如何将参数从 Perl 脚本传递到 SQL 脚本并从 Perl 脚本执行？

Question

I use Informix as database in Linux environment. I have a Perl script which should execute an SQL-script. Before execution, it should also pass all parameters to the SQL-script.

I can't figure out how to pass parameters to .sql script? It also does run but I get following error.

DBD::Informix::st fetchrow_array failed: SQL: -400: Fetch attempted on unopen cursor. at startSelectQuer.pl 

How can I realize this?

selectQuer.sql

DROP TABLE IF EXISTS tempTable;
SELECT * FROM 'informix'.systables INTO TEMP tempTable;

DROP TABLE IF EXISTS magic_ant;
 select * from  del_new
    where
       id    = $i_id       and
       year  = $i_year     and
       month = $i_month              
    into 
        temp magic_ant; 

    
    DROP TABLE IF EXISTS magic_buck;
    select * from  upper_new
    where
       id    = $i_id       and
       year  = $i_year     and
       month = $i_month              
    into 
        temp magic_buck; 

DROP TABLE IF EXISTS alleMagic;
select  * from  magic_ant
union
select  * from  magic_buck
into temp alleMagic;    

select lname, fname, ext from alleMagic;

startSelectQuer.pl

       #!/usr/bin/perl
use strict;
use warnings;
use DBI;
    
my ($ID)    = $_[0];
my ($YEAR)  = $_[1];
my ($MONTH) = $_[2];

my $BEG_ANT=801 ; 
my $END_ANT=803 ; 
my $BEG_BRU=802 ; 
my $END_BRU=900 ;

my($dbh, $sth, $query);

######################################################################
my $database = "$ENV{DBNAME}";         
my $user ="";                                                                                          
my $pass ="";                                                                                       
$dbh = DBI->connect("dbi:Informix:$database", $user, $pass);                                                  
######################################################################
die "failed to connect to MySQL database:DBI->errstr()" unless($dbh);

my $sqlFile = "/SQLSCRIPTS/selectQuer.sql";
open (SQL, "$sqlFile")   or die("Can't open file $sqlFile for reading");

# Loop though the SQL file and execute each and every one.
while (my $line = <SQL>) {

  chomp $line;
  $line = join(' ',split(' ',$line));
  if ((substr($line,0,2) ne '--') and (substr($line,0,3) ne 'REM')) {
     if (substr($line,- 1,1) eq ';') {
            $query .= ' ' . substr($line,0,length($line) -1);
            # replace with value
            replaceQueryWithValue($query);
            
           $sth = $dbh->prepare($query, {'ix_CursorWithHold' => 1}) 
          or die "prepare statement failed: $dbh->errstr()";
           $sth->execute() or die "execution failed: $dbh->errstr()";

           my $rows = $sth->rows;
            #loop through each row of the result set, and print it.
           if ($rows > 0) {
            # Getting error here as: DBD::Informix::st fetchrow_array failed:
            # SQL: -400: Fetch attempted on unopen cursor. 
              while(my @row = $sth->fetchrow_array) {
                 print qw($row[0]\t$row[1]\t$row[2]\n);
              }
           } else
              {
                  print "\nThere is no result for query: $query\n" ;
              }
            $query = ' ';
      } else {
                 $query .= ' ' . $line;    
          }
  }
}

# close data connection
$sth->finish;
$dbh->disconnect;

sub replaceQueryWithValue{
   $query =~ s/i_id/$ID/ig;
   $query =~ s/i_year/$YEAR/ig;
   $query =~ s/i_month/$MONTH/ig;
}

Answer 1

When asking a question like this, it's useful if you tell us exactly what isn't working as you expect it to. Does nothing happen? Do you get an error message? Does your computer burst into flames?

Without that, we're pretty much guessing. But I'm happy to have a guess here. I know nothing about Informix, but I would guess that you're seeing the "prepare statement failed" error. Is that right?

If so, it seems to be that you're trying to compile an SQL statement that looks like SQLSCRIPTS/selectQuer.sql - when actually, that is the name of a file that you should be opening and reading your SQL statement from.

Answer 2

I used $sth->fetch instead of $sth->fetchrow_array after execution of .sql as below.

  $sth = $dbh->prepare( "select * from alleMagic;" );
  $sth->execute;
    
   # Column binding is the most efficient way to fetch data
   my $rv = $sth->bind_columns(\$lname, \$fname, \$ext );
   while ($sth->fetch) {
       print "$lname, $fname, $ext \n";

   }