The Field class is used to describe the mapping of Model attributes to database columns. Each field type has a corresponding SQL storage class (i.e. varchar, int), and conversion between python data types and underlying storage is handled transparently.

When creating a Model class, fields are defined as class-level attributes. This should look familiar to users of the django framework. Here’s an example:

from peewee import *

class User(Model):
    username = CharField()
    join_date = DateTimeField()
    about_me = TextField()

There is one special type of field, ForeignKeyField, which allows you to expose foreign-key relationships between models in an intuitive way:

class Message(Model):
    user = ForeignKeyField(User, related_name='messages')
    body = TextField()
    send_date = DateTimeField()

This allows you to write code like the following:

>>> print some_message.user.username
Some User

>>> for message in some_user.messages:
...     print message.body
some message
another message
yet another message

Field types table

Parameters accepted by all field types and their default values:

  • null = False – boolean indicating whether null values are allowed to be stored
  • db_index = False – boolean indicating whether to create an index on this column
  • unique = False – boolean indicating whether to create a unique index on this column
  • verbose_name = None – string representing the “user-friendly” name of this field
  • help_text = None – string representing any helpful text for this field
  • db_column = None – string representing the underlying column to use if different, useful for legacy databases
Field Type Sqlite Postgresql MySQL
CharField varchar varchar varchar
TextField text text longtext
DateTimeField datetime timestamp datetime
IntegerField integer integer integer
BooleanField smallint boolean bool
FloatField real real real
DoubleField real double precision double precision
BigIntegerField integer bigint bigint
DecimalField decimal numeric numeric
PrimaryKeyField integer serial integer
ForeignKeyField integer integer integer
DateField date date date
TimeField time time time

Some fields take special parameters...

Field type Special Parameters
CharField max_length
DateTimeField formats
DateField formats
TimeField formats
DecimalField max_digits, decimal_places
ForeignKeyField to, related_name, cascade, extra

Self-referential Foreign Keys

Since the class is not available at the time the field is declared, when creating a self-referential foreign key pass in ‘self’ as the “to” relation:

class Category(Model):
    name = CharField()
    parent = ForeignKeyField('self', related_name='children', null=True)

Implementing Many to Many

Peewee does not provide a “field” for many to many relationships the way that django does – this is because the “field” really is hiding an intermediary table. To implement many-to-many with peewee, you will therefore create the intermediary table yourself and query through it:

class Student(Model):
    name = CharField()

class Course(Model):
    name = CharField()

class StudentCourse(Model):
    student = ForeignKeyField(Student)
    course = ForeignKeyField(Course)

To query, let’s say we want to find students who are enrolled in math class:

for student in'math'):

You could also express this as:

for student in Student.filter(studentcourse_set__course__name='math'):

To query what classes a given student is enrolled in:

for course in'da vinci'):

# or, similarly
for course in Course.filter(studentcourse_set__student__name='da vinci'):

Field class API

class Field

The base class from which all other field types extend.

__init__(null=False, db_index=False, unique=False, verbose_name=None, help_text=None, *args, **kwargs)
  • null – this column can accept None or NULL values
  • db_index – create an index for this column when creating the table
  • unique – create a unique index for this column when creating the table
  • verbose_name – specify a “verbose name” for this field, useful for metadata purposes
  • help_text – specify some instruction text for the usage/meaning of this field
Parameters:value – python data type to prep for storage in the database
Return type:converted python datatype
Parameters:value – data coming from the backend storage
Return type:python data type
lookup_value(lookup_type, value)
  • lookup_type – a peewee lookup type, such as ‘eq’ or ‘contains’
  • value – a python data type
Return type:

data type converted for use when querying


Simple hook for Field classes to indicate when the Model class the field exists on has been created.

class CharField

Stores: small strings (0-255 bytes)

class TextField

Stores: arbitrarily large strings

class DateTimeField

Stores: python datetime.datetime instances

Accepts a special parameter formats, which contains a list of formats the datetime can be encoded with. The default behavior is:

'%Y-%m-%d %H:%M:%S.%f' # year-month-day hour-minute-second.microsecond
'%Y-%m-%d %H:%M:%S' # year-month-day hour-minute-second
'%Y-%m-%d' # year-month-day


If the incoming value does not match a format, it will be returned as-is

class DateField

Stores: python instances

Accepts a special parameter formats, which contains a list of formats the date can be encoded with. The default behavior is:

'%Y-%m-%d' # year-month-day
'%Y-%m-%d %H:%M:%S' # year-month-day hour-minute-second
'%Y-%m-%d %H:%M:%S.%f' # year-month-day hour-minute-second.microsecond


If the incoming value does not match a format, it will be returned as-is

class TimeField

Stores: python datetime.time instances

Accepts a special parameter formats, which contains a list of formats the time can be encoded with. The default behavior is:

'%H:%M:%S.%f' # hour:minute:second.microsecond
'%H:%M:%S' # hour:minute:second
'%H:%M' # hour:minute
'%Y-%m-%d %H:%M:%S.%f' # year-month-day hour-minute-second.microsecond
'%Y-%m-%d %H:%M:%S' # year-month-day hour-minute-second


If the incoming value does not match a format, it will be returned as-is

class IntegerField

Stores: integers

class BooleanField

Stores: True / False

class FloatField

Stores: floating-point numbers

class DecimalField

Stores: decimal numbers

class PrimaryKeyField

Stores: auto-incrementing integer fields suitable for use as primary key

class ForeignKeyField

Stores: relationship to another model

__init__(to[, related_name=None[, ...]])
  • to – related Model class or the string ‘self’ if declaring a self-referential foreign key
  • related_name – attribute to expose on related model
class Blog(Model):
    name = CharField()

class Entry(Model):
    blog = ForeignKeyField(Blog, related_name='entries')
    title = CharField()
    content = TextField()

# "blog" attribute
<Blog: My Awesome Blog>

# "entries" related name attribute
>>> for entry in my_awesome_blog.entries:
...     print entry.title
Some entry
Another entry
Yet another entry