How do you use a sorted internal table?

A sorted internal table in ABAP is designed to maintain its records in a specific order, which enhances performance for certain operations like searching or reading. To use a sorted internal table effectively, it is essential to declare a key at the time of its definition. This key determines the order in which the entries of the table will be organized and accessed. The key functions similarly to an index, ensuring that the table's records are kept in a sorted manner based on the specified key fields.

The declaration of a key is crucial because it dictates how the sorting will occur and how records are recognized and retrieved. This means that the access and manipulation of data within the sorted internal table are optimized based on the key you specify, making query operations more efficient.

To maintain the integrity of the sorted order upon insertion or changes to the internal table, the table uses mechanisms that ensure that elements are added in their appropriate positions based on the defined key. Thus, starting with a well-defined key is foundational for the operation of sorted internal tables in ABAP.