Populating properties by using the Column Populator tool
After adding a new column to a table schema, you can populate values for that new column by using the Database Column Populator or the service-enabled Column Populator command-line tools.
You can expose a
Single Value
property contained in the Storage Stream (BLOB) by adding a new column to the table. Columns can be added by using the Property Optimization tool or the Modify Schema wizard. New columns will contain values only for rows added or updated after that column was added. Use the Column Populator or the service-enabled Column Populator to copy the value for each existing row from the Storage Stream into the new column.
A single database table may contain rows from two or more concrete classes. The value in the pxObjClass database column identifies the row's class. When you run the Column Populator tool, you specify the classes to be populated. Rows on the database corresponding to instances of classes that are not specified as included are unaffected by this utility.
The column populator tool does the following actions:
- Assembles a list of concrete classes to be processed.
- Determines which database tables contain the rows that correspond to instances of these classes.
- Performs an SQL Select statement immediately followed by an SQL Update statement for each row corresponding to those classes.
You can also use the Column Populator tool to rebuild database indexes, and to rebuild Index- instances defined by Declare Index rules that are related to the database table.
- Populating properties by submitting a request to an active instance
You can use the prpcServiceUtils tool to extract a property value from the Storage Stream or pzPvStream (BLOB) column into a newly added table column, using a web service to connect to an active instance of Pega Platform. This tool can also rebuild Index- instances that are defined by Declare Index rules.
- Populating properties by using a direct connection to the database
You can use the prpcServiceUtils tool to extract a property value from the Storage Stream or pzPvStream (BLOB) column into a newly added table column, by using a web service to connect to an active instance of Pega Platform. As a best practice, use the Database Column Populator when Pega Platform is not running.
- Example column populator configurations
The system uses pattern inheritance, defined by segments of the class name ending in a hyphen, to map classes to tables when no more specific Database Table instance is defined. For example, if (through a Database Table instance) class MyCo-Finance-Loans maps to a table named Loans, then classes such as MyCo-Finance-Loans-Defaulted are also mapped to Loans.
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