Databases

Question 1

One of the goals in web development is data __________.

Answer 1

persistence

Question 2

Application processes stop at some point for 3 reasons:

Answer 2

1. Hardware/software failure
2. Need to upgrade or replace hardware
3. Need to update software

Question 3

Data can be stored in (2):

Answer 3

1. Flat files
2. Databases

Question 4

A NoSQL, open-source document based database.

Answer 4

MongoDB

Question 5

3 Features of MongoDB

Answer 5

1. High Performance
2. High Availability
3. Easy Scalability

Question 6

Working with _______ is commonplace in today’s programming languages.

Answer 6

objects

Question 7

Why not save objects in the datastore in a similar format?

Answer 7

Sabi ni chatgpt:
1. Datastore Efficiency and Compatibility
In-memory objects often contain methods, type annotations, and references unsuitable for storage.

Datastores are optimized for simpler, serializable formats like JSON, BSON, or SQL rows.

2. Serialization Requirements
   Data needs to be converted into a storable format (like maps or plain values). This process often drops non-serializable fields or complex types.
3. Cross-Platform or Cross-Language Interoperability
   Saving data in a universal format (e.g., JSON) ensures that different clients (mobile, web, backend) can read it.
4. Avoiding Redundancy or Circular References
   Object graphs in memory might have circular references or complex nesting. Flattening the structure avoids recursion and storage issues.
5. Storage Constraints
   Some datastores (like Firebase Realtime Database or Firestore) have size limits or structural expectations that influence data shape.

Question 8

Schema-less collections are good for _______________ data

Answer 8

semi-structured

Question 9

MongoDB’s speed is good for applications requiring _____________ data.

Answer 9

real-time

Question 10

Serve as the container for collections.

Answer 10

Databases

Question 11

Contain documents and are schema-less

Answer 11

Collections

Question 12

Units in MongoDB collections are JSON-like objects called ___________.

Answer 12

documents

Question 13

In MongoDB, new documents are automatically assigned a primary key called ________.

Answer 13

_id

Question 14

In version 3+ of MongoDB there is also a generated version key _____.

Answer 14

_v

Question 15

The _v of a document is incremented after the execution of certain functions such as ______ or ____________.

Answer 15

save or findOneAndUpdate

Question 16

Data relationships are supported using _______________ or _____________.

Answer 16

embedded documents or referenced documents

Question 17

MongoDB commands are centered around _________ which take the form of documents/JSON.

Answer 17

queries

Question 18

_________ documents keep related data together.

Answer 18

Embedded

Question 19

What is the advantage of embedded document?

Answer 19

Easier to query and update

Question 20

Disadvantage of embedded documents

Answer 20

Large embedded documents can impact read/write performance

Question 21

__________ documents take a normalized approach similar to Relational DBs.

Answer 21

Referenced

Question 22

Documents in other collections may reference them using an ___________.

Answer 22

Object ID or any identifying field

Question 23

Advantages of Referenced Documents

Answer 23

1. Multiple documents can refer to the same external document
2. Avoid the pitfalls of excessively large embedded documents.

Question 24

Disadvantage of Referenced Document

Answer 24

Require additional querying that many developers want to avoid

Question 25

Reason why MongoDB features high performance.

Answer 25

Embedded documents reduces need for joins and multi-document queries on the database

Question 26

Reason why MongoDB features high availability.

Answer 26

Supports replica sets

Question 27

Reason why MongoDB features scalability.

Answer 27

Supports sharding: distribution of data across several machines

Question 28

Before you can use data stored in databases, you have to ______________________.

Answer 28

convert it to a data structure your PL can understand

Question 29

The process of converting data between systems of incompatible data types, using object-oriented methods.

Answer 29

Object Relational Mapping

Question 30

The equivalent of ORM for NoSQL/Document-based databases.

Answer 30

Object Document Mapping

Question 31

Provided an object-oriented way to access and manipulate the data in our DBs.

Answer 31

ORMs/ODMs

Question 32

Mapping between some kinds of DBs comes with some _________.

Answer 32

data loss/overhead

Question 33

Advantages of ORM/ODM

Answer 33

1. In-dept knowledge of the DB is not required for application development 2. DB querying optimization is independent from business logic 3. Underlying DB technology can easily be changed

Question 34

One thing to make sure when using ORM

Answer 34

Use one that is being maintained

Question 35

Which one to use? NoSQL vs SQL

Answer 35

Use NoSQL when: data is semi-structured and big and needs fast and easy querying Use SQL when your data has strict-structure and involves relationships and does not need fast querying