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Python Using Databases in Python Meet Peewee Queries Are Your Friend

nicole lumpkin
PLUS
nicole lumpkin
Courses Plus Student 5,328 Points

What kind of object is student_record?

I am struggling to understand what kind of object student_record is. So far my understanding is that a Student object translates to three parts that create a whole table.

  1. The table itself (Student)
  2. A column (username)
  3. A column (points)

In the except block, student_record is defined as the following

except IntegrityError:
    student_record = Student.get(username=student['username'])
    student_record.points = student['points']
    student_record.save()

This is where I lose the thread of reasoning re: what kind of obj student_record is. Working from within the parenthesis outwards, I know student['username'] accesses a string value(let's say 'Kenneth'). So now we have the following

student_record = Student.get(username='Kenneth')
  1. I'm assuming the .get() is a query? Y/n
  2. So when we query, do we always use a unique attribute/column as the query?
  3. Is this considered a query instance/object?

-An instance/obj that acts as a handle to the whole row in which it resides?

-An object that allows us to gain access to other attributes/columns within the same row via dot notation? The points attribute for example?

student_record.points = student['points']

Whoever answers this, I'd like to thank you in advance!

Drew Pierce
Drew Pierce
2,079 Points

it's been since I may have done this one but but it sounds like student_record would be a row in the table.

Jorge Gimeno
Jorge Gimeno
5,956 Points

According to peewee's documentation, it returns an instance of Model. http://docs.peewee-orm.com/en/latest/peewee/api.html#Model.get

-Jorge

1 Answer

Hi to add to Jorge answer student_record is an instance of the Student class which inherits from the Peewee model class i.e not sure what you are looking at, hwoever, I would presume the Student class looks something like this

class Student(Model):
    username = CharField(unique=True)
    points = IntegerField()

student_record is an obj oreturned by the Student class based on the query username == 'Kenneth' get() is a query and gets a single record. If you want to get all students with points greate that 10 you would use a SQL query such as:

max_points = Student.select().where(Student.point => 10).order_by(Student.username)

if you want to get all entries in Student you can just use

Student.select()

I hope this helps a little and excuse me if I stated something incorrect :)