Data Schemas

Kahoot

What does term “data schema” refer to?

An abstract design representing data storagge

Why is it important for a data analyst to understand data schemas?

Helps them interact with existing data-bases

What are two main types of databases

Relational and non-relational databases

Main goal of data normalization

Remove redundant data and redundancies

Three types of data base relationships

One-to-many, many-to-one, many-to-many

What ensures data integrity using primary and foreign keys?

Referential integrity

What is a key characteristic of a relational database?

Data is stored in tables linked by relationships

What does RDBMS stand for?

Relational Database Management System

Which of the following is an example of an RDBMS?

MySQL

How are tables in a relational database connected?

By matching fields in different tables

SQL stand for?

Structured Query Language

What is SQL used for?

Querying and managing relational databases

What is the main purpose of a common field in relational databases?

to link tables together

What is a key characteristic of a non-relational database?

It is designed for big data and scalability

Which of the following is NOT a type of non-relational database?

Hierarchical Database

Which of the following is NOT a type of non-relational database?

It quickly retrieves values based on a unique key

What type of data format is commonly used in document-oriented databases?

JSON or XML

Which of the following is a major advantage of non-relational databases?

They offer flexibility in data storage and scalability

How do non-relational databases differ from relational databases?

They allow storing both structured and un-structured data

Main goal of data normalization

To eliminate redundant data and improve efficiency

What does the First Normal Form (INF) focus on?

Eliminating redundant data by using dedicated tables

How does the Second Normal Form (2NF) improve database design?

It ensures related data is moved into separate tables

What is the primary focus of Third Normal Form (3NF)?

Eliminating fields that do not depend on the primary key

Why is it important to use foreign keys in normalization?

To establish connections between related data in different tables

What is a primary key in a database?

A unique identifier for a record in a table

What is the role of a foreign key in a database?

It is a primary key in another table used to create relationships

Example of one-to-one relationship?

Student and their enrolment form

One-to-many relationship database?

One record in a table is associated with multiple records in another table

scenario best represent many-to-many relationship?

Student enrolling in multiple courses and course enrolling multiple students

Primary purpose of referential integrity in a database?

Ensure foreign keys remain valid primary keys

What happens when referential integrity is missing?

Data records may become orphaned or inconsistent

What is the function of a cascade update in referential integrity?

It updates primary key values in related tables automatically

Purpose of a cascade delete?

It removes all related records when a primary key is deleted

How can referential integrity help maintain data quality?

By ensuring all data modifications follow defined relationships

What is data denormalization

adds redundant data to a normalized database to improve query performance

Why might a data analyst use denormalized data?

To make data retrieval and analysis more readable

Which of the following is a key characteristic of denormalized data?

It contains repetitive and redundant data

How does data denormalization benefit big data analysis?

It allows for easier data visualization and reportingD

Dami

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