MySQL and PHP
Copyright 1997-2021 the PHP Documentation Group.
mysqli::select_db
mysqli_select_db
Selects the default database for database queries
Object oriented style
public bool mysqli::select_db(string dbname);
Procedural style
bool mysqli_select_db(mysqli link,
string dbname);
Selects the default database to be used when performing queries against the database connection.
This function should only be used to change the default
database for the connection. You can select the default
database with 4th parameter in
mysqli_connect
.
link
Procedural style only: A link identifier returned by
mysqli_connect
or
mysqli_init
dbname
The database name.
Returns true
on success or
false
on failure.
Example 3.63 mysqli::select_db
example
Object oriented style
<?php $mysqli = new mysqli("localhost", "my_user", "my_password", "test"); /* check connection */ if (mysqli_connect_errno()) { printf("Connect failed: %s\n", mysqli_connect_error()); exit(); } /* return name of current default database */ if ($result = $mysqli->query("SELECT DATABASE()")) { $row = $result->fetch_row(); printf("Default database is %s.\n", $row[0]); $result->close(); } /* change db to world db */ $mysqli->select_db("world"); /* return name of current default database */ if ($result = $mysqli->query("SELECT DATABASE()")) { $row = $result->fetch_row(); printf("Default database is %s.\n", $row[0]); $result->close(); } $mysqli->close(); ?>
Procedural style
<?php $link = mysqli_connect("localhost", "my_user", "my_password", "test"); /* check connection */ if (mysqli_connect_errno()) { printf("Connect failed: %s\n", mysqli_connect_error()); exit(); } /* return name of current default database */ if ($result = mysqli_query($link, "SELECT DATABASE()")) { $row = mysqli_fetch_row($result); printf("Default database is %s.\n", $row[0]); mysqli_free_result($result); } /* change db to world db */ mysqli_select_db($link, "world"); /* return name of current default database */ if ($result = mysqli_query($link, "SELECT DATABASE()")) { $row = mysqli_fetch_row($result); printf("Default database is %s.\n", $row[0]); mysqli_free_result($result); } mysqli_close($link); ?>
The above examples will output:
Default database is test. Default database is world.
mysqli_connect
|
mysqli_real_connect
|