database homework done

connect.py

@@ -0,0 +1,40 @@
+
+import psycopg2
+
+def connect():
+    """ Connect to the PostgreSQL database server """
+    conn = psycopg2.connect(
+    host="localhost",
+    database="pagila",
+    user="postgres",
+    password="postgres")
+    try:
+
+        # connect to the PostgreSQL server
+        print('Connecting to the PostgreSQL database...')
+
+        # create a cursor
+        cur = conn.cursor()
+
+	# execute a statement
+        cur.execute('select * from "actor"')
+
+        # display the PostgreSQL database server version
+        db_version = cur.fetchmany(5)
+        # db_version = cur.fetchall()
+        # db_version = cur.fetchone()
+        for i in db_version:
+            print(i)
+
+
+	# close the communication with the PostgreSQL
+        cur.close()
+    except (Exception, psycopg2.DatabaseError) as error:
+        print(error)
+    finally:
+        if conn is not None:
+            conn.close()
+            print('Database connection closed.')
+
+if __name__ == '__main__':
+    connect()

create_table.py

@@ -0,0 +1,74 @@
+import psycopg2
+
+def create_tables():
+	""" create tables in the PostgreSQL database"""
+	commands = (
+		"""
+
+		CREATE TABLE IF NOT EXISTS public.books
+(
+    book_id serial NOT NULL ,
+    title character varying(100) COLLATE pg_catalog."default" NOT NULL,
+    author character varying(100) COLLATE pg_catalog."default",
+    genre character varying(100) COLLATE pg_catalog."default",
+    pages integer,
+    added_date date DEFAULT CURRENT_DATE,
+    quantity integer NOT NULL,
+    CONSTRAINT books_pkey PRIMARY KEY (book_id),
+    CONSTRAINT uk_books UNIQUE (title, author)
+)
+		""",
+		""" CREATE TABLE IF NOT EXISTS public.user_action
+(
+    action_id serial NOT NULL,
+    user_id integer NOT NULL,
+    book_id integer NOT NULL,
+    borrow boolean DEFAULT false,
+    reading boolean DEFAULT false,
+    read boolean DEFAULT false,
+    fav boolean DEFAULT false,
+    will_read boolean DEFAULT false,
+    CONSTRAINT pk_action_id PRIMARY KEY (action_id)
+)
+		""",
+ 		"""CREATE TABLE IF NOT EXISTS public.users
+(
+    user_id serial NOT NULL,
+    user_name character varying(100) NOT NULL,
+    CONSTRAINT pk_user_id PRIMARY KEY (user_id),
+    CONSTRAINT uk_user_name UNIQUE (user_name)
+)
+  """,
+  		"""ALTER TABLE IF EXISTS public.user_action
+    ADD CONSTRAINT fk_books_actions FOREIGN KEY (book_id)
+    REFERENCES public.books (book_id) MATCH SIMPLE
+    ON UPDATE NO ACTION
+    ON DELETE NO ACTION;""",
+	"""ALTER TABLE IF EXISTS public.user_action
+    ADD FOREIGN KEY (user_id)
+    REFERENCES public.users (user_id) MATCH SIMPLE
+    ON UPDATE NO ACTION
+    ON DELETE NO ACTION
+    NOT VALID;
+
+	"""
+  )
+	conn = psycopg2.connect(
+	host="localhost",
+	database="library",
+	user="postgres",
+	password="postgres")
+	try:
+		cur = conn.cursor()
+		for command in commands:
+			cur.execute(command)
+		cur.close()
+		conn.commit()
+	except (Exception, psycopg2.DatabaseError) as error:
+		print(error)
+	finally:
+		if conn is not None:
+			conn.close()
+
+if __name__ == '__main__':
+	create_tables()

exercise5.py

@@ -0,0 +1,48 @@
+import psycopg2
+# from config import config
+
+
+def create_tables():
+	""" create tables in the PostgreSQL database"""
+	commands = (
+		"""
+
+		CREATE TABLE IF NOT EXISTS public.students (
+			student_id SERIAL PRIMARY KEY,
+			student_name VARCHAR(255) NOT NULL
+		)
+		""",
+		""" CREATE TABLE IF NOT EXISTS public.teachers (
+				teacher_id SERIAL PRIMARY KEY,
+				teacher_name VARCHAR(255) NOT NULL
+				)
+		""")
+	conn = psycopg2.connect(
+	host="localhost",
+	database="PyCoders",
+	user="postgres",
+	password="postgres")
+	try:
+		cur = conn.cursor()
+		for command in commands:
+			cur.execute(command)
+
+		student_list=['sefa','saffet','ilter']		
+		for i in student_list:
+			postgres_insert_query = f""" INSERT INTO students (student_name) VALUES ('{i}')"""
+			cur.execute(postgres_insert_query)
+
+		teacher_list=['irfan','semih','irem']
+		for i in teacher_list:
+			postgres_insert_query2 = f""" INSERT INTO teachers (teacher_name) VALUES ('{i}')"""
+			cur.execute(postgres_insert_query2)
+		cur.close()
+		conn.commit()
+	except (Exception, psycopg2.DatabaseError) as error:
+		print(error)
+	finally:
+		if conn is not None:
+			conn.close()
+
+if __name__ == '__main__':
+	create_tables()