无法从 csv 文件中选择一列

Question

我使用 Perl 通过 DBI 连接到 DBD::CSV，连接运行良好，当我启动时

SELECT * FROM dp_id.csv 

它工作正常，但是当我想提取单列时。

my $dbh = DBI->connect ("dbi:CSV:", undef, undef, { f_dir => "." });

my $query = " SELECT DpName from dp_id.csv";


my $sth   = $dbh->prepare ($query);
$sth->execute ();

while (my @row = $sth->fetchrow_array)
{
    print @row,"\n";
}

我有这个错误

 Execution ERROR: No such column 'dpname' called from extract.pl at 20.
 [for Statement " SELECT DpName from dp_id.csv"] at extract.pl line 20.
 DBD::CSV::st fetchrow_array failed: Attempt to fetch row without a preceding execute () call or from 
 a non-SELECT statement [for Statement " SELECT DpName from dp_id.csv"] at extract.pl line 22.

这是 csv 文件的摘录：

kindOfInfo;DpName;TypeName;ID
interface;ALLARM;DPT_TS;344108
interface;POMP1;DPT_TS;7923082

Answer 1

默认情况下，DBD::CSV 假定您的文件以逗号分隔（因为这就是 CSV 中的“CS”代表:-)）

您的数据以分号分隔。所以你需要在创建连接时告诉 DBD::CSV 。

my $dbh = DBI->connect ("dbi:CSV:", undef, undef, {
  f_dir        => ".",
  csv_sep_char => ';', # This is the important line
});

否则，DBD 会将您的数据视为名称为“kindOfInfo;DpName;TypeName;ID”的单列。