SQL (Structured Query Language) databases use primary and foreign keys to enable relationships between tables. A SQL database is a type of relational database that organizes data into tables that are related to each other by common fields or attributes. A primary key is a field or attribute that uniquely identifies each record in a table. A foreign key is a field or attribute that refers to the primary key of another table. Primary and foreign keys enable relationships between tables by establishing links or associations between records that share common values. Rows, fields, and schemas are not concepts that are enabled by primary and foreign keys in SQL databases. A row is a horizontal arrangement of fields or attributes that store information about a specific record or entity in a table. A field is a vertical arrangement of fields or attributes that store the same type of information for different records in a table. A schema is a structure or design that defines how data is organized and stored in a database. References: CompTIA IT Fundamentals+ Study Guide: Exam FC0-U61, Second Edition, Chapter 5: Database Fundamentals, page 194.