mysql启动
../bin/mysqld --defaults-file=./mysql/my.cnf --user=root
这里的--user是什么意思呢
mysql创建一个数据表student,需要有3个字段:id、name、age,其中指定唯一的索引是id。
mysql> create table student( -> id int not null, -> name varchar(16) not null, -> age int not null, -> unique index idx (id) -> );
查看数据表:
mysql> desc teacher; +-------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+-------------+------+-----+---------+-------+ | id | int(11) | NO | PRI | NULL | | | name | varchar(16) | NO | | NULL | | | age | int(11) | NO | | NULL | | +-------+-------------+------+-----+---------+-------+ 3 rows in set (0.00 sec)
查看索引
mysql> show index from teacherG; *************************** 1. row *************************** Table: teacher Non_unique: 0 Key_name: idx Seq_in_index: 1 Column_name: id Collation: A Cardinality: 0 Sub_part: NULL Packed: NULL Null: Index_type: BTREE Comment: Index_comment: 1 row in set (0.00 sec) ERROR: No query specified