Fields
The following illustration shows the Fields table for the sample context DEMO_TRAVEL:
These, in turn, can become input parameters for further modules. You can enter new modules in the table directly, or fill it automatically by creating fields in the
Modules table. You can delete all unneeded fields from the context. 
All fields in a context must have a reference to the ABAP Dictionary.
To edit the table, use the selection column and the pushbuttons on the left hand side of the table.
The table columns have the following meanings:
The field names which you use to address the fields in the context.
The Dictionary reference for the field. This can be a column of a database table or structure or a type in a type group.
The short text for the field from the ABAP Dictionary.
You can enter default values for key fields in this column. If you do this, the key fields of each instance of the context which you create in an application program will already be supplied with these values.
In this column, you specify the type of reference between the field and the ABAP Dictionary. Enter L if the field refers to a database table or structure (LIKE), or T if the field refers to a type in a type group (TYPE). The system will normally assign the correct value automatically.