CODEWITHSUNDEEP
pythondjangodjango-models
dracarys
dracarys

Reputation: 1121

Django Automatically load data in a database table on creation

I want to automatically load predefined data into a database table when python manage.py makemigrations is run

For example if I have a model

class Test(models.Model):
    id = models.AutoField(primary_key=True)
    name = models.CharField(max_length=2)
    value = models.IntegerField(default=0)

    def __str__(self):
        return str(self.name)

I want this database table to populate itself with following data on creation (when python manage.py makemigrations & python manage.py migrate is run)

id|name|value|
--------------
1 | AA |  0  |
2 | AB |  0  |
3 | AC |  0  |
4 | AD |  0  |
5 | AE |  0  |
6 | AF |  0  |
7 | AG |  0  |
8 | AH |  0  |
9 | AI |  0  |
10| AJ |  0  |
11| AK |  0  |
. |    |     |
. |    |     |
. |    |     |
xx| ZZ |  0  | 
--------------

Upvotes: 0

Views: 1423

Answers (1)

Diego Magalhães
Diego Magalhães

Reputation: 1762

You can do it with fixtures.

First, you don't need this id field, by default, Django gives each model exactly this field id = models.AutoField(primary_key=True)

class Test(models.Model):
    name = models.CharField(max_length=2)
    value = models.IntegerField(default=0)

    def __str__(self):
        return str(self.name)

Then go to your app and create a fixtures directory.

I create this code to generate your fixture:

from itertools import product
import json


def generate_fixture():
    char_pairs = list(product(map(chr, range(97, 123)), repeat=2))
    data = []
    for i in range(0, len(char_pairs)):
        data.append(
            {
                "model": "yourappname.test",  # change yourappname
                "pk": i+1,
                "fields": {"name": ''.join(char_pairs[i]), "value": 0}
            },
        )
    file = open('filename.json', 'w')  # change filename 
    file.write(json.dumps(data, indent=2))
    file.close()


if __name__ == "__main__":
    generate_fixture()

change yourappname and filename before run this code.

The result is a json with 676 objects from aa to zz using the following structure:

[
  {
    "model": "yourappname.test",
    "pk": 1,
    "fields": {
      "name": "AA",
      "value": 0
    }
  },
]

Finally, copy and paste the json file inside yourapp/fixtures and run python manage.py loaddata jsonfilename

With json inside the fixture folder, if you clean the database, just run the loaddata command again.

Django - Providing data with fixtures

Upvotes: 4

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