Database Management Systems Flashcards

Which type of JOIN returns only the rows where there is a match in both tables?

Answer: INNER JOIN

An INNER JOIN returns only the rows that have matching values in both tables being joined.

What is the purpose of database normalization?

Answer: To reduce data redundancy and improve data integrity

Database normalization organizes tables to reduce data redundancy and improve data integrity by eliminating anomalies in insertion, update, and deletion operations.

A Database Management System (DBMS) provides all of the following EXCEPT:

Answer: Network packet routing

Network packet routing is a function of network hardware and software, not a DBMS, which handles storage, retrieval, access control, and recovery.

Which database language is used to define the structure of database objects like tables and indexes?

Answer: Data Definition Language (DDL)

Data Definition Language (DDL) includes commands like CREATE, ALTER, and DROP that define and modify the structure of database objects.

In an Entity-Relationship (ER) diagram, a 'weak entity' is one that:

Answer: Cannot exist without depending on another entity

A weak entity cannot be uniquely identified by its own attributes alone and depends on a parent (strong) entity for its existence and identification.

Which of the following best describes a NoSQL database?

Answer: A non-relational database designed for flexible, scalable storage of unstructured or semi-structured data

NoSQL databases are non-relational systems designed to handle flexible data models (document, key-value, column-family, graph) and horizontal scaling for large datasets.

What is a 'deadlock' in the context of database concurrency?

Answer: A state where two or more transactions are each waiting for the other to release a resource, causing a standstill

A deadlock occurs when two or more transactions permanently block each other by each holding a resource the other needs, preventing any of them from completing.