how can i pass perl variable in sql file in perl script

Question

here i have 3 variable in perl and im passing those variable in one db.sql file in sql query line then executing that db.sql file in same perl file but it's not fetching those variable.

$patch_name="CS2.001_PROD_TEST_37987_spyy";
$svn_url="$/S/B";
$ftp_loc="/Releases/pkumar";
open(SQL, "$sqlfile") or die("Can't open file $sqlFile for reading");
while ($sqlStatement = <SQL>) 
{
   $sth = $dbh->prepare($sqlStatement) or die qq("Can't prepare $sqlStatement");

   $sth->execute() or die ("Can't execute $sqlStatement");
}
close SQL;
$dbh->disconnect;

following is the db.sql file query

insert into branch_build_info(patch_name,branch_name,ftp_path)
values('$patch_name','$svn_url','$ftp_loc/$patch_name.tar.gz');

pls help me how can i pass the variable so that i can run more the one insert query at a time.

Answer 1

If you can influence the sql-file, you could use placeholders

insert into ... values(?, ?, ?);

and then supply the parameters at execution:

my $ftp_path = "$ftp_loc/$patch_name.tar.gz";
$sth->execute( $patch_name, $svn_url, $ftp_path) or die ...

That way you would only need to prepare the statement once and can execute it as often as you want. But I'm not sure, where that sql-file comes from. It would be helpful, if you could clarify the complete workflow.

Answer 2

there's a few problems there - looks like you need to read in all of the SQL file to make the query, but you're just reading it a line at a time and trying to run each line as a separate query. The <SQL> just takes the next line from the file.

Assuming there is just one query in the file, something like the following may help:

open( my $SQL_FH, '<', $sqlfile)
   or die "Can't open file '$sqlFile' for reading: $!"; 

my @sql_statement = <$SQL_FH>;

close $SQL_FH;   

my $sth = $dbh->prepare( join(' ',@sql_statement) )
   or die "Can't prepare @sql_statement: $!";

$sth->execute();

However, you still need to expand the variables in your SQL file. If you can't replace them with placeholders as already suggested, then you'll need to either eval the file or parse it in some way...

Answer 3

You can use the String::Interpolate module to interpolate a string that's already been generated, like the string you're pulling out of a file:

while ($sqlStatement = <SQL>) 
{
   my $interpolated = new String::Interpolate { patch_name => \$patch_name, svn_url => \$svn_url, ftp_loc => \$ftp_loc };
   $interpolated->($sqlStatement);

   $sth = $dbh->prepare($interpolated) or die qq("Can't prepare $interpolated");

   $sth->execute() or die ("Can't execute $interpolated");
}

Alternately, you could manually perform replacements on the string to be interpolated:

while ($sqlStatement = <SQL>) 
{
   $sqlStatement =~ s/\$patch_name/$patch_name/g;
   $sqlStatement =~ s/\$svn_url/$svn_url/g;
   $sqlStatement =~ s/\$ftp_loc/$ftp_loc/g;

   $sth = $dbh->prepare($sqlStatement) or die qq("Can't prepare $sqlStatement");

   $sth->execute() or die ("Can't execute $sqlStatement");
}