Martin/week2

week-1/mandatory/2-classes-db/task.md

@@ -7,10 +7,163 @@ Below you will find a set of tasks for you to complete to set up a databases of
 To submit this homework write the correct commands for each question here:
 
 ```sql
+1. martinboylan=> createdb cyf_classes //This bit didnt work I only realise at the end.
+2.
+cyf_hotels=> CREATE TABLE mentors (
+cyf_hotels(> name VARCHAR(30) NOT NULL,
+cyf_hotels(> years INT NOT NULL,
+cyf_hotels(> address VARCHAR(120) NOT NULL,
+cyf_hotels(> language VARCHAR(20)
+cyf_hotels(> );
+3.
+cyf_hotels=> INSERT INTO mentors (name, years, address, language) VALUES ('Paul', 8, '5 Welsh Street', 'PYTHON');
+INSERT 0 1
+cyf_hotels=> INSERT INTO mentors (name, years, address, language) VALUES ('Dan', 5, '5 Irishh Street', 'JAVASCRIPT');
+INSERT 0 1
+cyf_hotels=> INSERT INTO mentors (name, years, address, language) VALUES ('Steve', 14, '5 Welsh Street', 'JAVA');
+INSERT 0 1
+cyf_hotels=> INSERT INTO mentors (name, years, address, language) VALUES ('Pauline', 41, '8 Filbert Street', 'HTML');
+INSERT 0 1
+cyf_hotels=> INSERT INTO mentors (name, years, address, language) VALUES ('Sadhaf', 4, '12 Filbert Roadt', 'CSS');
+INSERT 0 1
 
-
+4.
+cyf_hotels=> CREATE TABLE students (
+cyf_hotels(> name VARCHAR(30),
+cyf_hotels(> address VARCHAR(120),
+cyf_hotels(> graduated BOOLEAN
+cyf_hotels(> );
 ```
 
+5. cyf_hotels=> INSERT INTO students (name, address, graduated) VALUES ('Daveen', 25, True);
+   INSERT 0 1
+   cyf_hotels=> INSERT INTO students (name, address, graduated) VALUES ('Dave', 28, True);
+   INSERT 0 1
+   cyf_hotels=> INSERT INTO students (name, address, graduated) VALUES ('Sam', 233, False);
+   INSERT 0 1
+   cyf_hotels=> INSERT INTO students (name, address, graduated) VALUES ('Joyce', 27, True);
+   INSERT 0 1
+   cyf_hotels=> INSERT INTO students (name, address, graduated) VALUES ('Frank', 19, True);
+   INSERT 0 1
+   cyf_hotels=> INSERT INTO students (name, address, graduated) VALUES ('Tracey', 25, False);
+   INSERT 0 1
+   cyf_hotels=> INSERT INTO students (name, address, graduated) VALUES ('Gennady', 34, True);
+   INSERT 0 1
+   cyf_hotels=> INSERT INTO students (name, address, graduated) VALUES ('Susan', 30, True);
+   INSERT 0 1
+   cyf_hotels=> INSERT INTO students (name, address, graduated) VALUES ('Riccardo', 45, False);
+   INSERT 0 1
+   cyf_hotels=> INSERT INTO students (name, address, graduated) VALUES ('Mark', 25, True);
+   INSERT 0 1
+6.
+
+cyf_hotels=> SELECT \* FROM mentors;
+name | years | address | language  
+---------+-------+------------------+------------
+Paul | 8 | 5 Welsh Street | PYTHON
+Dan | 5 | 5 Irishh Street | JAVASCRIPT
+Steve | 14 | 5 Welsh Street | JAVA
+Pauline | 41 | 8 Filbert Street | HTML
+Sadhaf | 4 | 12 Filbert Roadt | CSS
+(5 rows)
+
+cyf_hotels=> SELECT \* FROM students;
+name | address | graduated
+----------+---------+-----------
+Daveen | 25 | t
+Dave | 28 | t
+Sam | 233 | f
+Joyce | 27 | t
+Frank | 19 | t
+Tracey | 25 | f
+Gennady | 34 | t
+Susan | 30 | t
+Riccardo | 45 | f
+Mark | 25 | t
+(10 rows)
+
+7. cyf_hotels=> CREATE TABLE classes (
+   cyf_hotels(> id SERIAL PRIMARY KEY,
+   cyf_hotels(> leadmentor VARCHAR(30) NOT NULL,
+   cyf_hotels(> topic VARCHAR(30) NOT NULL,
+   cyf_hotels(> date DATE,
+   cyf_hotels(> location VARCHAR(30) NOT NULL
+   cyf_hotels(> );
+
+8. cyf_hotels=> INSERT INTO classes (leadmentor, topic, date, location)
+   cyf_hotels-> VALUES ('Karen', 'JAVASCRIPT', '2021-10-20', 'Birmingham');
+   INSERT 0 1
+   cyf_hotels=> INSERT INTO classes (leadmentor, topic, date, location) VALUES ('Jeremiah', 'JAVA', '2021-04-15', 'Manchester');
+   INSERT 0 1
+   cyf_hotels=> INSERT INTO classes (leadmentor, topic, date, location) VALUES ('Apollo', 'CSS', '2021-07-30', 'London');
+
+9. cyf_hotels=> CREATE TABLE attendsclass (
+   cyf_hotels(> id SERIAL PRIMARY KEY,
+   cyf_hotels(> studentname VARCHAR(30),
+   cyf_hotels(> classid INT
+   cyf_hotels(> );
+
+10. cyf_hotels=> SELECT \* FROM mentors WHERE years > 5;
+    name | years | address | language
+    ---------+-------+------------------+----------
+    Paul | 8 | 5 Welsh Street | PYTHON
+    Steve | 14 | 5 Welsh Street | JAVA
+    Pauline | 41 | 8 Filbert Street | HTML
+    (3 rows)
+
+cyf_hotels=> SELECT \* FROM mentors WHERE language = 'JAVASCRIPT';
+name | years | address | language  
+------+-------+-----------------+------------
+Dan | 5 | 5 Irishh Street | JAVASCRIPT
+(1 row)
+
+cyf_hotels=> SELECT \* FROM students WHERE graduated = true;
+name | address | graduated
+---------+---------+-----------
+Daveen | 25 | t
+Dave | 28 | t
+Joyce | 27 | t
+Frank | 19 | t
+Gennady | 34 | t
+Susan | 30 | t
+Mark | 25 | t
+(7 rows)
+
+cyf_hotels=> SELECT \* FROM classes WHERE date < '2020-06-01';
+id | leadmentor | topic | date | location
+----+------------+-------+------+----------
+(0 rows)
+
+cyf_hotels=> ALTER TABLE students ADD COLUMN classid INT;
+ALTER TABLE
+
+cyf_hotels=> UPDATE students SET classid = 1 WHERE graduated = false;
+UPDATE 3
+cyf_hotels=> SELECT \* FROM students;
+name | address | graduated | classid
+----------+---------+-----------+---------
+Daveen | 25 | t |  
+ Dave | 28 | t |  
+ Joyce | 27 | t |  
+ Frank | 19 | t |  
+ Gennady | 34 | t |  
+ Susan | 30 | t |  
+ Mark | 25 | t |  
+ Sam | 233 | f | 1
+Tracey | 25 | f | 1
+Riccardo | 45 | f | 1
+(10 rows)
+
+cyf_hotels=> SELECT name FROM students WHERE classid = 1;
+name
+
+---
+
+Sam
+Tracey
+Riccardo
+(3 rows)
+
 When you have finished all of the questions - open a pull request with your answers to the `Databases-Homework` repository.
 
 ## Task
@@ -23,9 +176,9 @@ When you have finished all of the questions - open a pull request with your answ
 6. Verify that the data you created for mentors and students are correctly stored in their respective tables (hint: use a `select` SQL statement).
 7. Create a new `classes` table to record the following information:
 
-   - A class has a leading mentor
-   - A class has a topic (such as Javascript, NodeJS)
-   - A class is taught at a specific date and at a specific location
+    - A class has a leading mentor
+    - A class has a topic (such as Javascript, NodeJS)
+    - A class is taught at a specific date and at a specific location
 
 8. Insert a few classes in the `classes` table
 9. We now want to store who among the students attends a specific class. How would you store that? Come up with a solution and insert some data if you model this as a new table.