# Sebastian Raschka, 2014
# Adding a new column to an existing SQLite database

import sqlite3

sqlite_file = 'my_first_db.sqlite'    # name of the sqlite database file
table_name = 'my_table_2'	# name of the table to be created
id_column = 'my_1st_column' # name of the PRIMARY KEY column
new_column1 = 'my_2nd_column'  # name of the new column
new_column2 = 'my_3rd_column'  # name of the new column
column_type = 'TEXT' # E.g., INTEGER, TEXT, NULL, REAL, BLOB
default_val = 'Hello World' # a default value for the new column rows

# Connecting to the database file
conn = sqlite3.connect(sqlite_file)
c = conn.cursor()

# A) Adding a new column without a row value
c.execute("ALTER TABLE {tn} ADD COLUMN '{cn}' {ct}"\
        .format(tn=table_name, cn=new_column1, ct=column_type))

# B) Adding a new column with a default row value
c.execute("ALTER TABLE {tn} ADD COLUMN '{cn}' {ct} DEFAULT '{df}'"\
        .format(tn=table_name, cn=new_column2, ct=column_type, df=default_val))

# Committing changes and closing the connection to the database file
conn.commit()
conn.close()