Policy Filter Rules
A Snapshot Policy Filter Rule contains the logic which determines if a database record should be processed by the snapshot policy. There are several types of policy filters built into CopyStorm Snapshot.
- All Changes — this filter always indicates that a record should be processed. Use it when all changes to records should be snapshot.
- Column Expression — with this filter a rich expression based on columns in a record can be used to determine if a record should be snapshot.
- Deleted Records — this filter only matches records that have been deleted in Salesforce. This filter is used to build recycle bin type policies.
- SQL Predicate — this advanced filter supports injecting user specific SQL fragments into a query that determines if a record should be snapshot.
The Filter Rule for a Snapshot Policy is specified on the Main Tab of the snapshot editor.
Parameters specific to the selected Filter Rule Type can be set on the Filter Rule Parameters tab.
![Parameter Summary](https://learn.capstorm.com/wp-content/uploads/sites/2/2022/03/Parameter-Summary.png)
Nearly all Filter Rule Types support the concept of a White and/or Black list for selecting the tables to be processed by the policy.
- A White List indicates tables to include in the snapshot.
- A Black List indicates tables to exclude from the snapshot. All tables not on the black list will be included.
Typically the technique used for selecting tables for a snapshot is either by White List or Black List. However, if you are brave (and using regular expressions) both a White and Black list may be useful.
The following example (from the All Changes filter rule type) illustrate the components of the White/Black list editor.
- The pull-down menu indicates whether tables should be selected by White list, Black list, or both.
![WhiteBlackList](https://learn.capstorm.com/wp-content/uploads/sites/2/2022/03/WhiteBlackList.png)
The dialog for selecting tables is nearly the same for a White or Black list. The following example is for a White list.
![Select Tables](https://learn.capstorm.com/wp-content/uploads/sites/2/2022/03/Select-Tables.png)