Samarvir singh

README.md

@@ -65,73 +65,126 @@ Before you begin, look at the queries in `setup.sql` to get a hint as to the
 column names in the following tables. We'll use `setup.sql` later.
 
 * Create a table called `track` that holds information about a music track. It should contain:
+
   * An autoincrementing `id`
   * A title (of type `VARCHAR`, probably)
   * A reference to an `id` in table `album` (the album the track is on). This
     should be a _foreign key_.
 
+CREATE TABLE track (id INTEGER PRIMARY KEY AUTOINCREMENT,title VARCHAR(128) NOT NULL, album_ID INT REFERENCES album(id));
+
+
 * Create a table called `artist_album` to connect artists to albums. (Note that
   an artist might have several albums and an album might be created by multiple
   artists.)
   * Use foreign keys for this, as well.
 
+ CREATE TABLE artist_album(id INTEGER PRIMARY KEY AUTOINCREMENT,album_ID INT REFERENCES album(id),artist_ID INT REFERENCES artist(id));
+
+
 * Run the queries in the file `setup.sql`. This will populate the tables.
   * Fix any errors at this point by making sure your tables are correct.
   * `DROP TABLE` can be used to delete a table so you can recreate it with
     `CREATE TABLE`.
 
+.read setup.sql
+
 * Write SQL `SELECT` queries that:
   * Show all albums.
+  SELECT * FROM album;
   * Show all albums made between 1975 and 1990.
+  SELECT * FROM album WHERE release_year > 1975 AND release_year < 1990;
   * Show all albums whose names start with `Super D`.
+
+  SELECT * FROM album WHERE title LIKE 'Super D%';
+
   * Show all albums that have no release year.
 
+  SELECT * FROM album WHERE release_year is NULL;
+
 * Write SQL `SELECT` queries that:
   * Show all track titles from `Super Funky Album`.
-  * Same query as above, but rename the column from `title` to `Track_Title` in
-    the output.
+
+  SELECT track.title FROM track,album WHERE album.title = 'Super Funky Album' AND album.id = album_id;
+
+  * Same query as above, but rename the column from `title` to `Track_Title` in the output.
+
+  SELECT track.title AS Track_Title FROM track,album WHERE album.title ='Super Funky Album' AND album.id = album_id;
 
   * Select all album titles by `Han Solo`.
 
+SELECT * FROM artist,artist_album WHERE artist.name = 'Han Solo' AND artist.id = artist_id;
+
   * Select the average year all albums were released.
 
+SELECT AVG(release_year) FROM album;
+
   * Select the average year all albums by `Leia and the Ewoks` were released.
 
-  * Select the number of artists.
+SELECT AVG(release_year) FROM artist,artist_album,album  WHERE artist.name = 'Leia and the Ewoks' AND artist.id = artist_id;
 
+  * Select the number of artists.
+SELECT COUNT(ID) from artist;
   * Select the number of tracks on `Super Dubstep Album`.
 
+  SELECT count(track.title) AS Track_Title FROM track,album WHERE album.title ='Super Dubstep Album' AND album.id = album_id;
+
 ### Exercises, Day 2
 
 Create a database for taking notes.
 
 * What are the columns that a note table needs?
 
+CREATE TABLE notes( id INTEGER PRIMARY KEY AUTOINCREMENT, title VARCHAR(128) NOT NULL, body VARCHAR(256) , Timestamp DATETIME DEFAULT CURRENT_TIMESTAMP, author_ID INT REFERENCES author(id));
+
 * If you have a timestamp field, how do you auto-populate it with the date?
+Timestamp DATETIME DEFAULT CURRENT_TIMESTAMP
 
 * A note should have a foreign key pointing to an author in an author table.
 
+
+author_ID INT REFERENCES author(id)
+
 * What columns are needed for the author table?
 
+id
+name
+
+CREATE TABLE author( id INTEGER PRIMARY KEY AUTOINCREMENT, name varchar(128) NOT NULL);
 Write queries that:
 
 * Insert authors to the author table.
 
+ INSERT INTO author (name) VALUES ("john green");
+
 * Insert notes to the note table.
 
+INSERT INTO notes (title, body, author_ID) VALUES ("title goes here", "body here", 1);
+
 * Select all notes by an author's name.
 
+SELECT * FROM notes,author WHERE author.name = "john green" AND author.id = author_id;
+
 * Select author for a particular note by note ID.
 
+SELECT * FROM notes,author WHERE notes.id = 1  AND author.id = author_id;
+
 * Select the names of all the authors along with the number of notes they each have. (Hint: `GROUP BY`.)
 
+SELECT COUNT(author_id),author.name  
+  FROM author, notes 
+  WHERE author.id = notes.author_id
+  GROUP BY author.name; 
 * Delete authors from the author table.
   > Note that SQLite doesn't enforce foreign key constrains by default. You have
   > to enable them by running `PRAGMA foreign_keys = ON;` before your queries.
 
   * What happens when you try to delete an author with an existing note?
+   DELETE FROM author WHERE name = "samarv";
   * How can you prevent this?
 
+  cascading?
+
 Submit a file `notes.sql` with the queries that build (`CREATE TABLE`/`INSERT`)
 and query the database as noted above.
 

notes.sql

@@ -0,0 +1,25 @@
+CREATE TABLE notes( id INTEGER PRIMARY KEY AUTOINCREMENT, title VARCHAR(128) NOT NULL, body VARCHAR(256) , Timestamp DATETIME DEFAULT CURRENT_TIMESTAMP, author_ID INT REFERENCES author(id));
+
+CREATE TABLE author( id INTEGER PRIMARY KEY AUTOINCREMENT, name varchar(128) NOT NULL);
+
+INSERT INTO author (name) VALUES ("john green");
+INSERT INTO author (name) VALUES ("hank green");
+INSERT INTO author (name) VALUES ("samarv");
+
+INSERT INTO notes (title, body, author_ID) VALUES ("title goes here", "body here", 1);
+INSERT INTO notes (title, body, author_ID) VALUES ("title goes here", "body here", 1);
+INSERT INTO notes (title, body, author_ID) VALUES ("title goes here", "body here", 1);
+
+SELECT * FROM notes,author WHERE author.name = "john green" AND author.id = author_id;
+
+SELECT * FROM notes,author WHERE notes.id = 1  AND author.id = author_id;
+
+
+SELECT COUNT(author_id),author.name  
+  FROM author, notes 
+  WHERE author.id = notes.author_id
+  GROUP BY author.name; 
+
+PRAGMA foreign_keys = ON;
+DELETE FROM author WHERE name = "samarv";
+