What are some features of a unique secondary key? Note: There are 2 correct answers to this question.

What are some features of a unique secondary key? Note: There are 2 correct answers to this question.
A . It is created when a table is filled.
B . It is updated when the modified table is read again.
C . It is created with the first read access of a table.
D . It is updated when the table is modified.

View Answer

Answer: CD

Explanation:

A unique secondary key is a type of secondary key that ensures that the key combination of all the rows in a table is unique. A unique secondary key has two purposes: firstly, to speed up access to the table, and secondly, to enforce data integrity1.

It is created with the first read access of a table: This is true. A unique secondary key is created when an internal table is filled for the first time using the statement READ TABLE or a similar statement. The system assigns a name and an index to each row of the table based on the key fields23.

It is updated when the modified table is read again: This is false. A unique secondary key does not need to be updated when the internal table content changes, because it already ensures data uniqueness. The system uses a lazy update strategy for non-unique secondary keys, which means that it delays updating them until they are actually accessed23. You cannot do any of the following:

It is created when a table is filled: This is false. As explained above, a unique secondary key is created only with the first read access of a table23.

It is updated when the modified table is read again: This is false. As explained above, a unique secondary key does not need to be updated when the internal table content changes23.

Reference: 1: Improving Internal Table Performance Using Secondary Keys – SAP Learning 2: [Secondary Key – ABAP Keyword Documentation – SAP Online Help] 3: [Secondary Table Key – ABAP

Keyword Documentation – SAP Online Help]