60 lines
1.4 KiB
Python
60 lines
1.4 KiB
Python
"""
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Custom Django fields.
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"""
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from django.db import models
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class CharNullField(models.CharField):
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"""
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CharField that stores NULL but returns ''
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"""
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description = "CharField that stores NULL but returns ''"
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def to_python(self, value):
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"""Converts the value into the correct Python object."""
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if isinstance(value, models.CharField):
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return value
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if value is None:
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return ""
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else:
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return value
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def get_db_prep_value(self, value, connection, prepared=False):
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"""Converts value to a backend-specific value."""
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if not prepared:
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value = self.get_prep_value(value)
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if value == "":
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return None
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else:
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return value
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class BigAutoField(models.AutoField):
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"""
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AutoField that uses BigIntegers.
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This exists in Django as of version 1.10.
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"""
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def db_type(self, connection):
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"""
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The type of the field to insert into the database.
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"""
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conn_module = type(connection).__module__
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if "mysql" in conn_module:
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return "bigint AUTO_INCREMENT"
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elif "postgres" in conn_module:
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return "bigserial"
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else:
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return super().db_type(connection)
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def rel_db_type(self, connection):
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"""
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The type to be used by relations pointing to this field.
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Not used until Django 1.10.
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"""
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return "bigint"
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