Developing Functions using MongoDB Console

Question

When running the query

db.graduates.find({student_id: '2010-01016'}).pretty()

, it returns a result.

Afterwards, I created a function:

function findStud(name,value){ return db.graduates.find({name:value}); }

However, while executing

findStud("student_id","2010-01016")

on the mongo shell, the results are not displayed.

Answer 1

Answer №1

To create a query object, you must use the key as the value in the name parameter and the value as the value in the parameter value.

function findStud(name,value){
var query = {};
query[name] = value;
return db.graduates.find(query); 
}

If you fail to do this, the name is automatically treated as a String literal, resulting in the query being executed as

db.graduates.find({"name":value});

. This incorrect search for a key named name with the specified value will cause the query to fail.

For more information, check out: Mongodb doesn't not update when I use like this

Answer 2

To create a query object, you must use the key as the value in the name parameter and the value as the value in the parameter value.

function findStud(name,value){
var query = {};
query[name] = value;
return db.graduates.find(query); 
}

If you fail to do this, the name is automatically treated as a String literal, resulting in the query being executed as

db.graduates.find({"name":value});

. This incorrect search for a key named name with the specified value will cause the query to fail.

For more information, check out: Mongodb doesn't not update when I use like this