What is the name of the descriptive language used to create and define entities and relationships in a database?

The correct answer is the Data Definition Language (DDL) because DDL is specifically designed to define and create database structures. This includes defining entities such as tables, views, indexes, and relationships among them. Using DDL commands, database designers can create the framework of the database by specifying the schema. For example, commands like CREATE TABLE, ALTER TABLE, and DROP TABLE are part of DDL and are crucial for setting up the database architecture that dictates how data will be stored and accessed.

In contrast, Data Control Language (DCL) is focused on the control over access to data, dealing with permissions and security. Data Manipulation Language (DML) is aimed at the manipulation of data that already exists in the database, allowing for operations like inserting, updating, and deleting data. Structured Query Language (SQL) is a broader term that encompasses both DDL and DML among other functionalities. While SQL includes commands for defining structures, it is DDL specifically that delineates the process of creating and defining those structures independently.