php MySQL database selection

After you connect to the MySQL database, there may be multiple databases can operate, so you need to select the database you want to operate.

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Select the MySQL database from the command prompt window

In the mysql> prompt window can be very simple to select a specific database. You can use SQL commands to select the specified database.

Examples

The following examples selected database RUNOOB:

 

[root@host]# mysql -u root -p
Enter password:******
mysql> use RUNOOB;
Database changed
mysql>

After executing the above command, you have successfully chosen RUNOOB database, the database will be executed in RUNOOB in subsequent operations.

Note: All database names, table names, table fields are case sensitive. So you need to enter the correct name when using SQL commands.

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MySQL database using PHP script selection

PHP provides functions mysqli_select_db to select a database. After performing the function returns TRUE if successful, otherwise FALSE.

grammar

mysqli_select_db(connection,dbname);

 

parameter	description
connection	essential. MySQL provisions connection to use.
dbname	Necessary, to use the default database specified.

Examples

The following example shows how to use mysqli_select_db function to select a database:

? < PHP
 $ dbhost = 'localhost: 3306';   // MySQL server host address 
$ dbuser = 'root';             // MySQL username 
$ dbpass = '123456';           // MySQL username and password 
$ conn = mysqli_connect ( $ dbhost , $ dbuser , $ dbpass );
 IF (! $ conn )
{
    Die ( 'connection failed:'. mysqli_error ( $ Conn ));
}
echo '连接成功';
mysqli_select_db($conn, 'RUNOOB' );
mysqli_close($conn);
?>