Download presentation
Presentation is loading. Please wait.
Published byΚόρη Λιάπης Modified over 6 years ago
1
Creating Databases SELECT. UPDATE. Demonstrate projects. Do not track.
Classwork / Homework: Prepare to choose teams & projects.
2
Warning Changes in php from last time.
THIS IS INEVITABLE and is mainly a good thing. I think I made required changes, but only did modest testing. AND I did all the testing. Always involve other people to do testing!
3
SELECT … what if you want only DISTINCT values?
For example, the trivia quiz starts with a form to choose the category. People (site administrators) adding questions can put in any category.
4
from php code choosecategory.php
<h1> Welcome to the Quiz </h1> <br> <h3> Sign in and select a category for your question </h3> <form action="askquestion.php" method=post> <p>Name <input type=text name='player' size=30 <?php … $query="SELECT DISTINCT category FROM questions"; $categories = mysqli_query($link,$query); while ($row=mysqli_fetch_array($categories)) { $cat=$row['category']; print ("<option value='$cat'>$cat</option><br>\n"); }
5
SQL join SELECT statement against a table made up by JOINing tables together on identical fields. Different types of JOIN: JOIN (same as INNER JOIN) LEFT JOIN RIGHT JOIN FULL JOIN 5
6
LEFT, RIGHT, FULL JOINs These provide ways to pick up missing records.
CHECK OUT THE w3schools and other tutorials! Will show example from the quiz show Task: find questions that player has NOT answered correctly and has NOT been asked that day.
7
Two steps Create a temporary table of all the questions asked a particular player and answered correctly OR asked today. need to specify the contents of the table. In this case, one field of INT datatype If there have been past questions, do a SELECT using LEFT JOIN to extract any question NOT present in the past array. Otherwise, do a simple SELECT
8
$query="CREATE temporary TABLE past (item_id INT)";
1st step: create temporary table, past $query="CREATE temporary TABLE past (item_id INT)"; $query.= " SELECT question_id FROM history WHERE (player_id='".$player_id; $query.= "' AND (whenplayed='".$today."' OR correct))"; $result=mysqli_query($link,$query); $query="SELECT * FROM past"; $result = mysqli_query($link,$query); $Num_past = mysqli_num_rows($result);
9
2nd step if ($Num_past>0) {
$sel = "SELECT questions.question_id, question, answerpattern, value from questions"; $sel =$sel . " LEFT JOIN past ON questions.question_id = past.question_id WHERE "; $sel = $sel . " category='" . $pickedcategory . "' AND past.question_id IS NULL"; } else { $sel="SELECT question_id, question, answerpattern, value from questions "; $sel= $sel . " WHERE category= '" . $pickedcategory. "'";
10
SELECT Conditions WHERE with a JOIN After aggregating using GROUP
Sets condition on individual records with a JOIN the ON specifying what field to do the JOIN on, generally a foreign key equal to a primary key After aggregating using GROUP HAVING sets a condition on grouped data 10
11
Conditions Remember: the single equal sign is the operator for equality! Other comparisons: >, <, >=, <= LOGIC: AND, OR, NOT REGEX for regular expressions LIKE: another way to specify a pattern
12
Conditions Can select using set of values
SELECT * FROM questions WHERE category IN (‘trivia’,’misc’,’silly’) See also BETWEEN
13
Recall 4 tables In most cases, people have only 1 role.
Affleck is an exception. In most cases, awards are for 1 role. Producing is an exception. Some roles are not nominated for anything, hence the 0. 4 tables movies mid mname mdate people pid pname … nominations aid rid category win … roles rid mid pid role (director,actor,etc.)
14
Tasks List all movies by name, ordered by date
SELECT mname, mdate FROM movies ORDER BY mdate List all people by name with roles in a given movie, named $moviename (this is mixture of php and straight SQL) SELECT p.pname,m.mname,r.role FROM movies as m JOIN roles as r ON m.mid = r.mid JOIN people as p ON p.pid = r.rid WHERE m.mname='$moviename'
15
next task: reuse JOIN clauses
List all directors (by name), with movie (by name) ordered by movie name SELECT p.pname,m.mname FROM movies as m JOIN roles as r ON m.mid = r.mid JOIN people as p ON p.pid = r.rid WHERE r.role='Director' ORDER BY m.mname
16
List all movies by name in which someone was nominated for Best Lead Actor
SELECT m.mname FROM movies as m JOIN roles as r ON m.mid = r.mid JOIN people as p ON p.pid = r.rid JOIN nominations as n ON n.rid=r.rid WHERE n.award='Best Lead Actor'
17
next task, again reuse JOIN clauses plus start of WHERE
List all movies by name in which someone was nominated for an acting category. Count number. Best Lead Actor, Best Lead Actress, Best Supporting Actor, Best Supporting Actress SELECT m.mname, count(*) FROM movies as m JOIN roles as r ON m.mid = r.mid JOIN people as p ON p.pid = r.rid JOIN nominations as n ON n.rid=r.rid WHERE n.award IN ('Best Lead Actor, Best Lead Actress, Best Supporting Actor, Best Supporting Actress) ORDER BY m.mname GROUP BY m.mname
18
More List movie name, person name, nominated award ordered by movie name SELECT m.mname, p.pname, n.award FROM movies as m JOIN roles as r ON m.mid = r.mid JOIN people as p ON p.pid = r.rid JOIN nominations as n ON n.rid=r.rid ORDER BY m.mname
19
Next List winners: movie name, person name, award
SELECT m.mname, p.pname, n.award FROM movies as m JOIN roles as r ON m.mid = r.mid JOIN people as p ON p.pid = r.rid JOIN nominations as n ON n.rid=r.rid ORDER BY m.mname WHERE n.win='true'
20
List movie name, number of people nominated, ordered from high to low
SELECT m.mname, count(*) FROM movies as m JOIN roles as r ON m.mid = r.mid JOIN people as p ON p.pid = r.rid JOIN nominations as n ON n.rid=r.rid ORDER BY m.mname GROUP BY m.mname EXTRA CREDIT: figure out how not to count multiples for awards that have multiples (such as producer, technical awards)
21
Research Some questions require consideration of absent records
What movies were nominated (had people nominated) for Best Movie but not Best Director ? Look up and study examples of LEFT JOINS
22
UPDATE Can update a single record or a set of records.
UPDATE questions SET text = ‘$ntext’ WHERE ques_id=‘$qid’ Assumes table names questions with fields text and ques_id and php variables $ntext and $qid set previously
23
UPDATE Raise all the prices 10%
UPDATE products SET price=1.10*price Raise the prices that are over 100 by 5% UPDATE products SET price=1.05*price WHERE price > 100
24
Projects Recall Geolocation / Google maps . Quizhttp://faculty.purchase.edu/jeanine.meyer/html5/mapmediaquiz.html Does not use database. Enhancement is to add database for locations
25
Projects Bookmarks, with password system for finders
26
Projects Student departments
27
Projects Trivia quiz edit feature? change scoring? improve interface?
28
Projects Origami store need file upload to upload pictures general improvement scale up
29
Projects Songs and features in songs. Find similar songs
30
Stories
31
Citations
32
Assignment Team project to present and Enhance one of these projects
There will be an assignment to build database project totally on your own
33
Projects Late addition: citations (may need updating) student database
trivia quiz book marks origami store songs Stories Google maps media portal (or quiz) Note: this does NOT have a database at all! So obvious enhancement is to make use of database, possibly with table for player or ??? Late addition: citations (may need updating)
34
Preview (after midterm)
Self assign or I assign teams (3-4) Teams will pick projects resolve conflicts
35
Assignment https://donottrack-doc.com/en/
This is a set of short interactive videos concerning tracking. Allow yourself a few days. Make a response. You may consider including a screen shot on your results.
36
Homework [Prepare to form teams AND choose application.]
Working with existing code is…always a challenge but more common than starting from nothing. Posting assignment on Do Not Track.
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.