Data Elements vs. Domains

Lets start with explaining what are these two terms needed for.

When we are defining database tables within SAP, each and every field needs to contain specific type.

Lets say that we create a database table called Store. Along with other fields the store also needs to contain information when it is opened and closed.

In this case, let’s assume that 2 fields I have just described are called OPENED_AT and CLOSED_AT.

In order to store such information in that field and display its type in a humanly readable way, e.g. OPENED_AT field contains e.g. “Store Opened At” label, we need to define data element containing such information.

Both fields need to handle data in time format containing the information about time availability of the store – this is the domain.

Notice: Domain does not need to be created for each and every Data Element, because Data Element itself handles also technical information of its type. There are 2 common cases when we usually create domains for data elements (mentioned below in the article)

Data Element

Data Elements are semantic information about fields or components. They also contain technical attributes of the fields or components. The technical attributes of Data elements can be described either with Predefined Type or a reusable Domain.

A Data Element can be referenced in ABAP programs as TYPE. In the Declarations section, we can define variables in ABAP programs that take on attributes of a Data Element.

2 common ways to create Data Element

1. Transaction SE11

This is the standard way of creating Data Elements.

Choose “Data type” radio button, enter Data Element name, e.g. ZAS_DDIC_OPENED_AT, and click Create button.

Note: The data element’s name starts with ZAS. Why? Every customer object name in SAP must start with Z or Y. In ABAP Academy, we add the developer’s initial name right after Z or Y. AS is my initial name. All objects that I created to start with ZAS.

In “Data Type” tab, define technical detail of Data Element.

Right here you have 2 options:

If you have already defined a domain you can use it right here to define its data type (as shown in the image below).

Choose “Predefined Type” where you can manually define that you will use time type “TIMS” with length 6.

Notice: Both ways will technically work. Later in this article we will talk about the cases when we commonly use domains.

In “Field Label” tab, fill in all labels of the Data Element. By this we provide humanly readable way to understand users what type of data this data element contain.

Check syntax (CTRL +F2) and activate (CTRL+F3).

Data Element is created.

2. Transaction SE80

We as developers often look for the easiest and fastest ways on how to develop our solutions. Such a way of creating Data Elements is by using transaction SE80.

More about it in the article: How to Create Database a Database Table.

Domain

Domains are a technical description which can be used by more than one data elements with similar characteristics. Domain is assigned to Data Element. Fields that refer to the same domain are also changed when the domain is changed.

When To Create Domain?

There are two cases when we usually create domains.

Case 1: When creating fields of repeating data types

This is exactly the case of showing the difference between Data Elements and Domains from the beginning of this article.

Fields OPENED_AT and CLOSED_AT use exactly the same type of time. For this case, we create 2 different Data Elements for each field and 1 common domain.