In some situations its useful to use this function for changing databases in general. We've tested it in production environment and it seams to be faster with switching databases than creating new connections.
mysqli::select_db
mysqli_select_db
(PHP 5)
mysqli::select_db -- mysqli_select_db — Selects the default database for database queries
Descrizione
Stile orientato agli oggetti
bool mysqli::select_db
( string
$dbname
)Stile procedurale
Selects the default database to be used when performing queries against the database connection.
Nota:
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().
Elenco dei parametri
-
link -
Solo nello stile procedurale: un identificatore restituito da mysqli_connect() o mysqli_init()
-
dbname -
The database name.
Valori restituiti
Restituisce TRUE in caso di successo, FALSE in caso di fallimento.
Esempi
Example #1 mysqli::select_db() example
Stile orientato agli oggetti
<?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();
?>
Stile procedurale
<?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);
?>
I precedenti esempi visualizzeranno:
Default database is test. Default database is world.
Vedere anche:
- mysqli_connect() - Alias di mysqli::__construct
- mysqli_real_connect() - Opens a connection to a mysql server
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User Contributed Notes 1 note
pjasiulewicz at gmail dot com ¶
2 years ago