Here is a schema for POP: JOURNALS(j_num, j_name, j_subject_area, chief_editor_r
ID: 3812029 • Letter: H
Question
Here is a schema for POP:
JOURNALS(j_num, j_name, j_subject_area, chief_editor_r_ssn[1])
chief_editor_rssn FK REF Researchers
ISSUES(j_num, i_num, i_date, i_num_pages)
j_num FK REF journals
RESEARCHERS(r_ssn, r_name, r_address, r_phone, r_institution)
ARTICLES(art_num, art_title, art_area_topic, art_abstract, A_submittedJ_j_num, A_publishedI_ j_num, ApublishedI_i_num)
A_submittedJ_j_num FK REF journals
(A_publishedI_ j_num, ApublishedI_i_num) FK REF issues
AREA_EDITS(j_num, r_ssn)
j_num FK REF journals
r_ssn FK REF researchers
WRITES(r_ssn, art_num)
r_ssn FK REF researchers
art_num FK REF articles
REVIEWS(r_ssn, art_num)
r_ssn FK REF researchers
art_num FK REF articles
RESEARCH_SPECIALTIES(r_spec_name)
RRS(r_ssn, r_spec_name)
r_ssn FK REF researchers
spec_name FK REF research_specialties
Please formulate the following queries using relational algebra:
1. The names of all researchers from University of Tulsa.
2. The names of all researchers from TU with an “MIS” specialty.
3. The names and addresses of all researchers who are chief editors.
4. The names of all journals with subject area = “MIS”.
5. The names and addresses of all researchers who have written or reviewed an article.
6. The titles of all articles published in “Journal of the Association of Information Systems”.
7. The number of pages of the issue that contains article number 5471.
8. The specialties of all researchers named “John Von Neumann” who are NOT at research institution “Princeton University”.
[1] The chief_editor_r_ssn is the r_ssn of the researcher who is chief editor for the journal.
Explanation / Answer
Answers:
1. Select r_name
From RESEARCHERS
where r_istitution="tulsa";
2. Select r_name
From RESEARCHERS
Where r_address="TU" AND r_spec_name="MIS";
3. Select r_name, r_address
From RESEARCHERS
where RESEARCHERS.r_SSN=
JOURNALS.chief_editor_SSN;
4. Select jname
from Journals
where artiles.art_area_topic="MIS";
5. Select r_name, r_address
From RESEARCHERS
where RESEARCHERS.R_SSN=WRITES.R_SSN
OR RESEARCHERS.R_SSN=REVIEWS.R_SSN;
6. Select art_title
From ARTICLES
where ARTICLES.APUBLISHEDI_i_num=
JOURNALS.j_num AND JOURNALS.jname="Journal
of the association of Information Systems";
7. Select i_num_pages
from issues
Where articles.art_num=5471;
8. Select r_spec_name
from RESEARCH_SPECIALITIES
where researchers.r_name="John Von Neumann" AND
NOT researchers.r_institution="Princeton University";
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