Use ABAP_BOOL for Booleans

DATA has_entries TYPE abap_bool.

Don’t use the generic type char1. Although it is technically compatible it obscures the fact that we’re dealing with a Boolean variable.

Also avoid other Boolean types as they often have strange side effects, for example boolean supports a third value “undefined” that results in subtle programming errors.

In some cases you may need a data dictionary element, for example for DynPro fields. abap_bool cannot be used here because it is defined in the type pool abap, not in the data dictionary. In this case, resort to abap_boolean. Create your own data element if you need a custom description.

ABAP may be the one single programming language that does not come with a universal Boolean data type. However, having one is imperative. This recommendation is based on the ABAP Programming Guidelines.