Time-Dependency of Master Data 
Use
You can maintain master data for cost centers , cost elements , activity types and business processes with time-based dependencies. You can make changes at any time for any time interval. The saving of data is also time-dependent. This can result in multiple database records for a master data record, with different information stored in each database record.
Features
SAP has determined the times when a field may be changed - these cannot be changed. The following time-dependencies are possible:
Not time-based
The corresponding fields are only valid for the whole period of time in which the object exists, and can only be changed during this period.
Example: Hierarchy area
Day-based time dependency
You can change the corresponding fields as often as you wish, and they are also valid for one ore more days.
Example : Lock indicator
Period-based time dependency
The corresponding fields are valid for one period (for example, a month) and are not changeable during this time.
Example: Profit centers
Fiscal-year-based time dependency
The corresponding fields are valid for a whole fiscal year and cannot be changed during that year.
Example : Cost center currency
For fields that are time-dependent on a daily basis , you can set an indicator to specify whether they are to be saved on a time basis (and so become historically relevant ) in customizing for the given master data. See, for example, Specifying Time-Dependent Fields for Cost Centers .
Fields with period-based and fiscal year-based time dependencies are always historically relevant.
Caution
Note that time-dependent storage can lead to large volumes of data. Therefore, define only important fields as historically relevant.
( )
If the contents of all fields marked as historically relevant are identical in consecutive analysis periods, the SAP System replaces the multiple data records during master data maintenance with a data record for all the single record periods.
Activities
If you change master data marked as historically relevant, and define a new analysis period for the changed fields, the SAP System creates new data records and shortens the validity period of existing records.
Example
You create an object (such as a cost center) valid from 01.01.1996 to 31.12.1999, with the manager Brown. You then change the object by defining a different cost center manager for the period from 01.01.1997 to 31.12.1997. You marked the Manager field as historically relevant during Customizing.
The SAP System saves three data records. To display these in master data maintenance, select the Person responsible field and choose Drilldown :
One data record for the interval from 01.01.1996 to 31.12.1996, Manager: Brown
One data record for the interval from 01.01.1997 to 31.12.1997, Manager: Smith
One data record for the interval from 01.01.1998 to 31.12.1999, Manager: Brown
If you change master data fields marked as historically relevant without defining a new analysis period, the system changes the existing data record for the entire analysis period selected. You can find these changes listed in the change document.
Example
You proceed as with the previous example, but change the Person responsible field without defining a new analysis period. The SAP System creates only one data record for the Person responsible field from 01.01.1996 to 31.12.1999, Manager: Smith .
To change historically-relevant fields in multiple analysis periods, select the appropriate analysis periods during master data maintenance.
If you change master data fields that are time-dependent on a daily basis, and not marked as historically relevant, the SAP System changes the existing data record for the entire analysis period selected. You cannot define a new analysis period. You can find these changes listed in the change document.
Example
You have set the indicator for Person responsible to not historically relevant. Proceed in the same way as the previous example. The SAP System creates only one data record for the Person responsible field from 01.01.1996 to 31.12.1999, Manager: Smith .
The change document lists the master data field changes. To display the individual changes, choose
Environment
Change documents
For field/For cost center
in the master data maintenance, for detailed information on each change. Double click to call up the detail information for each change.
If you change master data fields that are not time-dependent, the SAP System changes the existing data record for the entire period in which the master data exists. When you change these fields, no new analysis period may be entered.
Time-based master data storage reduces the maintenance requirements in the SAP System. You can create master data across fiscal year boundaries, and use this data for more than one year without having to recreate the data again each year. You can make changes relevant to a given time-period at any time, without immediately affecting the current data.
Example
You have created a cost center with the following data:
Cost center 4110
Validity period: 01.01.1996 to 31.12.2000
This entry has the advantage that the cost center can be processed in the SAP System until 31.12.2000 inclusively.
On the other hand, you have created a cost center with the following data:
Cost center 4110
Validity period: 01.01.1996 to 31.12.1996
This has the disadvantage that cost center 4110 must be created again if you require it for the following fiscal year.
This rule applies to other objects in Cost Center Accounting, such as cost elements, activity types and business processes.
( )
In the example above, the analysis periods correspond to year boundaries according to the calendar year. You can, however, define periods not based on the calendar year.
This is especially necessary when you have used the fiscal year variant in Financial Accounting to define a postponed fiscal year, an over-long fiscal year or a shortened fiscal year. In these cases, the master data is not based on the fiscal year variants.