L.01 Flashcards
Introduction to Databases
What is the difference between data, information, and knowledge?
Data: Raw data without meaning (e.g., stored signals). May or may not be redundant or correct.
Information: Data with labels or descriptions, usually structured (e.g., database schema). Generally assumed to be not redundant nor wrong.
Knowledge: Information with context and meaning, beyond what programs typically process.
Give me types of databases.
-Files & File Systems
-Spreadsheets
-SQL Databases
-NoSQL Databases
What does CRUD stand for in databases?
CRUD stands for:
-Create (Insert new data)
-Read (Retrieve data)
-Update (Modify existing data)
-Delete (Remove data)
What is a database?
A database is:
A collection of related data
Represents some aspect of the real world
Logically coherent with inherent meaning
Built for a specific purpose
What is an example of a university database structure?
A University Database may contain:
STUDENT (student info)
COURSE (course details)
SECTION (course sections)
GRADE_REPORT (student grades)
PREREQUISITE (course dependencies)
What is metadata? Give an example
Metadata is “data about data.”
It describes what actual data should look like.
Example: Java classes define object instances.
What are some advantages of using a DBMS?
-Persistent storage for program objects
-Efficient querying (indexing, optimization, caching)
-Controlling redundancy (normalization)
-Ensuring data integrity (data types, uniqueness, referential integrity)
-Transactional properties (ACID)
What are the ACID properties of transactions?
1) Atomicity – All changes are applied, or none at all.
2) Consistency – The database is always in a consistent state.
3) Isolation – Concurrency control, guarantees that concurrent transactions do not interfere.
4) Durability – Once a change is applied, it remains even through failures.
What is querying in databases? Give example
A special form of “read” operation. Used to retrieve multiple entries or specific parts of data based on constraints.
Example:
*SELECT last_name FROM students WHERE course_id = ‘DIT034’.
Give me all files that end with “exe”.
*Give me the last names of all students enrolled in DIT034.
What are common DBMS interaction methods?
-Menu-based interfaces (Web browsing)
-Forms-based interfaces
-Graphical User Interfaces (GUI)
-Natural language interfaces
-Speech input/output
-Interfaces for parametric users
-APIs (e.g., Java database interaction)
What is the Client/Server architecture in databases?
-The Database Server stores and manages the database.
-Clients (programs, applications) send queries and receive results.
What is the Three-Schema Architecture?
External Schema – User views
Conceptual Schema – Logical structure of data
Internal Schema – Physical storage
