How do you insert into mongoDB with specific data type in Perl?

Question

In MySQL for example you have data types such as varchar, int, etc. I googled and found http://docs.mongodb.org/manual/core/document/#bson-types page. It seems like with string you just use '' or "". Integers seem to be automatically recognized without specifing the type. How would inserting something like this into mongoDB collection in Perl look like?

Example:
{
 "Name" : "John"
 "Age" :   20
 "Weight" : 180.5
 "Dateofbirth" : 01/01/1990
}

The reason why I want data type specified in the db is that I can use operators to compare numbers for example. If it is text I cannot do that. So far I am thinking in Perl:

$my_collection->insert({
                        'Name' : "$Name",
                        'Age'  : $age,
                         'Weight':$weight,
                         'Dateofbirth': $datevar, 
                       } );

In the above code I am not sure how to specify the data type. For example to tell Weight is Double not integer or string.

friedo · Accepted Answer · 2013-01-17 19:49:13Z

1

For numeric types, the Perl MongoDB driver will go by whatever Perl thinks the number is. Perl has an internal flag for keeping track of whether something is a float or an int. The MongoDB driver will use 32 or 64-bit ints depending on your platform. If it looks like a string to Perl, it will be stored as a string in MongoDB.

For date types, you need to wrap the date in a DateTime object, or DateTime::Tiny if you use the dt_type attribute.

answered Jan 17, 2013 at 19:49

friedo

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7 Comments

DoodleKana Over a year ago

so it makes no difference how I use "$age" vs $age in $my_collection->insert statement? I was thinking that is how MongoDB driver knows to treat the field as string or number by that double or single quotes.

jordanm Over a year ago

Perl could think the number is a string. For JSON encoding, I have a habit of always adding "0" to a number first.

friedo Over a year ago

@DoodleKana, the MongoDB driver doesn't know about whether you used double quotes or not. It just gets an *SV (scalar value) structure, and uses the Perl API to find out if Perl thinks it's a string or a number.

Ken Williams Over a year ago

Unfortunately this isn't a full answer - for example, if a person had a Weight of 180 instead of 180.5, I see no way to coerce it to a float (SvNOK) except adding 1e-50 to it or something.

friedo Over a year ago

@KenWilliams, yes, sadly forcing an IV or PV to NV is rather difficult. I don't know of a good or idiomatic way to do it.

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sid_com · Accepted Answer · 2014-04-10 11:48:33Z

1

Use the looks_like_number parameter in the Perl MongoDB driver

use MongoDB::BSON $MongoDB::BSON::looks_like_number = 1;

https://metacpan.org/pod/MongoDB::BSON#looks_like_number

edited Apr 10, 2014 at 11:48

sid_com

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answered Sep 23, 2013 at 18:15

Jackie Shephard

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