In databases, which term describes a method of storing data to make data easier to find when conducting searches on the data?

• A. Integer
• B. Index
• C. Instance
• D. Instantiation

Answer: (B)

An index is a data structure that speeds up data retrieval by providing quick access paths to the rows you want. It’s like the index at the back of a book: instead of scanning every page, you use the index to find the page numbers that contain the term you’re looking for. In a database, creating an index on a column (or set of columns) lets the system locate matching rows much more quickly when you run searches, such as a WHERE clause or a JOIN, and can also assist with sorting. Of course, maintaining the index takes extra storage and there’s some overhead when inserting, updating, or deleting rows because the index must be updated as well. But the payoff is faster searches on large datasets. The other terms—an integer is a numeric data type, an instance is a single object, and instantiation is the creation of that object—don’t describe a mechanism for speeding up searches.