Accessing SQLAlchemy table column names with variables

Question

I have a dictionary of the sort

{'category_id': 'women_shoes', 'product_id': 486778462L}

Here category_id is my table name in MYSQL database. I am trying to get the specified product_id from the table women_shoes. I am able to achieve this through this code

class_name = globals()[each_itemset["category_id"].capitalize()]
table_values = session.query(class_name).filter(class_name.product_id == each_itemset["product_id"])
for each in table_values:               
    print each.brand_name               
    name = "brand_name"

Up til here things work fine and I am able to get the brand_name of the product. What I want is that instead of giving the statement

print each.brand_name

I want to do

name = "brand_name"
print each.name

because I don't want to specify the exact table name myself. I want to get the table column names from class_name.table.columns.keys(), and iterate over it to get each column name and supply it to name one by one.

I get the following error when I do this

Traceback (most recent call last):
  File "main_site.py", line 14, in <module>
    json_data = db_access.get_styles_from_db("work")
  File "C:\Python27\Projects\Clothe Studio Recommendation Project\util\db_access.py", line 149, in get_styles_from_db
    calc_outfit_scores(outfit_dict, session)
  File "C:\Python27\Projects\Clothe Studio Recommendation Project\util\db_access.py", line 192, in calc_outfit_scores
    print each.name
AttributeError: 'Women_shoes' object has no attribute 'name'

I have searched through the SQLAlchemy documentation and SO but don't seem to find an answer. What should be done in this scenario? Your help is appreciated.

You should review your question before submitting to ensure it's conveying your question clearly. For example, where did you define each_itemset? We can guess each_itemset is the dict you've defined on top but still just take this as a tip to review well and then submit. You will get better responses too! — Amir
– Amir, Commented Apr 19, 2016 at 22:08
Im not really sure what the goal is, your objected statement is a little odd. You assign a static string to a variable and then try to access a attribute that doesnt exist. but if you are trying to see the object dictionary it could be as simple as each.__dict__ using the builtin python. or assign name = each.brand_name and then just use name instead of each.name. — Busturdust
– Busturdust, Commented Apr 19, 2016 at 22:12
@Busturdust Thanks for your solution. each.__dict__ did the trick. Whereas name = each.brand_name gave me the same error as before. I had tried that already. each.__dict__ is the way to go. If you can give it an as answer, I can mark it. Thanks once again — Falconic
– Falconic, Commented Apr 19, 2016 at 22:18

Busturdust · Accepted Answer · 2016-04-19 22:29:52Z

1

If you are simply trying to generate a dictionary of the objects attributes: values, you can use the built in python object attribute dictionay __dict__

in your case

for each in table_values:               
    print each.__dict__

If there are any Foreign Keys or cast like mechanisms youd like to follow / use, you will need implement a custom to_dict() method for the class, and use that

answered Apr 19, 2016 at 22:29

Busturdust

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Comments

flazzarini · Accepted Answer · 2016-04-20 15:42:25Z

0

You could use getattr to retrieve the attribute in a more generic way.

for each in table_values:      
    name = 'brand_name'
    value = getattr(each, name)
    print(value)

answered Apr 20, 2016 at 15:42

flazzarini

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