def migrate_currencies(apps, schema_editor):
"""
Migrate from the 'old' method of handling currencies,
to the new method which uses the django-money library.
Previously, we created a custom Currency model,
which was very simplistic.
Here we will attempt to map each existing "currency" reference
for the SupplierPriceBreak model, to a new django-money compatible currency.
"""
logger.info("Updating currency references for SupplierPriceBreak model...")
# A list of available currency codes
currency_codes = CURRENCIES.keys()
cursor = connection.cursor()
# The 'suffix' field denotes the currency code
response = cursor.execute(
'SELECT id, suffix, description from common_currency;')
results = cursor.fetchall()
remap = {}
for index, row in enumerate(results):
pk, suffix, description = row
suffix = suffix.strip().upper()
if suffix not in currency_codes: # pragma: no cover
logger.warning(f"Missing suffix: '{suffix}'")
while suffix not in currency_codes:
# Ask the user to input a valid currency
print(f"Could not find a valid currency matching '{suffix}'.")
print("Please enter a valid currency code")
suffix = str(input("> ")).strip()
if pk not in remap.keys():
remap[pk] = suffix
# Now iterate through each SupplierPriceBreak and update the rows
response = cursor.execute(
'SELECT id, cost, currency_id, price, price_currency from part_supplierpricebreak;'
)
results = cursor.fetchall()
count = 0
for index, row in enumerate(results):
pk, cost, currency_id, price, price_currency = row
# Copy the 'cost' field across to the 'price' field
response = cursor.execute(
f'UPDATE part_supplierpricebreak set price={cost} where id={pk};')
# Extract the updated currency code
currency_code = remap.get(currency_id, 'USD')
# Update the currency code
response = cursor.execute(
f"UPDATE part_supplierpricebreak set price_currency= '{currency_code}' where id={pk};"
)
count += 1
if count > 0:
logger.info(f"Updated {count} SupplierPriceBreak rows")
def get_currency_codes(self):
return sorted(list(CURRENCIES.keys()), key=str.lower)
