Database Fundementals

Question 1

What are the basic functions of persistent storage in a database? (CRUD)

Answer 1

Create
Read
Update
Delete

Question 2

What is a flat file?

Answer 2

A simple way to store data for example a spreadsheet

Question 3

What are the advantages of a database over a flat file?

Answer 3

Concurrent usage
Scalability
Speed
Support for a variety of data types
Records and storage - CRUD

Question 4

What are structured databases?

Answer 4

Highly organized structures that store data in tables, with each table consisting of rows and columns

Question 5

What are semi-structured databases?

Answer 5

Even without rigid structure, they possess some level of organization by storing data in a way that allows for more flexibility

Question 6

What are unstructured databases?

Answer 6

▪ Designed to handle data without a predefined schema
▪ Word documents and PowerPoint presentations are great examples of
unstructured data

Question 7

Contrast relational and non-relational databases.

Answer 7

o Relational databases use a structured format with tables, rows, and columns

o Non-relational databases (NoSQL) do not rely on a standard table structure, and
they can handle structured, semi-structured, and unstructured data

Question 8

What does SQL stand for?

Answer 8

Structured Query Language

Question 9

What is a schema in a relational database?

Answer 9

A schema in a relational database is like a blueprint that defines how data is organized and how the relations among them are associated

Question 10

What is a primary and foreign key?

Answer 10

A primary key is a unique identifier for a record in a table (e.g. customer record in a customer database)

A foreign key is a field in a table that matches the key of another table and links them together (e.g. a customer order on orders page links to the customer record in database)

Question 11

Explain a key-value database

Answer 11

A non relational database that stores and retrieves data as a collection of key and value pairs.

A unique key and an associated value

Question 12

What are the uses and advantages of a key-value database?

Answer 12

Good for speed and efficiency where data is organized in flexible structures.

For example instagram -
key = user id
value = user account, posts etc.

Question 12

What is a document database?

Answer 12

In a document database, data is stored in self-describing, semi-structured documents

Documents can contain nested fields, arrays, and key-value pairs,
providing a more natural representation of complex data
structures

Question 13

What are the advantages of document databases?

Answer 13

• Document databases also provide excellent horizontal scalability and performance
• Document databases use embedded documents or references to represent relationships

Question 14

What is the primary Data Definition Language commands? (DDL)

Answer 14

Create - create a new table
Create Index - create an index on a table
Alter - modify an existing object
Drop - delete an entire table

Question 15

What are the primary Data Manipulation Language commands? (DML)

Answer 15

Insert - insert data
Select - retrieve data
Update - modify existing data
Delete - remove existing records

Question 16

Contrast DDL and DML

Answer 16

DDL provides the structure while DML handles the data within the structure.

Question 17

What is direct access?

Answer 17

Involves interacting with the database directly using a query language,
through the use of SQL typically for relational databases

Question 18

What is programmatic access?

Answer 18

Involves using a programming language or a database API to interact with
the database

Question 19

What is a query or report builder?

Answer 19

Tools that allow users to create queries and reports without writing SQL
code

Question 20

What is a database dump?

Answer 20

Methods of accessing data that involves creating a copy of the database
or its contents