What is use of Shortcuts in informatica?

If we copy source definaltions or target definations or mapplets from Shared folder to any other folders that will become a shortcut.

Let’s assume  we have imported some source and target definitions in a shared folder after that we are using those sources and target definitions in another folders as a shortcut in some  mappings.

If any modifications occur  in the backend (Database) structure like adding new columns or drop existing columns either in source or target I f we reimport into shared folder those new changes automatically  it would reflect in all folder/mappings wherever we used those sources  or target definitions.

Target Update Override

If we don’t have primary key on target table using Target Update Override option we can perform updates. By default, the Integration Service updates target tables based on key values. However, you can override the default UPDATE statement for each target in a mapping. You might want to update the target based on non-key columns.

Overriding the WHERE Clause

You can override the WHERE clause to include non-key columns. For example, you might want to update records for employees named Mike Smith only. To do this, you edit the WHERE clause as follows:

UPDATE T_SALES SET DATE_SHIPPED =:TU.DATE_SHIPPED,

TOTAL_SALES = :TU.TOTAL_SALES WHERE EMP_NAME = :TU.EMP_NAME and 

EMP_NAME = 'MIKE SMITH'

If you modify the UPDATE portion of the statement, be sure to use :TU to specify ports.