index mysql

Environment construction1, to Apache download SOLR, Address: http://mirrors.hust.edu.cn/apache/lucene/solr/2. Unzip to a directory3. CD into D:\Solr\solr-4.10.3\example4. Execute the server by "Java-jar Startup.jar" SOLR will automatically run on

Describes how to use mysql to create an index and its advantages and disadvantages. Preface Index is a data structure that helps MySQL efficiently obtain data. It is critical for high performance, but people often forget or misunderstand it. The

Advantages and disadvantages of building indexes:Why do you create an index?This is because creating an index can greatly improve the performance of the system.First, by creating a unique index, you can guarantee the uniqueness of each row of data

Index functionIn addition to the ordered lookups mentioned above, the database uses a variety of fast location techniques to greatly improve the query efficiency. In particular, when the amount of data is very large and the query involves more than

http://blog.csdn.net/superit401/article/details/51291603Advantages and disadvantages of building indexes:Why do you create an index?This is because creating an index can greatly improve the performance of the system.First, by creating a unique index,

Create a unique index using SQL statements in the following format: Create unique index name on table name (column name 1, column Name 2 ...) For example, create a unique index ix_goodsmade_labour on the SID column of table Goodsmade_labour, with

One, MySQL commonly used commands:1. Connect to the database: mysql>mysql-uroot-p Enter, then passwordMysql-h 192.168.0.200-p 3306-u root-p2. mysql>status; View Run Environment information3. Show all databases: show databases;4. Switch the database

1.PRIMARY key (primary key index) Mysql>alter TABLE ' table_name ' ADD PRIMARY KEY (' column ')2.UNIQUE (unique index) mysql>alter TABLE ' table_name ' ADD UNIQUE (' column ')3.INDEX (normal index) mysql>alter TABLE ' table_name ' ADD index

Mysql Optimization in CentOS1. debug mysql Command method: mysql> explain select * from t1 \ G or: mysql> desc select * from t1 \ G mainly to view the following attributes:(1) Whether index is used for type(2) key Index name(3) number of rows

1. Add the primary key (primary key index)Mysql> alter table 'table _ name' add primary key ('column ')2. add UNIQUE (UNIQUE index)Mysql> alter table 'table _ name' add unique ('Column')3. Add an INDEX (Common INDEX)Mysql> alter table 'table _ name'

Advantages of creating an index in MySQL: 1. greatly accelerating data retrieval; 2. Creating a unique index to ensure the uniqueness of each row of data in the database table; 3. Accelerating the connection between tables Advantages of creating an

Mysql adds and deletes the field type, mysql Field Add a MySQL field: Alter table 'user _ movement_log 'Add column GatewayId int not null default 0 AFTER 'regionid' (AFTER which field is added) Delete field: alter table `user_movement_log` drop

Database index: Role of database index Advantages of index creation: 1. Greatly speed up data retrieval; 2. Create a unique index to ensure the uniqueness of each row of data in the database table; 3. Accelerate the connection between tables; 4.

MySQL adds a field: altertable 'user _ movement_log 'comment 'regionid' (after which field is added) Delete the field: altertable 'user _ movement_log' dropcolumnGatewayid adjust the field order: ALTERTABLE 'user _ movement_lo MySQL adds a field:

How does MYSQL add an index bitsCN.com? How to add an index for MYSQL 1. add the primary key (primary key index) Mysql> alter table 'Table _ name' add primary key ('column ') 2. add UNIQUE (UNIQUE index) Mysql> alter table 'Table _

1. Add the primary key (primary key index) Mysql> alter table 'table _ name' add primary key ('column ') 2. add UNIQUE (UNIQUE index) Mysql> alter table 'table _ name' add unique ( 'Column' ) 3. Add an INDEX (Common INDEX) Mysql> alter table '

Unindexed Mysql> alter table modulestatus drop index IMEI;Query OK, 457922 rows affected (4.29 Sec)Records: 457922 duplicates: 0 Warnings: 0 Mysql> select count (*) from modulestatus where IMEI like '1% ';+ ---------- +| Count (*) |+ ---------- +| 1,

1.PRIMARY key (primary key index)Mysql>alter TABLE ' table_name ' ADD PRIMARY KEY (' column ')2.UNIQUE (unique index)Mysql>alter TABLE ' table_name ' ADD UNIQUE (' Column ')3.INDEX (normal index)Mysql>alter TABLE ' table_name ' ADD INDEX index_name (

1. Add primary key (primary key index)Mysql>alter TABLE ' table_name ' ADD PRIMARY KEY (' column ')2. Add unique (unique index)Mysql>alter TABLE ' table_name ' ADD UNIQUE (' Column ')3. Add index (normal index)Mysql>alter TABLE ' table_name ' ADD

One, createCREATE Index to add a normal or unique index to a table.CREATE INDEX index_name ON table_name (column_list)CREATE UNIQUE INDEX index_name ON table_name (column_list)1) Build Multiple indexesCREATE INDEX Table Name _ Field name 1_ field