Question

Code-

$col1->insert("_id" => '100',
    "results" => {
        "result" => "1",
        "when" => "sunday"  
    }
);  

the error is-

Can't use string ("100") as a HASH ref while "strict refs" in use at /usr/lib64/perl5/site_perl/5.8.8/x86_64-linux-thread-multi/MongoDB/Collection.pm line xyz.

What is wrong here?

Answer 1

The insert method in MongoDB::Collection wants a hash-ref, not a list. You want to say this:

$col1->insert({
    "_id" => '100',
    "results" => {
        "result" => "1",
        "when" => "sunday"  
    }
});

Note the ({ and }). The insert method actually takes hash-ref arguments. So inside insert, it will do something like this:

my ($self, $obj, $opts) = @_;
if($opts) {
    # Do things like $opts->{multi} ...
}

But your original call will put '_id' in $obj and '100' in $opts and that’s where your error message comes from. Keep in mind that => is just another way of saying , so your insert call was really:

$col1->insert("_id", '100', "results', { ... });