In SQL, which command(s) is(are) used to redefine an index’s future storage allocation A. ALTER INDEX B. REDEFINE INDEX C. MODIFY INDEX D. DO INDEX E. None of the above

The correct answer is A. ALTER INDEX.

The ALTER INDEX statement is used to modify the structure of an existing index. It can be used to add, drop, or change the columns in an index, or to change the storage allocation of an index.

The REDEFINE INDEX statement is used to drop and recreate an index with the same name and definition, but with different storage parameters.

The MODIFY INDEX statement is used to modify the storage allocation of an index without dropping and recreating it.

The DO INDEX statement is not a valid SQL statement.

Here is an example of how to use the ALTER INDEX statement to change the storage allocation of an index:

sql
ALTER INDEX my_index ON my_table REBUILD WITH (DATA_COMPRESSION = PAGE);

This statement will rebuild the index my_index on the table my_table, using page compression.