The Gradiance service for Database Systems comes with a collection of root questions and lab projects. In addition, the root questions are packaged into homework sets on the various topics normally covered in a first or second course on Database Systems. The instructor is able to use these materials in a variety of ways:
- Select which homework sets and lab projects to use, and set the open date and due date for each.
- Select homework sets as in Option (1), and customize them for the class by deleting or adding questions.
- Create new homework sets from the available question bank.
- Create new questions, and use them in homework sets.
For the area of Database Systems, Gradiance offers a collection of homework sets using a special technique called root questions. In a root question, the student is given a problem to work out, and their knowledge is sampled by randomly chosen multiple-choice questions. As with labs, students are encouraged to try an assignment, consisting of several root questions, until they get them all correct. Each time they give a wrong answer to a question, they immediately receive a choice explanation, a bit of advice that either explains why that answer is wrong, gives a hint, or suggests the general approach to the problem.
Advantage: Because the assignments are in the form of multiple-choice questions, the grading is automatic, and solutions are made available as soon as the assignment is completed. However, because students are given randomly selected answer choices each time they try a problem, they are encouraged to solve the complete underlying problem, and are given hints until they can do so. Thus, students get the benefit of long-answer problems graded by the course staff, without the staff having to wade through a pile of papers.
Another component of Gradiance services for Database Systems is a set of predesigned SQL lab projects, using mySQL as the database engine. After a lab project is assigned by the instructor, students are given a description of a database schema and asked to write certain queries. Student answers are checked against a secret evaluation database, and, if their query produces the wrong answer, given an explanation in terms of a separate example database: what their query did, and what it should have done on this database. Students are encouraged to revise their queries until all are correct.
Advantage: In conventional assignments, students write programs that the grader has to evaluate. In many cases, graders can only guess what the program would do. With Gradiance, the program has to be right, or the student is asked to try again. Moreover, the student gets critical help to guide them in reaching a working program, rather than simply being given a sample answer at the end of the assignment, which may or may not bear any resemblance to the approach they chose.