Editing filters

You can modify the properties of existing filters. There are two ways of modifying the conditions that select values from the data source: basic mode, where you select values from a set of lists, or advanced mode, where you enter filtering conditions using ObjectServer SQL syntax.

To edit a filter:

1. Open the Filter Builder.
2. Select the Category radio button and choose the category that contains the required filter from the list below Category.
3. Click the name of the filter in the list of matching filters.
4. Modify the general properties of the filter as required:

   Default View

   Select the view to associate with the filter. The default view is applied when you launch an AEL with the filter but do not specify a view. The default view is also applied when you launch an AEL from an Event Dashboard by clicking the monitor box that is associated with the filter.

   Collection

   For global filters and system filters only: select the filter collection or collections to which you want to add the filter.

   Description

   Type a description that helps identify the purpose of the filter.

   Data Source

   Select the data source or data sources that contain the fields against which you want to run queries. Click Show Data Sources to display a list of available data sources.

   Important: Each filter requires at least one data source, that is, an ObjectServer, from which the Filter Builder obtains the fields for the SQL query. If you select multiple data sources, the Filter Builder displays only the fields that are common to all those data sources. The data sources that are selected in the Filter Builder are not used in the event lists, Map Editor, or Event Dashboard to retrieve event data. You select the data sources for event data retrieval in the portlet preferences for those portlets.

   If you want to add a data source to an existing filter, make sure that the alerts.status table of the new data source contains all the fields that the filter specifies. If you add a data source that does not contain all the specified fields, the filter might return erroneous results.

   The default data source corresponds to the default ObjectServer specified in the ncwDataSourceDefinitions.xml configuration file.

5. Modify the conditions that select values from the data source as required.

   Table 1. Defining selection criteria for a filter

   Mode	What to do
   Basic	Click the Basic tab and, in the first row, create a filter condition as follows: From the Field list, select a field from the specified data source. From the Comparator list, select a comparator. In the Value field, type a numeric data type value, or a string data type value. The data types must correspond to those in the ObjectServer field. String data type entries in the Value field must be contained in single quotes. Use the LIKE and NOT LIKE comparators for regular expression pattern-matching metacharacters against the entry in the Value field. To add additional filter conditions, click New Condition. You can add as many filter conditions as required. To remove a filter condition, click Remove Condition next to the appropriate condition. Use the radio buttons to specify how the filter conditions combine in aggregate: Select All to trigger the filter only if all the conditions are met. Select Any to trigger the filter if any of the conditions are met. See Sample SQL statements for sample SQL statements that are generated based on the radio button selected. To preview the actual SQL WHERE clause output, click Advanced.
   Advanced	Click Advanced. In the SQL Where clause text field, enter any valid ObjectServer SQL WHERE clause. For brevity, the SELECT part of the statement is omitted and you supply the WHERE clause only; the view associated with the filter determines the columns in the alerts.status table that are selected.

6. To modify the metric for the filter, click Metric and modify the following fields as required:

   Label

   Type a title for the metric.

   Function

   Select a function to perform on the field data. The following functions are available:

   • Average: Calculates the average value of the selected field for all records that match the filter.
   • Count: Calculates the total number the records that match the filter. The selected field is not used for this calculation.
   • Sum: Calculates the total of the selected field for all records that match the filter.
   • Minimum: Returns the lowest value of the selected field in records that match the filter.
   • Maximum: Returns the highest value of the selected field in records that match the filter.

   Field

   Select a field from the list that the function is to act on. The list contains all available fields in the alerts.status table of the data source.

7. Click Save to save the filter and continue working in the Filter Builder, or click Save and Close to save the filter and close the Filter Builder.