Describe the purpose of a database index and two common index types.

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Multiple Choice

Describe the purpose of a database index and two common index types.

A database index is a data structure that lets the system locate rows quickly by their indexed values, so it can find relevant records without scanning every row. This speeds up data retrieval and makes searches, lookups, and range queries much more efficient. Two common index types are B-tree indexes and bitmap indexes. A B-tree index keeps keys in a balanced tree, which preserves order and allows fast exact and range queries with logarithmic search time. A bitmap index uses a separate bit array for each distinct value, enabling rapid combination of conditions (using bitwise operations) and is especially effective for columns with few distinct values. Other options describe functions outside the purpose of indexing—data redundancy and access permissions—so they don’t fit the concept of speeding up searches.

A database index is a data structure that lets the system locate rows quickly by their indexed values, so it can find relevant records without scanning every row. This speeds up data retrieval and makes searches, lookups, and range queries much more efficient.

Two common index types are B-tree indexes and bitmap indexes. A B-tree index keeps keys in a balanced tree, which preserves order and allows fast exact and range queries with logarithmic search time. A bitmap index uses a separate bit array for each distinct value, enabling rapid combination of conditions (using bitwise operations) and is especially effective for columns with few distinct values.

Other options describe functions outside the purpose of indexing—data redundancy and access permissions—so they don’t fit the concept of speeding up searches.

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