def drop_empty_create_table(model):
"""
Drop an empty table (if it exists) and then create a table
"""
table_name = model._meta.db_table
if model.table_exists():
query = "SELECT CASE WHEN EXISTS (SELECT 1 FROM {}) THEN True ELSE False END".format(
table_name)
result = db.execute_sql(query).fetchall()
if result and result[0] and result[0][0]:
logger.error(
'%s table already exists and has data, cant be dropped',
table_name)
raise Exception('Table already exists and has data')
else:
try:
model.drop_table()
logger.info('%s table dropped', table_name)
model.create_table()
logger.info('%s table created', table_name)
except Exception as e:
db.rollback()
logger.error('%s: %s', type(e).__name__, e)
else:
model.create_table()
logger.info('%s table created', table_name)
def rename_column(model, old_column_name, new_column_name):
"""
Add column to table if it doesn't exist
"""
table_name = model._meta.db_table
if model.table_exists():
try:
migrate(
migrator.rename_column(table_name, old_column_name,
new_column_name))
logger.info('%s column is renamed to %s', old_column_name,
new_column_name)
except Exception as e:
db.rollback()
logger.error('%s: %s', (type(e).__name__, e))
else:
logger.error('No table with name %s found', table_name)
def add_column(model, column_name, field):
"""
Add column to table if it doesn't exist
"""
table_name = model._meta.db_table
if model.table_exists():
query = "SELECT True FROM information_schema.columns WHERE table_name='{}' and column_name='{}'".format(
table_name, column_name)
result = db.execute_sql(query).fetchall()
if result and result[0] and result[0][0]:
logger.info('%s column is already in the table %s', column_name,
table_name)
else:
try:
migrate(migrator.add_column(table_name, column_name, field))
logger.info('%s column is added to the table %s', column_name,
table_name)
except Exception as e:
db.rollback()
logger.error('%s: %s', type(e).__name__, e)
else:
logger.error('No table with name %s found', table_name)
def delete_column(model, column_name):
"""
Delete column from table if it exist
"""
table_name = model._meta.db_table
if model.table_exists():
query = "SELECT True FROM information_schema.columns WHERE table_name='{}' and column_name='{}'".format(
table_name, column_name)
a = db.execute_sql(query).fetchall()
if a and a[0] and a[0][0]:
try:
migrate(migrator.drop_column(table_name, column_name))
logger.info('%s column is removed from the table %s',
column_name, table_name)
except Exception as e:
db.rollback()
logger.error('%s: %s', type(e).__name__, e)
raise e
else:
logger.info('%s column is not present in the table %s',
column_name, table_name)
else:
logger.error('No table with name %s found', table_name)