Relational database theory, transactions, ACID properties, and query processing concepts from an intro database systems course.
40 cards · basic cards · AI-written, checked twice. Edit anything.
- What is a relational database?
- A database organized as a collection of tables (relations) with rows (tuples) and columns (attributes), where data is structured to minimize redundancy.
- In relational databases, what is a tuple?
- A single row in a table, representing one instance of the entity being described.
- In relational databases, what is a relation?
- A table consisting of rows (tuples) and columns (attributes), the fundamental data structure in a relational database.
- What is a primary key?
- A column or set of columns that uniquely identifies each row in a table.
- What is a foreign key?
- A column or set of columns in one table that references the primary key of another table, establishing a relationship between tables.
- What does ACID stand for?
- Atomicity, Consistency, Isolation, Durability - the four key properties of database transactions.
- What is atomicity in the context of database transactions?
- A transaction is treated as a single, indivisible unit of work; it either completes fully or rolls back completely.
- What is consistency in the context of database transactions?
- A transaction brings the database from one valid state to another valid state, maintaining all defined rules and constraints.
- What is isolation in the context of database transactions?
- Concurrent transactions do not interfere with each other; the effects of one transaction are not visible to others until it commits.
- What is durability in the context of database transactions?
- Once a transaction commits, its changes are permanently stored and survive any failures, including power loss or system crashes.
- What is a database transaction?
- A sequence of database operations treated as a single logical unit that must either complete entirely or not execute at all.
- What is normalization in database design?
- A process of organizing data to reduce redundancy and improve data integrity by dividing tables and defining relationships between them.
- What is First Normal Form (1NF)?
- A relation is in 1NF if all attributes contain only atomic (indivisible) values; no repeating groups or array-type attributes are allowed.
- What is Second Normal Form (2NF)?
- A relation is in 2NF if it is in 1NF and all non-key attributes are fully functionally dependent on the entire primary key.
- What is Third Normal Form (3NF)?
- A relation is in 3NF if it is in 2NF and no non-key attribute is transitively dependent on the primary key.