mysqli::select_db

mysqli_select_db

(PHP 5)

mysqli::select_db -- mysqli_select_dbSelects the default database for database queries

Descrição

Estilo orientado à objeto

bool mysqli::select_db ( string $dbname )

Estilo procedural

bool mysqli_select_db ( mysqli $link , string $dbname )

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().

Parâmetros

link

Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()

dbname

The database name.

Valor Retornado

Retorna TRUE em caso de sucesso ou FALSE em caso de falha.

Exemplos

Exemplo #1 mysqli::select_db() example

Estilo orientado à objeto

<?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();
?>

Estilo procedural

<?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);
?>

Os exemplos acima irão imprimir:

Default database is test.
Default database is world.

Veja Também

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User Contributed Notes 2 notes

up
-1
pjasiulewicz at gmail dot com
3 years ago
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.
up
-2
hwalker1 at btopenworld dot com
11 months ago
Note that in the second example, if the database "world" does not exist, the database selected does not change. You may need to add additional code to ensure that you are connected to the correct database.
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