What are characteristics of secondary keys for internal tables? Select three correct answers.

The characteristic of secondary keys indicated in the selected answer reflects the flexible design of internal tables in ABAP. Multiple secondary keys can indeed be defined for any type of internal table—this includes standard tables, sorted tables, and hashed tables. Having multiple secondary keys allows developers to optimize data access patterns based on different attributes or columns, enhancing efficiency when querying or manipulating data based on those keys.

In addition to this, sorted secondary keys do not need to be unique, which allows for greater flexibility in handling records that may have the same values for the designated fields of the secondary key. This characteristic supports scenarios where data may have repeating entries depending on the context.

To summarize, the ability to define multiple secondary keys fosters a more dynamic and efficient use of internal tables in ABAP, allowing programmers to tailor data retrieval to meet their specific use cases.