Data structures such as B-trees speed up queries.
Indexes (B-tree, hash, bitmap, full-text) speed up searches by avoiding full table scans, at the cost of extra storage and slower writes. Use on columns in WHERE, JOIN and ORDER BY; composite indexes follow leftmost-prefix rule. EXPLAIN shows the plan.
Adding an index on email turns a 1-second scan into a millisecond lookup.
Indexes speed up lookups by keeping sorted or hashed access paths to the data, so queries stay fast as tables grow.
Data structures such as B-trees speed up queries.
Indexes speed up lookups by keeping sorted or hashed access paths to the data, so queries stay fast as tables grow.
Extra storage and slower writes, because the index must also be updated on every insert, update or delete.
A balanced tree index that supports both exact lookups and range queries efficiently on disk-based storage.
Typical applications include adding an index on the customer ID column to speed up order lookups, finding a row by serial number in a large inventory table and making a date range query on a log table fast enough for reports.
Study "Transactions and ACID" first (topic 77 of 104 in Software & Computing). It covers the groundwork this topic builds on.
Selectivity. Covering index. Index maintenance.
Adding an index on email turns a 1-second scan into a millisecond lookup.
The next topic is "NoSQL databases", which builds directly on this one.
It is classed as Advanced in Software & Computing (topic 78 of 104). It is an advanced topic. It assumes you are comfortable with the intermediate topics in Software & Computing.
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