NDB Datastore: Data Modeling for a Job website

Question

What is the best way to model data for a job website which has the following elements:

Two types of user accounts: JobSeekers and Employers
Employers can create JobPost entities.
Each JobSeeker can create a Resume entity, and many JobApplication entities.
- JobSeekers can create a JobApplication entity which is related to a JobPost entity.
  - A JobPost entity may receive many JobApplication entities.
  - A JobSeeker may only create one JobApplication entity per JobPost entity.
- A Resume contains one or more instances of Education, Experience, using ndb.StructuredProperty(repeated = True).
  - Each Education contains the following ndb.StringProperty fields: institution, certification, area_of_study
  - While each Experience contains: workplace, job_title.

Brent Washburne Brent Washburne · Accepted Answer · 2013-11-28T01:30:15

Here is a skeleton model that meets your requirements:

class Employer(ndb.Model):
    user = ndb.UserProperty()

class JobPost(ndb.Model):
    employer = ndb.KeyProperty(kind=Employer)

class JobSeeker(ndb.Model):
    user = ndb.UserProperty()
    def apply(self, job_post):
        if JobApplication.query(JobApplication.job_seeker == self.key,
                                JobApplication.job_post == job_post).count(1) == 1:
            raise Exception("Already applied for this position")
        ...

class Resume(ndb.Model):
    job_seeker = ndb.KeyProperty(JobSeeker)
    education = ndb.JsonProperty()
    experience = ndb.JsonProperty()

class JobApplication(ndb.Model):
    job_seeker = ndb.KeyProperty(JobSeeker)
    job_post = ndb.KeyProperty(JobPost)

Notes:

Employer and JobSeeker have the built-in UserProperty to identify and allow them to login.
Resume uses JsonProperty for education and experience to allow for more fields in the future. You can assign a Python dictionary to this field, for example resume.education = {'institution': 'name', 'certification': 'certificate', 'area_of_study': 'major', 'year_graduated': 2013, ...} (I have personally found StructuredProperty to be more pain than gain, and I avoid it now.)
Limiting a JobSeeker to only one JobApplication can be done with the method apply() which checks the JobApplication table for existing applications.

NDB Datastore: Data Modeling for a Job website

1 Answers