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# mysqli_select_db

(PHP 5)

mysqli_select_db

(no version information, might be only in CVS)

mysqli->select_db -- Selects the default database for database queries

## Description

bool mysqli_select_db ( object link, string dbname)

The mysqli_select_db() function selects the default database (specified by the dbname parameter) to be used when performing queries against the database connection represented by the link parameter.

> 備注: 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().

## Return values

成功回傳`TRUE`失敗回傳`FALSE`。

## See also

mysqli_connect() mysqli_real_connect()

## Example

示範 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();
?>`

示範 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);
?>`

The above examples would produce the following output:

    Default database is test.
    Default database is world.

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