Final answer:
The correct answer is 'd: join', which is used in SQL to combine rows from multiple tables based on a related column and allows expressing a relationship between multiple tables.
Step-by-step explanation:
The option that allows you to express a relationship between one or more tables in a database query is d: join. A join is used to combine rows from two or more tables, based on a related column between them. It's a powerful SQL operation that lets you query multiple tables simultaneously and retrieve data that exists across these tables. Moreover, using joins can facilitate complex database queries and enhance the database's flexibility in data retrieval tasks.
The answer to the question is join.
In database management systems, the join operation allows you to combine rows from two or more tables based on a related column between them.
For example, if you have a table of students and a table of courses, you can use a join operation to find all the students who are enrolled in a specific course by linking the tables based on the common course ID. This allows you to express a relationship between the two tables and retrieve relevant data.