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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
putangina
