7 terms
A B-tree index is a balanced, sorted tree of disk pages that lets a database find rows by key, range or order in a few page…
A clustered index stores table rows physically ordered by the index key, so the index leaf level holds the data itself and each table can have…
A composite index is a database index built on two or more columns in a fixed order, speeding queries that filter or sort on its leading…
A covering index is a database index that contains every column a query needs, so the query is answered from the index without reading the table.
A hash index is a database index that maps each key through a hash function to a bucket, giving fast equality lookups but no support for…
A non-clustered index is a separate sorted structure of key values and row pointers that speeds up lookups without changing table row order.
A query planner is the database component that chooses how to execute a SQL query, including which indexes, join methods and join order to use.