mysqli::rpl_query_type
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
Beschreibung
Objektorientierter Stil
bool mysqli::select_db
( string
$dbname
)Prozeduraler Stil
Selects the default database to be used when performing queries against the database connection.
Hinweis:
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().
Parameter-Liste
-
link -
Nur bei prozeduralem Aufruf: Ein von mysqli_connect() oder mysqli_init() zurückgegebenes Verbindungsobjekt.
-
dbname -
The database name.
Rückgabewerte
Gibt bei Erfolg TRUE zurück. Im Fehlerfall wird FALSE zurückgegeben.
Beispiele
Beispiel #1 mysqli::select_db() example
Objektorientierter Stil
<?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();
?>
Prozeduraler Stil
<?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);
?>
Die obigen Bespiele erzeugen folgende Ausgabe:
Default database is test. Default database is world.
Siehe auch
- mysqli_connect() - Alias von mysqli::__construct
- mysqli_real_connect() - Opens a connection to a mysql server
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User Contributed Notes
mysqli::select_db
pjasiulewicz at gmail dot com
27-Mar-2011 02:30