public void changeTitle(int cid, String newtitle) {
try {
String cmd = "update COURSE set Title = ? where CId = ?";
PreparedStatement pstmt = conn.prepareStatement(cmd);
pstmt.setString(1, newtitle);
pstmt.setInt(1, cid);
pstmt.executeUpdate();
} catch (SQLException e) {
dbm.cleanup();
throw new RuntimeException("error changing title", e);
}
}
public Course insert(int cid, String title, Dept dept) {
try {
// make sure that the cid is currently unused
if (find(cid) != null) return null;
String cmd = "insert into COURSE(CId, Title, DeptId) " + "values(?, ?, ?, ?)";
PreparedStatement pstmt = conn.prepareStatement(cmd);
pstmt.setInt(1, cid);
pstmt.setString(2, title);
pstmt.setInt(3, dept.getId());
pstmt.executeUpdate();
return new Course(this, cid, title, dept);
} catch (SQLException e) {
dbm.cleanup();
throw new RuntimeException("error inserting new course", e);
}
}
public Collection<Section> getSections(int cid) {
try {
Collection<Section> sections = new ArrayList<Section>();
String qry = "select SectId from SECTION where CourseId = ?";
PreparedStatement pstmt = conn.prepareStatement(qry);
pstmt.setInt(1, cid);
ResultSet rs = pstmt.executeQuery();
while (rs.next()) {
int sectid = rs.getInt("SectId");
sections.add(dbm.findSection(sectid));
}
rs.close();
return sections;
} catch (SQLException e) {
dbm.cleanup();
throw new RuntimeException("error getting course sections", e);
}
}
public Course find(int cid) {
try {
String qry = "select Title, DeptId from COURSE where CId = ?";
PreparedStatement pstmt = conn.prepareStatement(qry);
pstmt.setInt(1, cid);
ResultSet rs = pstmt.executeQuery();
// return null if course doesn't exist
if (!rs.next()) return null;
String title = rs.getString("Title");
int deptid = rs.getInt("DeptId");
rs.close();
Dept dept = dbm.findDept(deptid);
return new Course(this, cid, title, dept);
} catch (SQLException e) {
dbm.cleanup();
throw new RuntimeException("error finding course", e);
}
}
