Modifying JSON attribute

For modifying the JSON attribute value, you use the standard Python list and dict API as well:

  1. >>> Product[1].info['colors'].append('Silver')
  2. >>> Product[1].info['colors']
  3. ['Black', 'Grey', 'Gold', 'Silver']

Now, on commit, the changes will be stored in the database. In order to track the changes made in the JSON structure, Pony uses its own dict and list implementations which inherit from the standard Python dict and list.

Below is a couple more examples of how you can modify the the JSON value.

  1. p = Product[1]
  3. # assigning a new value
  4. p.info['display']['size'] = 4.7
  6. # popping a dict value
  7. display_size = p.info['display'].pop('size')
  9. # removing a dict key using del
  10. del p.info['display']
  12. # adding a dict key
  13. p.info['display']['resolution'] = [1440, 2560]
  15. # removing a list item
  16. del p.info['colors'][0]
  18. # replacing a list item
  19. p.info['colors'][1] = ['White']
  21. # replacing a number of list items
  22. p.info['colors'][1:] = ['White']

All of the actions above are regular Python operations with attributes, lists and dicts.