DBA: Multiple ways to select MySQL database

First, the command line mode

MySQL [(none)]> show databases;        #未选择数据库前，显示（none）表示在数据库跟路径下+--------------------+| Database           |+--------------------+| information_schema || mysql              || performance_schema || sys                || viewtest           |+--------------------+5 rows in set (0.02 sec)MySQL [(none)]> use viewtest;   Database changedMySQL [viewtest]>                             #选择数据库后，就会显示你当前的数据库名称

Second, PHP way to select MySQL Database

Grammar:
mysqli_select_db (Connection,dbname)

Instance operations:

[[email protected] web]# cat query.php<?$dbhost = ‘localhost:3306‘;$dbuser = ‘root‘;$dbpass = ‘000000‘;$conn = mysqli_connect($dbhost,$dbuser,$dbpass);if ( ! $conn){    die(‘连接失败：‘ . mysqli_error($conn));}echo ‘连接数据库成功!!!‘;mysqli_select_db($conn,‘viewtest‘);mysqli_close($conn);?>[[email protected] web]#

：
1.

2.

DBA: Multiple ways to select MySQL database