How To Database Updates in Pega 8 & Configuration

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In this quick tutorial you will learn How To Database Updates in Pega 8.

Most Pega applications need to exchange data with each other as well as with external systems.

It contains all of the rules and system information for a Pega application.
Designers can create and update rules and system settings without updating the database structure.
Detailed knowledge about the database is unnecessary for most application tasks.

Pega application information such as cases, assignments, and case history is stored in PegaDATA.
As users interact with a Pega system, rows of the database are automatically created, updated, saved, and deleted.
Pega separates this data into a separate database from rules and system data to support high availability and in-place upgrades.

Pega applications almost always require access to data stored outside of the application.
To directly manage the data read from and written to an external database, you can create an external class in your application.

An external class cannot belong to a class group.
It corresponds to a database table not administered by Pega.
Each external class should be mapped to a unique database table.
An external class does not contain either the pzInsKey or pxObjClass properties.
These properties are used by Pega as key columns to identify rows in tables in the PegaRULES and PegaDATA databases.
The external class uses the key column specified by the database table to identify unique rows instead.
An external class maps Pega properties to database columns.

As a best practices pega suggest the use of data pages to both read and save data back to the system of record for easy configuration and maintainability.
By configuring a savable data page, you can read and write updated information without the use of an activity.

When advanced processing to a database table cannot be achieved with savable data pages.
You can read from, and write to the database with Obj-methods using activities.
Obj-methods are a subset of activity methods used to operate on one or more objects, or rows, in a database table.

Obj-Open or Obj-Open-By-Handle loads an instance of a class stored in either the PegaRULES database or an External database.
Both methods create a clipboard page for the open instance.
Obj-Browse searches the database, retrieves multiple records, and copies them to the clipboard as an array of embedded pages.
Obj-Refresh-and-Lock tests whether a clipboard page is current and if a lock is held.
If the object is not locked, the activity acquires a lock and refreshes the page if it is stale.

Obj-Save saves the contents of a clipboard page to the database.
- It immediately writes the object to the database only if the WriteNow parameter is selected.
- If the WriteNow parameter is not selected, the Obj-Save operation becomes a deferred save.
- A deferred save adds a deferred operation to an internal list of operations to be performed on the next commit.
A valid reason to perform a WriteNow is the need to immediately reread the instance before issuing a commit.

Use Obj-Delete or Obj-Delete-By-Handle to remove an instance from the database.
- Obj-Delete to delete a database row identified by a page on the clipboard.
- Obj-Delete-By-Handle to delete an instance using its unique ID without requiring a page on the clipboard.

Obj-Save-Cancel: cancels the most recent uncommitted Obj-Save method so that the instance is not written as part of a later Commit operation.
Rollback method: cancels or withdraws any previous uncommitted changes to the PegaRULES database (and to external databases accessed from an external class) from the current thread.

The Connect SQL rule provides four tabs to enter SQL statements that execute during performance – Open, Delete, Save, Browse.
Use a Connect SQL rule To execute a SQL command or stored procedure
Invoke Connect SQL rules from an activity using RDB methods.