All data of an infotype is stored on the database with its period of validity.

When you change one or more fields of an infotype record, the system creates a new record with a new validity period. The date on which you changed the record is the start date of this new record.

Therefore, the data fields that are not affected by the changes contain the same data over several infotype records and validity periods.

From a logical perspective, these fields are valid in all infotype records until they are changed.

When seen from this logical perspective, each field of an infotype has its own validity period.

This is illustrated in the following case:

An employee has worked as a programmer for three years in three different personnel areas.

The following organizational assignment data is available:

If you only require the time period during which an employee performs a specific job and not his or her personnel area for an evaluation, the following applies:

The physical view has three infotype records, the logical view one.

To create meaningful evaluations and avoid redundancies, create logical views for infotype records.

Select the infotype fields that are important for the evaluation and disregard the others.

In the above example, the data in the other fields is invalid for the evaluation since it is unknown which personnel area the employee belonged to from 1996 - 1998.

This view of the validity period of a group of infotype fields is known as projection.

The program code for the projection is: