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create_tables.py
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create_tables.py
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import psycopg2
from sql_queries import create_table_queries, drop_table_queries
t_host = "localhost" # either a domain name, an IP address, or "localhost"
t_port = "5432" # This is the default postgres port
t_dbname = "postgres"
t_user = "admin"
t_pw = "secret"
def create_database():
"""
- Creates and connects to the sparkifydb
@return: cursor and connection to sparkifydb
"""
# connect to default database
conn = psycopg2.connect(host=t_host, port=t_port, dbname=t_dbname, user=t_user, password=t_pw)
conn.set_session(autocommit=True)
cur = conn.cursor()
# create sparkify database with UTF8 encoding
cur.execute("DROP DATABASE IF EXISTS sparkifydb")
cur.execute("CREATE DATABASE sparkifydb WITH ENCODING 'utf8' TEMPLATE template0")
# close connection to default database
conn.close()
# connect to sparkify database
conn = psycopg2.connect("host=127.0.0.1 dbname=sparkifydb user=admin password=secret")
cur = conn.cursor()
return cur, conn
def drop_tables(cur, conn):
"""
Drops each table using the queries in `drop_table_queries` list.
@param cur:
@param conn:
"""
for query in drop_table_queries:
cur.execute(query)
conn.commit()
def create_tables(cur, conn):
"""
Creates each table using the queries in `create_table_queries` list.
@param cur:
@param conn:
"""
for query in create_table_queries:
cur.execute(query)
conn.commit()
def main():
"""
- Drops (if exists) and Creates the sparkify database.
- Establishes connection with the sparkify database and gets
cursor to it.
- Drops all the tables.
- Creates all tables needed.
- Finally, closes the connection.
"""
cur, conn = create_database()
drop_tables(cur, conn)
create_tables(cur, conn)
conn.close()
if __name__ == "__main__":
main()