Indexes Matter-How Poor Index Management Can Ruin Query Performance
Ideally, database queries use the fewest possible resources: time, memory, bandwidth, etc. Lower resource consumption maps to better query performance. To find relevant data in a table, a database query relies on lookup operations, and a table index can help a query efficiently find the table values it needs. With an efficient, well-designed table index, a database query can find the table data it needs, avoiding the need to "scan"—or search through—all the table data.