mysqli::rollback
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
Описание
Object oriented style (method):
bool mysqli::select_db
( string $dbname
)
Procedural style:
Selects the default database to be used when performing queries against the database connection.
Забележка: 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().
Параметри
- link
-
Само за процедурния стил: Идентификатор на връзката върнат от mysqli_connect() или mysqli_init()
- dbname
-
The database name.
Връщани стойности
Връща TRUE при успех или FALSE при неуспех.
Примери
Example #1 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();
?>
Example #2 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);
?>
Примерът по-горе ще изведе:
Default database is test. Default database is world.
Вж. също
- mysqli_connect() - Open a new connection to the MySQL server
- 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 08:30