Second data source: university 2

We now consider the database of another university. It has a different schema, composed of three tables:

uni2.person

The table uni2.person describes the students and the academic staff of the university.

pid	fname	lname	status
1	Zak	Lane	8
2	Mattie	Moses	1
3	Céline	Mendez	2

The column status is populated with magic numbers (they differ from the ones of the first university):

• 1 -> Undergraduate Student
• 2 -> Graduate Student
• 3 -> PostDoc
• 7 -> Full Professor
• 8 -> Associate Professor
• 9 -> Assistant Professor

As you can see, undergraduate and graduate students are now distinguished.

uni2.course

The table uni2.course contains information about courses, their topic, their lecturer and their lab teacher.

cid	lecturer	lab_teacher	topic
1	1	3	Information security

cid is a primary key. Note that in this data source, there are at most two teachers per course. Lecturers and lab teachers are now distinguished.

uni2.registration

The table uni2.registration contains the n-n relation between courses and attendees.

pid	cid
2	1

There is no primary key, but two foreign keys to the tables uni2.course and uni2.person.

New mappings

Let us add the following mapping assertions together with the previous one.

Mapping uni2.person

• Target:

:uni2/person/{pid} a foaf:Person ;
    foaf:firstName {fname}^^xsd:string ;
    foaf:lastName {lname}^^xsd:string .

• Source:

SELECT *
FROM "uni2"."person"

Mapping uni2-course

• Target:

:uni2/course/{cid} a :Course ;
    :title {topic}^^xsd:string ;
    :isGivenAt :uni2/university .

• Source:

SELECT *
FROM "uni2"."course"

Mapping uni2-lecturer

• Target:

:uni2/person/{lecturer} :givesLecture :uni2/course/{cid} .

• Source:

SELECT *
FROM "uni2"."course"

Mapping uni2-lab-teacher

• Target:

:uni2/person/{lab_teacher} :givesLab :uni2/course/{cid} .

• Source:

SELECT *
FROM "uni2"."course"

Mapping uni2-registration

• Target:

:uni2/person/{pid} :attends :uni2/course/{cid} .

• Source:

SELECT *
FROM "uni2"."registration"

Mapping uni2-undergraduate

• Target:

:uni2/person/{pid} a :UndergraduateStudent .

• Source:

SELECT *
FROM "uni2"."person"
WHERE "status" = 1

And so on for the graduate students, postdocs, full professors, associate professors and assistant professors.

SPARQL

We can now run the previous SPARQL queries and observe that the results combine entries from the two datasets.