Which type of SQL is primarily responsible for database schema construction?

The type of SQL primarily responsible for database schema construction is Data Definition Language (DDL). DDL includes statements that allow users to create, alter, and drop database objects such as tables, indexes, and schemas. These operations define the architecture of the database and establish how data will be stored, structured, and accessed.

When you use DDL commands like CREATE TABLE, ALTER TABLE, or DROP TABLE, you are explicitly defining the schema of your database, which includes specifying the data types of each column, setting constraints, and establishing relationships among tables. This level of control is essential for setting up the foundational structure of a database, making DDL the correct answer in this context.

Other choices like Data Manipulation Language (DML) deal primarily with the manipulation of data within the already established schema, such as inserting, updating, or deleting records. The general term Structured Query Language (SQL) encompasses both DDL and DML, but does not specifically indicate schema construction. High-level Query Language (HQL) typically refers to languages that provide abstraction over data retrieval and manipulation; it is not a standard SQL type focused on schema definition.