Design and use of MySQL index

I. Overview of the Index

The tables for the MyISAM and InnoDB storage engines are created by default as Btree indexes. MySQL currently does not support function indexing (supported by version 5.7), but it supports prefix indexing, which is the index of the first n characters of an indexed field. The length of the prefix index is related to the storage engine, and for MyISAM storage engine tables, the index prefix length can be up to 1000 bytes long , while for the InnoDB Storage engine table, the index prefix length is 767 bytes maximum. Note that the prefix limit should be measured in bytes, whereas the prefix length in the CREATE TABLE statement is interpreted as the number of characters . Be sure to consider when specifying a prefix length for a column that uses multibyte character sets.

MySQL also supports the full-text (fulltext) index, which can be used for full-text search. Indexes are always made for an entire column, and local (prefix) indexes are not supported.

Full-Text index more information:

Http://www.cnblogs.com/tommy-huang/p/4483684.html

http://blog.csdn.net/bbirdsky/article/details/45368897

Design and use of MySQL index