Sparse Indexing 

In sparse index, index records are not created for every search key. An index record here contains a search key and an actual pointer to the data on the disk. To search a record, we first proceed by index record and reach at the actual location of the data. If the data we are looking for is not where we directly reach by following the index, then the system starts sequential search until the desired data is found.

in terms of data representation

Data science is a very innovative field

Use settngs

Both are databased. Mongo DB is in demand now.

Specialization is the reverse process of Generalization means creating new sub classes from an existing class.

Your superclass is a generalized class , but your subclass will be a specialized inheritor of your superclass. It becomes more specialized and less generalized as you move down the inheritance hierarchy .

Generalization

Generalization is the process of extracting shared characteristics from two or more classes, and combining them into a generalized superclass. Shared characteristics can be attributes, associations, or methods.

Specialization

If some new subclasses are created from an existing superclass to do specific job of the superclass, then it is known as specialization.

Naive bayes is a classification algorithm. It's based on conditional probability. It's called naive because it assumes that each and every variable is independent of one another.

Yes, you remove the attribute and then re-save() the object.

A namespace is designed to overcome this difficulty and is used as additional information to differentiate similar functions, classes, variables etc. with the same name available in different libraries. Using namespace, you can define the context in which names are defined. In essence, a namespace defines a scope.

The database profiler collects fine grained data about MongoDB write operations, cursors, database commands on a running mongod instance. You can enable profiling on a per-database or per-instance basis. The profiling level is also configurable when enabling profiling.

The database profiler writes all the data it collects to the system.profile collection, which is a capped collection. See Database Profiler Output for overview of the data in the system.profile documents created by the profiler.