Final answer:
The student is referring to a 'JOIN' clause in SQL, which is used to combine rows from two tables based on a related column. This is a common operation in relational database management, specifically when retrieving related information from multiple tables where the values of a specified field are equal.
Step-by-step explanation:
The student is asking about a concept in database management, specifically SQL (Structured Query Language), which is used to manage and manipulate relational databases. The blank in the question can be filled with 'JOIN' clause, which is a part of SQL. When you have two tables and you want to retrieve information that is present in both, you use a JOIN clause to combine rows from these tables based on a related column between them.
A common syntax for this operation would be:
SELECT * FROM tableA JOIN tableB ON tableA.field1 = tableB.field1;
This SQL statement retrieves data from both tableA and tableB where the values of field1 are matching in both tables.