The Name or description term type can filter for feature name or description of features. The definition of the term includes the selection for name or description a comparison operator and a comparison string.
Setting |
Description |
Filter for |
Specifies if the filter uses feature names or descriptions |
Comparison operator |
The comparison operator used, see Table 2 for details |
Comparison string |
The comparison string can be up to 4000 characters. |
Table 1: Settings for this view filter term type
All comparisons are done case insensitive i.e. Feature1 is considered the same as feature1. If the term filters for feature name the comparison string must not be empty, when searching for description the comparison string can be empty to search for 'undescribed' features. The comparison string can have a maximum length of 200 characters when filtering for name and a maximum length of 4000 when filtering for description: Table 1 shows the supported string comparison operators, table 2 shows the wildcard characters allowed with the like comparison operator.
Operator |
Description |
Equal |
Tests for an exact but case insensitive match with the given comparison string. Wildcard characters are not supported, therefore user can search for special characters like %,[], ^, _. |
Contains |
Filters for all strings that contain the given comparison string.Comparison is done case insensitive. Wildcard characters are not supported, therefore user can search for special characters like %,[], ^, _. |
Start with |
Filters for all strings that start with the given comparison string. Comparison is done case insensitive. Wildcard characters are not supported, therefore user can search for special characters like %,[], ^, _. |
Ends with |
Filters for all strings that end with the given comparison string. Comparison is done case insensitive. Wildcard characters are not supported, therefore user can search for special characters like %,[], ^, _. |
Pattern |
Filters for all strings that contain the given comparison pattern. Comparison is done case insensitive. Wildcard characters are supported in the comparison pattern. |
Table 2: Supported string comparison operators
Wildcard character |
Description |
Example |
|---|---|---|
% |
Any string of zero or more characters. |
%Name% matches AB Name as well as AB Name CD as well as Name1 %Name% does not math AB Nam CD %Name does not math Name CD |
_ |
Any single character. |
Feature _ matches Feature 1 as well as feature A |
[] |
Any single character within the specified range ([a-f]) or set ([abcdef]). |
Feature [12345] matches Feature 1, Feature 3 but not Feature 9 |
[^] |
Any single character not within the specified range ([^a-f]) or set ([^abcdef]). |
Feature [^A-M] matches Feature M to Feature Z but not Feature A to Feature M |
Table 3: Wildcard characters that can be used with the like operator
Under certain circumstance string comparison can be time consuming and for huge amounts of data. Performance is of course always depending on your system environment the amount of data you have in your system and your overall system load.
When querying huge amounts of features following hints might help to specify optimal filters:
•Using the like operator with a comparison string that includes wildcard characters needs a full scan of all features and is therefore O(n) being the total number of stored features.
•The Contains and Ends with operators need to scan all features and are therefore O(n) with n being the total number of stored features.
•If you search for feature name the Equal and starts with operators use an indexed query and are therefore O(log n) with n being the total number of stored features.
The system stores the execution time of each view when it evaluates the view members, see view member caching for details.
