PRIMARY KEY (`id`) USING BTREE,指定id列为主键，使用B树作为索引。
主键索引 PRIMARY KEY 全文索引 FULLTEXT NORMAL 表示普通索引,大多数情况下都可以使用 UNIQUE 表示唯一的,不允许重复的索引,如果该字段信息保证不会重复例如身份证号用作索引时,可设置为unique PRIMARY KEY Primary Key是拥有自动定义的Unique约束,但是每个表中可以有多个Unique约束,但是只能有一个Primary Key约束。 FU...
Primary Key(聚集索引):InnoDB存储引擎的表会存在主键(唯一非null),如果建表的时候没有指定主键,则会使用第一非空的唯一索引作为聚集索引,否则InnoDB会自动帮你创建一个不可见的、长度为6字节的row_id用来作为聚集索引; 单列索引:单列索引即一个索引只包含单个列; 联合索引:组合索引指在表的多个字段组合上创建的...
PRIMARY KEY (`ID_MSG`,`RECEIVED_DATE`), KEY `Idx_NUM_CERTIFICATE` (`NUM_CERTIFICATE`) USING BTREE, KEY `Idx_ID_CONVERSATION` (`ID_CONVERSATION`) USING BTREE, KEY `Idx_TREATMENT_STATE` (`TREATMENT_STATE`) USING BTREE, KEY `Idx_CHECKED_RESULT` (`CHECKED_RESULT`) ...
1. Use the .ini file (the configparser package of Python can parse this type of configuration file) to save the configuration information about the database connection. 2. Add SSL connection parameters ca, key and cert to the connection options. ...
Why, and when do you use a universally unique identifier (UUID) as a primary key in a database?Can create records concurrently because it does not have to wait for the next ID like in sequential ID. So multiple machines can generate them independently which means potentially faster write. ...
I have an InnoDB table with a long varchar primary key, and when I do a “select id…” query, the results do not return ordered by id. I can think of 2 possible reasons: 1) this table has previously been converted to MyISAM and back to InnoDB, but has been modified much since ...
PRIMARY KEY CLUSTERED ([ID]) WITH (FILLFACTOR = 100) Would this have been also correct - without the CLUSTERED key word? ALTER TABLE [ClusterKeyColumnsTest] ADD CONSTRAINT [PK_ClusterKeyColumnsTest] PRIMARY KEY ([ID]) There are some examples here: https://msdn.microsoft.com/en-us/library...
I'm running Rails 4.0.0.rc1 and have a table that uses UUID as primary key: class CreateWebLinks < ActiveRecord::Migration def change create_table :web_links, id: :uuid do |t| t.boolean :active, default: true t.string :url, null: false, default: "http://" t.string :title, nul...
id: 1 select_type: SIMPLE table: myTable type: ALL possible_keys: NULL key: NULL key_len: NULL ref: NULL rows: 1803 Extra Using: filesort To prove that I really have assigned the primary key, I also made a "SHOW INDEX FROM myTable", giving the following info: Tab...