sqlalchemyseed 0.3.0.dev2

SQLAlchemy seeder.

sqlalchemyseed

Sqlalchemy seeder. Supports nested relationships.

Installation

pip install sqlalchemyseed

Dependencies

• SQAlchemy>=1.4.0

Getting Started

# main.py
from sqlalchemyseed import load_entities_from_json, Seeder
from tests.db import session

# load entities
entities = load_entities_from_json('tests/test_data.json')

# Initializing Seeder
seeder = Seeder()  # or Seeder(session)

# Seeding
seeder.session = session  # assign session if no session assigned before seeding
seeder.seed(entities)

# Committing
session.commit()  # or seeder.session.commit()

Seeder vs. HybridSeeder

• Seeder supports model and data key fields.
• Seeder does not support model and filter key fields.
• HybridSeeder supports model and data, and model and filter key fields.
• HybridSeeder enables to query existing objects from the session and assigns it with the relationship.

When to use HybridSeeder and 'filter' key field?

from sqlalchemyseed import HybridSeeder
from tests.db import session

data = {
    "model": "models.Parent",
    "obj": {
        "child": {
            "model": "models.Child",
            "filter": {
                "age": 5
            }
        }
    }
}

# Assuming that Child(age=5) exists in the database or session,
#  then we should use 'filter' instead of 'obj'

# When seeding instances that has 'filter' key, then use HybridSeeder, otherwise use Seeder.
seeder = HybridSeeder(session)
seeder.seed(data)

No Relationship

// test_data.json
[
    {
        "model": "models.Person",
        "data": {
            "name": "You",
            "age": 18
        }
    },
    // when you have two or more objects of the same model, you can
    {
        "model": "models.Person",
        "data": [
            {
                "name": "You",
                "age": 18
            },
            {
                "name": "Still You But Older",
                "age": 40
            }
        ]
    }
]

Relationships

In adding a relationship attribute, add prefix '!' to the key in order to identify it.

One to One

// test_data.json
[
    {
        "model": "models.Person",
        "data": {
            "name": "John",
            "age": 18,
            // creates a job object
            "!job": {
                "model": "models.Job",
                "data": {
                    "job_name": "Programmer",
                }
            }
        }
    },
    // or this, if you want to add relationship that exists
    // in your database use 'filter' instead of 'obj'
    {
        "model": "models.Person",
        "data": {
            "name": "Jeniffer",
            "age": 18,
            "!job": {
                "model": "models.Job",
                "filter": {
                    "job_name": "Programmer",
                }
            }
        }
    }
]

One to Many

//test_data.json
[
    {
        "model": "models.Person",
        "data": {
            "name": "John",
            "age": 18,
            "!items": [
                {
                    "model": "models.Item",
                    "data": {
                        "name": "Pencil"
                    }
                },
                {
                    "model": "models.Item",
                    "data": {
                        "name": "Eraser"
                    }
                }
            ]
        }
    }
]

Example of Nested Relationships

{
    "model": "models.Parent",
    "data": {
        "name": "John Smith",
        "!children": [
            {
                "model": "models.Child",
                "data": {
                    "name": "Mark Smith",
                    "!children": [
                        {
                            "model": "models.GrandChild",
                            "data": {
                                "name": "Alice Smith"
                            }
                        }
                    ]
                }
            }
        ]
    }
}