From 3c5a09ef620a9256fb3cf85d5d913fc2507515b0 Mon Sep 17 00:00:00 2001
From: Santo Cariotti <santo@dcariotti.me>
Date: Sat, 6 Feb 2021 20:35:22 +0100
Subject: course: databases

---
 Year_2/Databases/README.md               |  4 +++
 Year_2/Databases/university_marks.dtd    | 14 +++++++++++
 Year_2/Databases/university_marks.xml    | 43 ++++++++++++++++++++++++++++++++
 Year_2/Databases/university_marks.xquery | 11 ++++++++
 4 files changed, 72 insertions(+)
 create mode 100644 Year_2/Databases/README.md
 create mode 100644 Year_2/Databases/university_marks.dtd
 create mode 100644 Year_2/Databases/university_marks.xml
 create mode 100644 Year_2/Databases/university_marks.xquery

diff --git a/Year_2/Databases/README.md b/Year_2/Databases/README.md
new file mode 100644
index 0000000..5af8687
--- /dev/null
+++ b/Year_2/Databases/README.md
@@ -0,0 +1,4 @@
+# XQuery
+XQuery files are compiled by xqilla.
+
+[debian](https://packages.debian.org/bullseye/xqilla) | [ubuntu](https://packages.ubuntu.com/focal/xqilla)
diff --git a/Year_2/Databases/university_marks.dtd b/Year_2/Databases/university_marks.dtd
new file mode 100644
index 0000000..caab080
--- /dev/null
+++ b/Year_2/Databases/university_marks.dtd
@@ -0,0 +1,14 @@
+<!ELEMENT libretti (libretto)*>
+<!ELEMENT libretto (studente, esami)?>
+<!ELEMENT studente (nome, cognome)>
+<!ELEMENT nome (#PCDATA)>
+<!ELEMENT cognome (#PCDATA)>
+<!ATTLIST studente
+    cdl CDATA #REQUIRED
+    matricola CDATA #REQUIRED
+>
+<!ELEMENT esami (esame)+>
+<!ELEMENT esame (materia, data, voto)>
+<!ELEMENT materia (#PCDATA)>
+<!ELEMENT data (#PCDATA)>
+<!ELEMENT voto (#PCDATA)>
diff --git a/Year_2/Databases/university_marks.xml b/Year_2/Databases/university_marks.xml
new file mode 100644
index 0000000..fcd0eb5
--- /dev/null
+++ b/Year_2/Databases/university_marks.xml
@@ -0,0 +1,43 @@
+<?xml version="1.0" ?>
+<!DOCTYPE libretti SYSTEM "university_marks.dtd">
+<libretti>
+    <libretto>
+        <studente cdl="Computer engineering" matricola="0000122">
+            <nome>Luke</nome>
+            <cognome>Don</cognome>
+        </studente>
+        <esami>
+            <esame>
+                <materia>Algebra</materia>
+                <data>2021-02-02</data>
+                <voto>30</voto>
+            </esame>
+        </esami>
+    </libretto>
+    <libretto>
+        <studente cdl="Computer science" matricola="0000123">
+            <nome>John</nome>
+            <cognome>Doe</cognome>
+        </studente>
+        <esami>
+            <esame>
+                <materia>Databases</materia>
+                <data>2021-02-06</data>
+                <voto>18</voto>
+            </esame>
+        </esami>
+    </libretto>
+    <libretto>
+        <studente cdl="Computer science" matricola="0000125">
+            <nome>Mark</nome>
+            <cognome>Zuck</cognome>
+        </studente>
+        <esami>
+            <esame>
+                <materia>Databases</materia>
+                <data>2021-02-06</data>
+                <voto>30</voto>
+            </esame>
+        </esami>
+    </libretto>
+</libretti>
diff --git a/Year_2/Databases/university_marks.xquery b/Year_2/Databases/university_marks.xquery
new file mode 100644
index 0000000..e2f0e4e
--- /dev/null
+++ b/Year_2/Databases/university_marks.xquery
@@ -0,0 +1,11 @@
+<students>
+{
+for $student in doc("university_marks.xml")//libretto
+where $student/esami//voto/text()=30
+return <student>
+    {$student/studente/nome/text()}
+    { ' ' }
+    {$student/studente/cognome/text()}
+    </student>
+}
+</students>
-- 
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