# 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:
ex: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:
ex:uni2/course/{cid} a :Course ;
    :title {topic}^^xsd:string ;
    :isGivenAt ex:uni2/university .
  • Source:
SELECT *
FROM "uni2"."course"

# Mapping uni2-lecturer

  • Target:
ex:uni2/person/{lecturer} :givesLecture ex:uni2/course/{cid} .
  • Source:
SELECT *
FROM "uni2"."course"

# Mapping uni2-lab-teacher

  • Target:
ex:uni2/person/{lab_teacher} :givesLab ex:uni2/course/{cid} .
  • Source:
SELECT *
FROM "uni2"."course"

# Mapping uni2-registration

  • Target:
ex:uni2/person/{pid} :attends ex:uni2/course/{cid} .
  • Source:
SELECT *
FROM "uni2"."registration"

# Mapping uni2-undergraduate

  • Target:
ex:uni2/person/{pid} a :UndergraduateStudent .
  • Source:
SELECT *
FROM "uni2"."person"
WHERE "status" = 1

And so on for the graduate students, postdoc, 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.