Data, Databases & Big Data EZ

A set of flashcards covering lecture material on data management, DBMS, Big Data characteristics, Data Warehousing, and Knowledge Management Systems.

Why is managing data considered difficult for modern businesses?

Data management is difficult because data grows very fast, comes from many sources (internal, customers, internet), includes new types like blogs and sensors, can degrade over time, and must comply with government rules like GDPR.

What is clickstream data?

Clickstream data refers to the record of what users do on websites.

What is Data Governance?

Data Governance is the management of data across an entire company, including rules, policies, security, storage, and usage to ensure data is handled properly.

What is the goal of Master Data?

The goal of Master Data is to create one correct version of core data, such as customers, products, and employees, providing a "one version of truth."

According to the lecture, what is the hierarchy of data from smallest to largest units?

$$\text{Bit} \rightarrow \text{Byte} \rightarrow \text{Field} \rightarrow \text{Record} \rightarrow \text{File} \rightarrow \text{Database}$$

What is a Database Management System (DBMS)?

A DBMS is software that manages databases by solving problems like data redundancy, data isolation, and data inconsistency while improving security, integrity, and independence.

In the relational database model, what are rows and columns called?

Rows are called records and columns are called attributes.

What is the difference between a Primary Key and a Foreign Key?

A Primary Key is a unique ID for each row in a table, whereas a Foreign Key is a field that links two tables together.

What are the characteristics of Big Data known as the "3 V’s"?

$\text{Volume (huge size)}$, $\text{Velocity (arrives very fast)}$, and $\text{Variety (different types of data)}$.

What tools are used to manage and process Big Data?

Tools include NoSQL databases (for flexible data), Hadoop (a processing system), and MapReduce (for processing large data sets).

What is the difference between a Data Warehouse and a Data Mart?

A Data Warehouse is a large storage system for historical company data used for strategic decision-making, while a Data Mart is a smaller, cheaper version designed for a specific department (e.g., Marketing).

What are the four key characteristics of a Data Warehouse?

1. Integrated (combines many systems); 2. Time Variant (stores historical data); 3. Non-Volatile (stable/not changed); 4. Multidimensional (analysis from different perspectives).

What does the acronym ETL represent in the data integration process?

$\text{Extract (take data from systems)}$, $\text{Transform (clean and organise data)}$, and $\text{Load (move data into the warehouse)}$.

What is OLAP and how is it used?

OLAP stands for Online Analytical Processing; it allows businesses to analyse trends, compare information, and create reports quickly using a multidimensional data cube.

What is the difference between Explicit Knowledge and Tacit Knowledge?

Explicit Knowledge is easy to record and share (e.g., manuals, reports), while Tacit Knowledge is personal experience and skills that are harder to record (e.g., leadership, problem-solving).

What are the six steps in the Knowledge Management System (KMS) cycle?

$\text{1. Create}$, $\text{2. Capture}$, $\text{3. Refine}$, $\text{4. Store}$, $\text{5. Manage}$, and $\text{6. Disseminate}$.

What is SQL and what is its purpose?

SQL (Structured Query Language) is used to search, update, and manage data within a database.

In an Entity Relationship Diagram (ERD), what are the three types of relationships based on cardinality?

$\text{One-to-One (1:1)}$, $\text{One-to-Many (1:M)}$, and $\text{Many-to-Many (M:M)}$.