Database Concepts & Terminology Flashcards

What does DDL stand for in the context of SQL?

Answer: Data Definition Language

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

Which SQL sublanguage includes the INSERT, UPDATE, and DELETE statements?

Answer: DML

DML (Data Manipulation Language) consists of statements that add, modify, or remove data rows within existing database tables.

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

Answer: Cannot be uniquely identified without the primary key of another entity

A weak entity lacks a primary key of its own and depends on a related strong entity's primary key (called the owner entity) for its unique identification.

What is the purpose of an index in a relational database?

Answer: To speed up data retrieval operations on a table

An index is a data structure that provides a fast lookup path to rows in a table, significantly improving query performance at the cost of additional storage and write overhead.

Which concept refers to hiding the internal complexity of a database from end users and applications?

Answer: Abstraction

Data abstraction allows users and applications to interact with data at a high level without needing to know how it is physically stored or organized internally.

A 'composite key' is a primary key that:

Answer: Consists of two or more columns combined to uniquely identify a row

A composite key uses a combination of two or more columns whose combined values are unique across all rows, used when no single column alone can serve as the primary key.

What is a 'stored procedure' in a database?

Answer: A precompiled set of SQL statements stored in the database that can be called by name

A stored procedure is a named, precompiled collection of SQL statements saved in the database that can be executed with a single CALL or EXECUTE command.