What is Data Element and why are they important?

Data Element Means

A data element is a data dictionary object in SAP. Data elements may generated and updated using transaction SE11. All data elements live in SE11. Data elements are significant items in the database that specify the semantic properties of table fields, such as online aid in certain areas. In other words, the data element determines how the table field appears for end-users and how it provides users with information when using the F1 assistance button in a table field.

Explains Data Element

Two kinds of data items are available:
Primary elements of data:
Defined by the data type and length built-in values
Reference Elements of Data:
Use reference variables that have mostly utilized in other ABAP objects.

By referencing the TYPE keyword, ABAP applications can utilize data components. Thus, in an ABAP program, the variables might take the features or qualities of the data components referred to.
Before generating new data elements, it has usually recommended utilizing the build of SAP data elements.

Features

Either a component type or a reference type has described in a data element.
The integrated data type, length, and a number of decimal places define a basic type. These characteristics can be either explicitly specified in the component of the material or a domain copy.
A kind of reference determines the types of ABAP variables.

A kind of reference determines the types of ABAP variables.
Input on the significance of a table field or structural component. Information on modifying the relevant screen field may assigned to a component of the material. All screen fields referring to the Component of material are provided with that information automatically. This information comprises showing the field in the input templates with the text keyword, column headings for listing the content of the table (see Labels), and output editing with parameter IDs.

For online field documentation, this is also true. The input template field text shown in the helping field (F1 help) originates from the Component of the material. Input template field See Documentation and Documentation Status for further information.

Example

The column CONN-ID of the SBOOK table corresponds to the data element S CONN-ID. The database component receives its technical properties from the S CONN-ID domain (NUMC data type, length 4). S CONN-ID Data Element provides the technical characteristics and meanings (long text assigned and brief explication text) of the CONN-ID field (and all other fields that refer to this data element).
In the ABAP program with the statement:

a variable with the data element type S CONN ID may defined:

DATA CONN-ID TYPE S_CONN_ID

See the image below for a clearer grasp of this scenario.

Data Element