mysqli_select_db

Selects the default database for database queries (PHP 5)
bool mysqli_select_db ( mysqli 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.

注意:

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().

返回值

如果成功则返回 TRUE，失败则返回 FALSE。

参见

mysqli_connect() 和 mysqli_real_connect().

范例

例 1324. Object oriented style

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<?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();
?>

例 1325. Procedural style

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<?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);
?>

上例将输出：

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Default database is test.
Default database is world.