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