How to use the django.db.models.CharField function in Django

class Status(models.Model):
    StatusID = models.IntegerField(primary_key=True)
    StatusName = models.CharField(max_length=30)
    
    def __unicode__(self):
        return self.StatusName
    
    class Meta:
        db_table = 'Status'


class Category(models.Model):
    CategoryID = models.AutoField(primary_key=True)
    CategoryName = models.CharField(max_length=30)
    
    def __unicode__(self):
        return self.CategoryName
    
    class Meta:
        db_table = 'Categories'


class Tool(models.Model):
    ToolID = models.AutoField(primary_key=True)
    ToolName = models.CharField(max_length=30)
    Category = models.ForeignKey(Category, db_column="CategoryID", related_name="Tools")
    ToolDescription = models.CharField(max_length=100, null=True, blank=True)
    User = models.ForeignKey(User, editable=False)
    PublicInd = models.BooleanField(default=False)

from django.contrib.auth.models import User
from django.db import models
from apps.thirdparty.userroles import roles
import pdb

class UserRole(models.Model):
    user = models.ForeignKey(User, related_name='role')
    name = models.CharField(max_length=100, choices=roles.choices)
    child = models.CharField(max_length=100, blank=True)
    _valid_roles = roles

    @property
    def profile(self):
        if not self.child:
            return None
        return getattr(self, self.child)

    def __eq__(self, other):
        return self.name == other
        # return self.name == other.name

    def __getattr__(self, name):
        if name.startswith('is_'):
            role = getattr(self._valid_roles, name[3:], None)

class Migration(migrations.Migration):

    dependencies = [
        ('workflow', '0023_auto_20180425_0136'),
    ]

    operations = [
        migrations.AddField(
            model_name='dashboard',
            name='dashboard_uuid',
            field=models.UUIDField(blank=True, null=True, default=None, verbose_name='Dashboard UUID'),
        ),
        migrations.AddField(
            model_name='dashboard',
            name='public_url_token',
            field=models.CharField(blank=True, max_length=255, null=True),
        ),
        migrations.AlterField(
            model_name='dashboard',
            name='public',
            field=models.CharField(blank=True, choices=[('org', 'Organization'), ('url', 'URL'), ('all', 'All')], max_length=5, null=True),
        ),

item_458_choices = [(u'produces', u'produces')]
    item_458 = models.CharField(max_length=8, choices=item_458_choices, null=True)
    item_459_choices = [(u'produces', u'produces')]
    item_459 = models.CharField(max_length=8, choices=item_459_choices, null=True)
    item_460_choices = [(u'produces', u'produces')]
    item_460 = models.CharField(max_length=8, choices=item_460_choices, null=True)
    item_461_choices = [(u'produces', u'produces')]
    item_461 = models.CharField(max_length=8, choices=item_461_choices, null=True)
    item_462_choices = [(u'produces', u'produces')]
    item_462 = models.CharField(max_length=8, choices=item_462_choices, null=True)
    item_463_choices = [(u'produces', u'produces')]
    item_463 = models.CharField(max_length=8, choices=item_463_choices, null=True)
    item_464_choices = [(u'produces', u'produces')]
    item_464 = models.CharField(max_length=8, choices=item_464_choices, null=True)
    item_465_choices = [(u'produces', u'produces')]
    item_465 = models.CharField(max_length=8, choices=item_465_choices, null=True)
    item_466_choices = [(u'produces', u'produces')]
    item_466 = models.CharField(max_length=8, choices=item_466_choices, null=True)
    item_467_choices = [(u'produces', u'produces')]
    item_467 = models.CharField(max_length=8, choices=item_467_choices, null=True)
    item_468_choices = [(u'produces', u'produces')]
    item_468 = models.CharField(max_length=8, choices=item_468_choices, null=True)
    item_469_choices = [(u'produces', u'produces')]
    item_469 = models.CharField(max_length=8, choices=item_469_choices, null=True)
    item_470_choices = [(u'produces', u'produces')]
    item_470 = models.CharField(max_length=8, choices=item_470_choices, null=True)
    item_471_choices = [(u'produces', u'produces')]
    item_471 = models.CharField(max_length=8, choices=item_471_choices, null=True)
    item_472_choices = [(u'produces', u'produces')]
    item_472 = models.CharField(max_length=8, choices=item_472_choices, null=True)
    item_473_choices = [(u'produces', u'produces')]
    item_473 = models.CharField(max_length=8, choices=item_473_choices, null=True)

sublayers = models.ManyToManyField('self', blank=True, null=True, help_text="Select the PARENT layer (which should be checkbox or radio type). Be sure to also check is_sublayer.")
    themes = models.ManyToManyField("Theme", null=True)
    is_sublayer = models.BooleanField(default=False)
    legend = models.CharField(max_length=255, blank=True, null=True, help_text="URL to legend image")
    legend_title = models.CharField(max_length=255, blank=True, null=True)
    legend_subtitle = models.CharField(max_length=255, blank=True, null=True)
    utfurl = models.CharField(max_length=255, blank=True, null=True)
    default_on = models.BooleanField(default=False, help_text="Should layer appear initially on load?")
    
    #tooltip
    description = models.TextField(blank=True, null=True)
    
    #data description (updated fact sheet) (now the Learn pages)
    data_overview = models.TextField(blank=True, null=True)
    data_status = models.CharField(max_length=255, blank=True, null=True)
    data_source = models.CharField(max_length=512, blank=True, null=True)
    data_notes = models.TextField(blank=True, null=True)
    
    #data catalog links    
    bookmark = models.CharField(max_length=755, blank=True, null=True)
    map_tiles = models.CharField(max_length=255, blank=True, null=True)
    kml = models.CharField(max_length=255, blank=True, null=True)
    data_download = models.CharField(max_length=255, blank=True, null=True)
    learn_more = models.CharField(max_length=255, blank=True, null=True)
    metadata = models.CharField(max_length=255, blank=True, null=True)
    fact_sheet = models.CharField(max_length=255, blank=True, null=True)
    source = models.CharField(max_length=512, blank=True, null=True)
    thumbnail = models.URLField(max_length=255, blank=True, null=True)
    
    #geojson javascript attribution
    EVENT_CHOICES = (
        ('click', 'click'),

from __future__ import unicode_literals

from django.db import migrations, models


class Migration(migrations.Migration):

    dependencies = [
        ('activitydb', '0023_tolasites_tola_report_url'),
    ]

    operations = [
        migrations.CreateModel(
            name='LoggedUser',
            fields=[
                ('username', models.CharField(max_length=30, primary_key=True, serialize=False)),
                ('country', models.CharField(max_length=100)),
                ('email', models.CharField(default='user@mercycorps.com', max_length=100)),
            ],

def get_absolute_url(self):
        """Returns the url to access a detail record for this book."""
        return reverse('website:booklets', args=[str(self.slug)])

    def __str__(self):
        return self.title


class UserUploadedBooklet(models.Model):
    """
    This model is for the form that user filled and uploaded website.
    This is temporary form and Admin should validate and upload it in Booklet model.
    """

    title = models.CharField(null=False, blank=False, verbose_name="عنوان", max_length=120)
    field = models.CharField(null=False, blank=False, verbose_name="رشته", max_length=120)
    topic = models.CharField(null=False, blank=False, verbose_name="درس", max_length=120)
    writer = models.CharField(null=False, blank=False, verbose_name="نویسنده", max_length=120)

    # Admin should remove this after manipulating.
    booklet_file = models.FileField(upload_to="website/tmp_booklet_content", null=True, blank=True)

    BOOKLET_STATUS = (
        ('seen', "مشاهده شد"),
        ('pending', "در حال انجام"),
        ('finished', "انجام شد"),
        ('canceled', "لغو شد"),
    )

    status = models.CharField(
        max_length=20,

_('content template'), max_length=250,
        default='zinnia/_entry_detail.html',
        choices=[('zinnia/_entry_detail.html', _('Default template'))] +
        ENTRY_CONTENT_TEMPLATES,
        help_text=_("Template used to display the entry's content."))

    class Meta:
        abstract = True


class DetailTemplateEntry(models.Model):
    """
    Abstract model class to display entries with a
    custom template if needed on the detail page.
    """
    detail_template = models.CharField(
        _('detail template'), max_length=250,
        default='entry_detail.html',
        choices=[('entry_detail.html', _('Default template'))] +
        ENTRY_DETAIL_TEMPLATES,
        help_text=_("Template used to display the entry's detail page."))

    class Meta:
        abstract = True


class AbstractEntry(
        CoreEntry,
        ContentEntry,
        DiscussionsEntry,
        RelatedEntry,
        LeadEntry,

from __future__ import unicode_literals
from django.db import models

class Device(models.Model):
    
    hostname = models.CharField(max_length=30, verbose_name="Hostname")
    ip_address = models.CharField(max_length=16, verbose_name="IP address")
    vendor = models.CharField(max_length=30, verbose_name="Vendor")

operations = [
        migrations.AlterField(
            model_name='farm',
            name='ip',
            field=models.GenericIPAddressField(null=True, editable=False, help_text='The current IP address of this farm'),
        ),
        migrations.AlterField(
            model_name='farm',
            name='layout',
            field=models.SlugField(null=True, choices=[('aisle', 'A collection of aisles'), ('bay', 'A collection of bays'), ('tray', 'A collections of trays')]),
        ),
        migrations.AlterField(
            model_name='farm',
            name='name',
            field=models.CharField(null=True, max_length=100, help_text='Human readable farm name'),
        ),
        migrations.AlterField(
            model_name='farm',
            name='root_server',
            field=models.URLField(default='http://openag.media.mit.edu', null=True, help_text='URL of the root server to which this farm is registered'),
        ),
        migrations.AlterField(
            model_name='farm',
            name='slug',
            field=models.SlugField(null=True, unique=True, blank=True, help_text='Unique farm identifier', max_length=100),
        ),