Php 无法从数据库中选择列,常量已定义
当我试图从数据库中选择数据库时,我遇到了一个问题 我正在使用以下代码:Php 无法从数据库中选择列,常量已定义,php,mysql,Php,Mysql,当我试图从数据库中选择数据库时,我遇到了一个问题 我正在使用以下代码: include($_SERVER['DOCUMENT_ROOT'].'/central/inc/db.php'); $SQLSelect = $odb -> query("SELECT * FROM `status_testadores` ORDER BY `ID` DESC"); while ($show = $SQLSelect -> fetch(PDO::FETCH_ASSOC)) { $rowI
include($_SERVER['DOCUMENT_ROOT'].'/central/inc/db.php');
$SQLSelect = $odb -> query("SELECT * FROM `status_testadores` ORDER BY `ID` DESC");
while ($show = $SQLSelect -> fetch(PDO::FETCH_ASSOC))
{
$rowID = $show['ID'];
$sv1_db = $show['server_1'];
}
并返回以下错误:
Notice: Constant DB_HOST already defined in /Applications/MAMP/htdocs/central/inc/db.php on line 2
Notice: Constant DB_NAME already defined in /Applications/MAMP/htdocs/central/inc/db.php on line 3
Notice: Constant DB_USERNAME already defined in /Applications/MAMP/htdocs/central/inc/db.php on line 4
Notice: Constant DB_PASSWORD already defined in /Applications/MAMP/htdocs/central/inc/db.php on line 5
之所以发生这种情况,是因为我必须在标题中包含与sql db建立连接的db.php文件,但现在我需要在侧栏中包含该文件,以便在其中显示数据库数据,是否有一种方法可以连接到数据库而不出现这些错误?您应该使用include\u一次,而不是include,因为定义了常量的文件只应包含一次
将代码更改为:
include_once($_SERVER['DOCUMENT_ROOT'].'/central/inc/db.php');
$SQLSelect = $odb -> query("SELECT * FROM `status_testadores` ORDER BY `ID` DESC");
while ($show = $SQLSelect -> fetch(PDO::FETCH_ASSOC))
{
$rowID = $show['ID'];
$sv1_db = $show['server_1'];
}
您应该使用include_一次,而不是include,因为定义了常量的文件只应该包含一次
将代码更改为:
include_once($_SERVER['DOCUMENT_ROOT'].'/central/inc/db.php');
$SQLSelect = $odb -> query("SELECT * FROM `status_testadores` ORDER BY `ID` DESC");
while ($show = $SQLSelect -> fetch(PDO::FETCH_ASSOC))
{
$rowID = $show['ID'];
$sv1_db = $show['server_1'];
}
非常感谢,它成功了,我不得不在标题栏和边栏上添加一次_!非常感谢,它成功了,我不得不在标题栏和边栏上添加一次_!