maxdb_select_db
maxdb::select_db
(PECL maxdb >= 1.0)
maxdb_select_db -- maxdb::select_db — Selects the default database for database queries
说明
maxdb_select_db (
resource
$link ,
string $dbname ) :
bool
The maxdb_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.
Note:
This function should only be used to change the default database for the connection. You can select the default database with 4th parameter in maxdb_connect().
返回值
成功时返回 TRUE， 或者在失败时返回 FALSE。
范例
Example #1 面向对象风格
<?php
$maxdb = new maxdb("localhost", "MONA", "RED", "DEMODB");
/* check connection */
if (maxdb_connect_errno()) {
printf("Connect failed: %s\n", maxdb_connect_error());
exit();
}
/* return name of current default database */
if ($result = $maxdb->query("SELECT SERVERDB FROM USERS WHERE USERNAME='MONA'")) {
$row = $result->fetch_row();
printf("Default database is %s.\n", $row[0]);
$result->close();
}
/* change db to non existing db */
$maxdb->select_db("XXXXXXXX");
/* return name of current default database */
if ($result = $maxdb->query("SELECT SERVERDB FROM USERS WHERE USERNAME='MONA'")) {
$row = $result->fetch_row();
printf("Default database is %s.\n", $row[0]);
$result->close();
}
$maxdb->close();
?>
Example #2 过程化风格
<?php
$link = maxdb_connect("localhost", "MONA", "RED", "DEMODB");
/* check connection */
if (maxdb_connect_errno()) {
printf("Connect failed: %s\n", maxdb_connect_error());
exit();
}
/* return name of current default database */
if ($result = maxdb_query($link, "SELECT SERVERDB FROM USERS WHERE USERNAME='MONA'")) {
$row = maxdb_fetch_row($result);
printf("Default database is %s.\n", $row[0]);
maxdb_free_result($result);
}
/* change db to non existing db */
maxdb_select_db($link, "XXXXXXXX");
/* return name of current default database */
if ($result = maxdb_query($link, "SELECT SERVERDB FROM USERS WHERE USERNAME='MONA'")) {
$row = maxdb_fetch_row($result);
printf("Default database is %s.\n", $row[0]);
maxdb_free_result($result);
}
maxdb_close($link);
?>
以上例程的输出类似于：
Default database is <...>. Warning: maxdb_select_db(): -10709 Connection failed (RTE:database not running) <...> Warning: maxdb_query(): -10821 Session not connected [] <...> Warning: maxdb_close(): -10821 Session not connected [] <...>
参见
- maxdb_connect() - Open a new connection to the MaxDB server
- maxdb_real_connect() - Opens a connection to a MaxDB server
