SMC Networks 8606SX - annexe 2 User Manual page 70

C D
OLLECTING ATA WITH
Syntax for Complex Expressions
A complex expression combines several simple expressions using logical operators. Each expression
must be enclosed in parentheses. The syntax for a complex expression follows:
(Simple Expression) Logical_Operator (Simple Expression)
As described in the previous section a simple expressions should have three basic elements, namely,
a Variable, Relation and Value. Legal values for each element are described under the syntax for
simple expressions.
Logical_Operator - Legal values include:
AND -- Both expressions must be true to meet a given condition
OR -- One true expression is enough to meet a given condition
Elements of Filter Formulas
Parameters
Variable
Relation
Value
Logical_Operator
Notes: 1. The equal to (
2. If more than one expression is used to define a filter, first enclose each expression in
parentheses and then combine them with
the order of evaluation. Otherwise conditions are evaluated from left to right.
3. If you want to test a log process without saving data into the database, set the filter
formula to an impossible condition; for example, (TIME<000000).
Example: Filter Formulas
Some possible filter formulas include:
•
•
•
•
7-8
L M
OG ANAGER
Example
VALUE Value of the data
Date when the value is reached
Time when the value is reached
> Greater than
< Less than
>= Greater than or equal to
<= Less than or equal to
== Equal
!= Not equal
256 Positive number (4 byte unsigned integer)
19990229 Date format (YYYYMMDD) for 2 Feb 1999
135501 Time format (HHMMSS) for 01:55:01pm
AND Both statements must be true
OR Either statement may be true
) and unequal (
Description
) expressions follow C language syntax.
or . Parentheses are used to maintain