Exam solution

Klausuren/Sda1/2018Winter/Solve/.gitignore

+.idea
 /target/
 /.settings/
 .classpath

Klausuren/Sda1/2018Winter/Solve/Schema/schema.sql

@@ -2,36 +2,46 @@ DROP TABLE IF EXISTS Para;
 DROP TABLE IF EXISTS Section;
 
 CREATE TABLE Section (
-  id CHAR(100) PRIMARY KEY
-  ,title TEXT
-  ,parent CHAR(100) REFERENCES Section
+  id CHAR(100)
+  ,PRIMARY KEY(id)
+  ,title TEXT NOT NULL
+  ,parent CHAR(100)
+  ,FOREIGN KEY (parent) REFERENCES Section(id)
   ,revisionFlag CHAR(7)
-  ,orderValue INT NOT NULL
+  ,CHECK(revisionFlag in ('new', 'changed', 'deleted'))
+  ,orderValue INT AUTO_INCREMENT UNIQUE
 );
 
 CREATE TABLE Para (
-   section CHAR(100) NOT NULL REFERENCES Section
+   section CHAR(100) NOT NULL
+  ,FOREIGN KEY (section) REFERENCES Section(id)
   ,para LONGTEXT
   ,revisionFlag CHAR(7)
-  ,orderValue INT NOT NULL
+  ,CHECK(revisionFlag in ('new', 'changed', 'deleted'))
+  ,orderValue INT AUTO_INCREMENT UNIQUE
 );
 
 
-INSERT INTO  Section VALUES ('categories', 'XML Document categories', NULL,       'new',  1);
-INSERT INTO  Section VALUES ('wellFormed', 'Well-formed documents',  'categories' ,NULL,  2);
+INSERT INTO  Section (id, title, parent, revisionFlag) VALUES ('categories', 'XML Document categories', NULL,        'new');
+INSERT INTO  Section (id, title, parent, revisionFlag) VALUES ('wellFormed', 'Well-formed documents',   'categories', NULL);
+INSERT INTO  Section (id, title, parent, revisionFlag) VALUES ('valid',      'Valid documents',         'categories', NULL);
+INSERT INTO  Section (id, title, parent, revisionFlag) VALUES ('api',        'Available APIs',          NULL,         'deleted');
 
-INSERT INTO  Para VALUES (
-  'categories', 'Documents belonging to this category do not adhere to any schema.','changed',  3);
 
+INSERT INTO  Para (section, para, revisionFlag) VALUES
+  ('categories', 'Documents belonging to this category do not adhere to any schema.','changed');
 
-INSERT INTO  Section VALUES ('valid', 'Valid documents',  'categories',          NULL,         4);
-INSERT INTO  Para VALUES ('valid', 'Valid documents require a schema.',          NULL,         5);
-INSERT INTO  Para VALUES ('valid', 'Common standards are DTD, XML Schema and Relax-NG.',NULL,  6);
+INSERT INTO  Para  (section, para, revisionFlag) VALUES
+  ('valid',      'Valid documents require a schema.',                                 NULL);
 
-INSERT INTO  Section VALUES ('api', 'Available APIs', NULL,                       'deleted',    7);
-INSERT INTO  Para VALUES    ('api', 'We introduce SAX and DOM here.',             NULL,    8);
-INSERT INTO  Para VALUES    ('api', 'Some APIs offer multiple language bindings.', NULL,   9);
+INSERT INTO  Para  (section, para, revisionFlag) VALUES
+  ('valid',      'Common standards are DTD, XML Schema and Relax-NG.',                NULL);
 
+INSERT INTO  Para (section, para, revisionFlag)  VALUES
+  ('api',        'We introduce SAX and DOM here.',                                    NULL);
+
+INSERT INTO  Para  (section, para, revisionFlag) VALUES
+  ('api',        'Some APIs offer multiple language bindings.',                       NULL);
 
 SELECT * FROM Section;
-SELECT * FROM Para;
+SELECT * FROM Para;
\ No newline at end of file

Klausuren/Sda1/2018Winter/Solve/src/main/java/de/hdm_stuttgart/mi/sda1/Book2Rdbms.java

@@ -10,18 +10,27 @@ import java.io.File;
 import java.io.IOException;
 import java.sql.Connection;
 import java.sql.DriverManager;
+import java.sql.PreparedStatement;
 import java.sql.SQLException;
 
-public class Book2Rdbms {
+public class Book2Rdbms implements AutoCloseable{
 
     private Connection conn;
 
+    private PreparedStatement insertSection, insertPara;
+
     private Document doc;
 
     public Book2Rdbms() {
         try {
             conn = DriverManager.getConnection(
                     "jdbc:mysql://localhost/hdm?serverTimezone=UTC", "hdmuser", "XYZ");
+            insertSection = conn.prepareStatement(
+                "INSERT INTO  Section (id, title, parent, revisionFlag) VALUES (?, ?, ?, ?);");
+
+            insertPara = conn.prepareStatement(
+                "INSERT INTO  Para (section, para, revisionFlag) VALUES (?, ?, ?)");
+
         } catch (SQLException e) {
             System.err.println("Unable to establish connection: " + e);
             System.exit(1);
@@ -46,19 +55,49 @@ public class Book2Rdbms {
 
         final XPathExpression<Element> xpathSearchPara =
                 XPathFactory.instance().compile(
-                        "//para" ,
+                        "/book/section" ,
                         new ElementFilter(),
                         null ,
                         Namespace.getNamespace(null));
 
-        System.out.println("Java stream:");
-        xpathSearchPara.evaluate(doc).stream().
-                map(Element::getText).forEach(System.out::println);
+        xpathSearchPara.evaluate(doc).forEach(this::handleSection);
+    }
+    private void handleSection(final Element section) { // Top level sections
+        handleSection(null, section);           // No parent.
+    }
 
-        System.out.println("\nSimple loop:");
-        for (final Element e: xpathSearchPara.evaluate(doc)) {
-            System.out.println(e.getText());
+    private void handleSection(final String parentId, final Element section) {
+        try {
+            insertSection.setString(1, section.getAttributeValue("id"));
+            insertSection.setString(2, section.getChildText("title"));
+            insertSection.setString(3, parentId);
+            insertSection.setString(4, section.getAttributeValue("revisionflag"));
+            insertSection.execute();
+
+            section.getChildren("section").forEach(            // recurse to child <section> elements
+                s -> handleSection(section.getAttributeValue("id") ,s));
+
+            section.getChildren("para").forEach( p -> {
+                    try {
+                        insertPara.setString(1, section.getAttributeValue("id"));
+                        insertPara.setString(2, p.getValue());
+                        insertPara.setString(3, p.getAttributeValue("revisionflag"));
+                        insertPara.execute();
+                    } catch (final SQLException e) {
+                        System.err.println("Unable to insert <para>: " + e);
+                        System.exit(1);
+                    }
+                }
+            );
+        } catch (final SQLException e) {
+            e.printStackTrace();
+            System.err.println("Unable to insert <section>: " + e);
+            System.exit(1);
         }
+    }
 
+    @Override
+    public void close() throws Exception {
+        conn.close();
     }
-}
+}
\ No newline at end of file