为什么我的 Perl DBI 查询在 CGI 脚本中不返回任何结果？
我是第一次使用 DBI（刚开始使用 Perl [2 周]），我似乎无法从数据库中获得任何结果。这就是我所拥有的：
if( defined( $get{findAllPages} ) && defined( $post{ki} ) ){
my ($database, $hostname, $port, $password, $user );
$database = "#########";
$hostname = "localhost";
$password = "#########";
$user = "###########";
my $KI = $post{ki};
# connect to the database
my $dsn = "DBI:mysql:database=$database;host=$hostname;";
my $dbh = DBI->connect($dsn, $user, $password);
my $sth = $dbh->prepare("SELECT * FROM accounts WHERE KI = '" . $dbh->quote($KI) . "' ") or die "Could not select from table";
$sth->execute();
if( $sth->rows != 0 ) {
my $ref = $sth->fetchrow_hashref();
my $domain = $ref->{website};
my $DB_username = $ref->{db_name};
my $DB_password = $ref->{db_pass};
$sth->finish();
$dbh->disconnect();
print "domian: " . $domain . "<br />\n";
chomp(my $url = trim($domain));
就目前情况而言，它检查 KI 是否正确，然后检查有效的行数。我无法开始工作的是从数组返回值；
my $ref = $sth->fetchrow_hashref();
my $domain = $ref->{website};
my $DB_username = $ref->{db_name};
my $DB_password = $ref->{db_pass};
如果有人能让我知道我哪里出错了，我将不胜感激。
I'm using DBI for the first time (and not long started Perl [2 weeks]) and I can't seem to get any results from the database. Here's what I have:
if( defined( $get{findAllPages} ) && defined( $post{ki} ) ){
my ($database, $hostname, $port, $password, $user );
$database = "#########";
$hostname = "localhost";
$password = "#########";
$user = "###########";
my $KI = $post{ki};
# connect to the database
my $dsn = "DBI:mysql:database=$database;host=$hostname;";
my $dbh = DBI->connect($dsn, $user, $password);
my $sth = $dbh->prepare("SELECT * FROM accounts WHERE KI = '" . $dbh->quote($KI) . "' ") or die "Could not select from table";
$sth->execute();
if( $sth->rows != 0 ) {
my $ref = $sth->fetchrow_hashref();
my $domain = $ref->{website};
my $DB_username = $ref->{db_name};
my $DB_password = $ref->{db_pass};
$sth->finish();
$dbh->disconnect();
print "domian: " . $domain . "<br />\n";
chomp(my $url = trim($domain));
As it stands it checks to see if KI is correct and then checks row amount which works. The bit I can't get to work is returning values from the array;
my $ref = $sth->fetchrow_hashref();
my $domain = $ref->{website};
my $DB_username = $ref->{db_name};
my $DB_password = $ref->{db_pass};
If anyone can let me know where I am going wrong it would be much appreciated.
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尝试使用 DBI 的错误处理来查看问题所在。请参阅编程 Perl DBI，第 4 章（错误处理）或 Perlmonks 上的“DBI::mysql 错误处理” 供参考。
Try to use DBI's error handling to see what's wrong. See Programming the Perl DBI, chapter 4 (Error handling) or "DBI::mysql error handling" on Perlmonks for references.
当我看不到发生了什么时，我经常做的事情是：
使用 Data::Dumper;
我的 $ref = $sth->fetch();
打印转储器$ref；
您将看到数据结构布局。有时，这是一个数组或散列索引不正确的问题。
What I often do when I can't see what is going on:
use Data::Dumper;
my $ref = $sth->fetch();
print Dumper $ref;
and you'll see the data structure layout. Sometimes it is a matter of incorrect indexing into an array or hash.