MySQL index details, MySQL index detailsI. Introduction to index basics 1.1
In MySQL, indexes are also called keys. They are a data structure that the storage engine uses to quickly find records.
Indexes are critical to good performance. Especially
Creating an index is the establishment of an index on one or more columns of a table to increase the speed of access to the table. There are 3 ways to create an index, the 3 ways to create an index when creating a table, to create an index on a
MySQL versions, for the Add index processing is different, there are three main types:
(1) Copy table methodThis is the earliest supported way to create an index INNODB. As the name suggests, creating indexes is done through temporary table copies.
MySQL indexing function
On the index column, in addition to the ordered lookup, the database can greatly improve the query efficiency by using a variety of fast positioning techniques. In particular, when the volume of data is very large and
MySQL index analysis and optimization indexes are used to quickly search for records with specific values. all MySQL indexes are saved as B-trees. If no index exists, MySQL must scan all the records of the entire table from the first record until
The concept of MySQL indexingAn index is a special kind of file (an index on a InnoDB data table is an integral part of a table space), and they contain reference pointers to all records in the datasheet. More generally, the database index is like a
MySQL 5-1 -- index bitsCN.com 1. MySQL has multiple rows that access tables. The most commonly used is sequential access and index access. Sequential access refers to browsing a table in one row, that is, full table scan. Disadvantage: it is very
An index is a special file (an index on an InnoDB data table is an integral part of a tablespace) that contains reference pointers to all records in the data table.
Indexing is not omnipotent!
Indexing speeds up data retrieval, but slows
With regard to the benefits of MySQL indexing, if the correct and reasonable design and use of the index MySQL is a Lamborghini, then there is no design and use of the index MySQL is a human tricycle. For tables with no indexes, a single table query
This article mainly summarizes the MySQL index operation methods, including creating indexes, rebuilding indexes, querying indexes, and deleting indexes. In the following example, 'table _ name' indicates the data table name, 'index _ name'
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