Undefined
In this section, we will discuss the “undefined” datatype in MongoDB. This datatype was originally used in the early versions of MongoDB, but now it is deprecated and should not be used in new applications.
What is ‘undefined’?
An ‘undefined’ datatype in MongoDB is a data type that signifies that the value of a field has not been set or has been removed. It represents the absence of a value.
Why should it not be used?
In the newer versions of MongoDB, it is recommended to use the null
value for representing missing or undefined values in the database. Although the undefined
datatype is still supported for backward compatibility, it is advised to avoid the use of it, as the null
value is more widely accepted and understood.
Here is an example to show the difference between null
and undefined
:
{
"field1": null,
"field2": undefined
}
In this example, field1
has a null
value, while field2
has an undefined
value. However, it is recommended to use null
instead of undefined
to maintain better readability and compatibility.
Conclusion
In summary, while the ‘undefined’ datatype exists in MongoDB, it is now considered deprecated and should be avoided. Instead, it is suggested to use the null
value to represent fields with missing or undefined values in your database. This will ensure better compatibility and readability of your code when using MongoDB.