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Reading from resource with `.read()`

.read()

Retriving data from resource (db) is done using .read() method

def read(self, *args, **kwargs) -> Any

Read is called from resource of table property (table property is called from object of epure)

Read takes either key-word arguments or result of creating query with @escript decorator (read abput @escript here):

Using .read() 

from epure import epure, escript

@epure()
class MyEpure:
    str_field:str

    @classmethod
    @escript
    def my_query_creator(cls):
        query = cls.md.str_field == "a key-word arg"

...
# creating and saving instances
...
Now to retrive your instances you can go either with:

Key-word approach 

MyEpure.resource.read(str_field="a key-word arg") # [[<MyEpure obj>, <MyEpure obj>]]
Or @escript decorator approach 
query = MyEpure.my_query_creator()
MyEpure.resource.read(query) # [[<MyEpure obj>, <MyEpure obj>]]

Using read() with **kwargs parameters

**kwargs with read() is convinient when you:

  • know attribute by which you want to get set of objects

  • have data_id (UUID) of specific object

Then you can use .read() method that takes key-word arguments and allows this ready to hand approach of getting objects:

Using read() with **kwargs

We will take data_id (UUID) from saved object:

article_one_data_id = article_one.data_id # -> UUID4 # (1)!
Passing UUID as data_id kwarg will return object with that specific UUID: 
# reading by unique data_id of article will return one object
my_articles = obj1.table.read(data_id=article_one_data_id)[0] # -> [<Article object at 0x0...>]
Or if you want to retrieve saved instances by some attribute of object: 
# multiple attrs of article
my_articles = Article.resource.read(str_attr="Why Epure is the best ORM?", times_published=3) # -> [[<Article object at 0x0...,>, ...]]

  1. data_id is a unique UUID object identifier that Epure uses to discriminate different objects