Database optimization tutorial (6) index-related operations, tuning Indexes

Database optimization tutorial (6) index-related operations, tuning Indexes
Iii. Index

3. Index-related operations

In the previous section, we introduced the functions and types of indexes. This section describes the operations related to indexes!

1) Add an index

I have already introduced it. Here I will summarize it.

Add primary key index

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1. Create table aaa
2. (Id int unsigned primary key auto_increment,
3. Name varchar (32) not null defaul '');
5. Alter table name add primary key (column name );

Add Common Index

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1. Create index name on table (column name 1, column name 2 );

Add a unique index

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1. Create table ddd (id int primary key auto_increment, name varchar (32) unique );
3. Create unique index name on table name (list ..);

Add full-text index

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1. Create table articles (
2. Id int unsigned AUTO_INCREMENT not null primary key,
3. Title VARCHAR (200 ),
4. Body TEXT,
5. FULLTEXT (title, body)
6. ) Engine = myisam charset utf8;
8. Alter table articles add fulltext (title, body );

2) query Indexes

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1. Show index from emp \ G

3) delete an index

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1. Drop index name on table name;

4) modify the index

Delete first, and then create