Understanding infotype Time constraint

•  Infotypes are information units in the Human Resources Management system. Groups of related data fields are bundled into infotypes.
• Infotypes structure information, facilitate data entry and allow data to be saved for specific periods. Infotypes serve as templates for users to enter data. From a database point of view, infotypes provide a data structure and a set of coherent data records. 
•  The infotypes Actions 0000,  Organizational Assignment 0001, Personal Data 0002, and Payroll Status 0003 are prerequisites for entering a personnel or applicant number.
•  Save the infotypes at intervals to build up an infotype history. The system stores a validity period for each infotype record. Therefore, several data records usually exist for each infotype of an employee, and each record has a different validity period.
•  You use a time constraint to determine how the data records of an infotype react to each other in terms of time.
• Several infotypes have subtypes, which break down information further. For example, technically speaking, the address types for infotype Address 0006 represent the subtypes
• Each infotype and subtype has a time constraint.
•  Time constraint 1: Complete saving with no overlaps at any time, that is, one valid data record of the relevant infotype must exist during the duration of the employee's employment at the company.
•  Time constraint 2: Incomplete saving without overlaps at any time, that is, of an infotype may exist at a given time. No more than one valid data record of the infotype can exist at any given time.
• Time constraint 3: Incompleteness and overlaps permitted, that is, any number of valid data records of an infotype may exist at any given time.

Time Constraints A: Only one record may ever exist for this infotype. It is valid from 01/01/1800 to 12/31/9999. Splitting is not permissible. View V_T582B Infotypes which are Created Automatically controls whether the system automatically creates the infotype record for an employee hiring or an applicant data entry action. Infotypes with time constraint A may not be deleted.

Time Constraints B: Only one record may ever exist for this infotype. It is valid from 01/01/1800 to 12/31/9999. Splitting is not permissible. Infotypes with time constraint B may be deleted.

Time Constraints T: The time constraint varies depending on the subtype.

For the Addresses infotype (0006), you can assign a different time constraint for each subtype. In this way, you can make sure that a main address always exists for the employee and you can also enter temporary residences, if necessary.

Time Constraints Z: Refers to time management infotypes. The time constraint for these infotypes depends on the time constraint class defined in view V_T554S_I Absence: General Control. Collision checks are defined in view V_T554Y  Time Constraint Reaction.