attributes have different names, such as Start Date &
Time and Recording Time.
Some timestamp functions enable
you to add and subtract values from the second attribute by using
the + and - symbols. The value can be one or two digits followed by
D for Day, H for Hour, M for Minute, or S for Second.
- Enumerated
- Enumerated attributes have a predefined set of
values and the tabular editor supplies a list to choose from. These values are usually treated as
text.
Some enumerated values are actually numeric, with text representing
some or all of the numbers, and you can type the numeric value instead
of choosing a text equivalent from a list. For example, the WebSphere
MQ attribute, Action to Take has values of n/a, delete, create,
and discover. But you can also enter 5 or 6, which represent
other actions. See the help topic of the attribute in question for
a list of possible entries.
- Single-row or multiple-row
- Depending on the type of attribute group, data samplings return
either a single row of data or multiple rows. For example, the Windows
Memory attribute group returns one row of a data for a managed system,
whereas the Windows Process attribute group returns multiple rows,
one for each process running.
A single-row attribute group will
return multiple rows if it has been configured for historical data
collection.
Attributes from different attribute groups can
be combined in the same situation if they are from single-row attribute
groups. Local Time and Universal Time are the exception—they can be
combined with any group.
When you create a query for an attribute
group that returns multiple rows, consider adding a formula as a pre-filter
to limit the rows returned to those of interest, which also reduces
network traffic overhead.
- Pure or sampled
- Attributes behave differently in situations depending on whether
they are able to be sampled at intervals. Attributes that cannot be
sampled are those that have no value until something happens, such
as those for the Windows OS File Change attribute group. These unsolicited
notifications are called pure events Examples of pure events
are an out-of-paper condition on a printer and an occurrence that
adds an entry to the Windows System Log.
Events from sampled situations
are closed automatically when the situation is no longer true (goes
back to false). Because of the nature of pure events, they are not
closed automatically like sampled events but must be closed manually
unless an Until clause is included in the situation definition.