Elementary Data Types - User-Defined

Elementary Data Types - User-Defined

User-defined elementary data types are based entirely on predefined elementary data types. You define your own data types using the TYPES statement.

User-defined elementary data types make your programs easier to read and maintain:

If, for example, you often need to use a certain set of data types in your programs, you can ensure that you are always working with the same data types by creating an include program for the type definition (see INCLUDE programs) or by defining the data types in a type group in the ABAP Dictionary (see Type Groups).

To make the data types easier to understand and more recognizable, you can give them descriptive names.

After assigning a user-defined data type to several data objects, you change the data type of all these data objects in a single operation by changing the definition of the data type in the TYPES statement.

TYPES: NUMBER TYPE I,
LENGTH TYPE P DECIMALS 2,
CODE(3) TYPE C.
.......
DATA: NO_FLIGHTS TYPE NUMBER,
NO_PASSENGERS TYPE NUMBER,
      DISTANCE TYPE LENGTH,
HEIGHT TYPE LENGTH,
....
      CITY_CODE TYPE CODE,
COUNTRY_CODE TYPE CODE,
     ......

In this example, a data type called NUMBER is defined. It is the same as the predefined data type I, except it has a different name to make the program easier to read.

Also defined in this example is a data type LENGTH which is based on the predefined elementary data type P. LENGTH is defined with a given number of decimals. If it becomes necessary to change the accuracy of length specifications, for example, you only have to change the TYPES statement in the program.

A third data type, CODE, is also defined. CODE is based on the predefined type C, with a given length of 3.