# Django 2.2.9.dev20191202104323 文档

# PostgreSQL specific form fields and widgets

All of these fields and widgets are available from the `django.contrib.postgres.forms` module.

## 字段

### `SimpleArrayField`

class `SimpleArrayField`(base_field, delimiter=', ', max_length=None, min_length=None)

  A simple field which maps to an array. It is represented by an HTML `<input>`.

  `base_field`

    This is a required argument.

    It specifies the underlying form field for the array. This is not used to render any HTML, but it is used to process the submitted data and validate it. For example:

        >>> from django import forms
        >>> from django.contrib.postgres.forms import SimpleArrayField

        >>> class NumberListForm(forms.Form):
        ...     numbers = SimpleArrayField(forms.IntegerField())

        >>> form = NumberListForm({'numbers': '1,2,3'})
        >>> form.is_valid()
        True
        >>> form.cleaned_data
        {'numbers': [1, 2, 3]}

        >>> form = NumberListForm({'numbers': '1,2,a'})
        >>> form.is_valid()
        False

  `delimiter`

    This is an optional argument which defaults to a comma: `,`. This value is used to split the submitted data. It allows you to chain `SimpleArrayField` for multidimensional data:

        >>> from django import forms
        >>> from django.contrib.postgres.forms import SimpleArrayField

        >>> class GridForm(forms.Form):
        ...     places = SimpleArrayField(SimpleArrayField(IntegerField()), delimiter='|')

        >>> form = GridForm({'places': '1,2|2,1|4,3'})
        >>> form.is_valid()
        True
        >>> form.cleaned_data
        {'places': [[1, 2], [2, 1], [4, 3]]}

    注解

    The field does not support escaping of the delimiter, so be careful in cases where the delimiter is a valid character in the underlying field. The delimiter does not need to be only one character.

  `max_length`

    This is an optional argument which validates that the array does not exceed the stated length.

  `min_length`

    This is an optional argument which validates that the array reaches at least the stated length.

  User friendly forms

  `SimpleArrayField` is not particularly user friendly in most cases, however it is a useful way to format data from a client-side widget for submission to the server.

### `SplitArrayField`

class `SplitArrayField`(base_field, size, remove_trailing_nulls=False)

  This field handles arrays by reproducing the underlying field a fixed number of times.

  `base_field`

    This is a required argument. It specifies the form field to be repeated.

  `size`

    This is the fixed number of times the underlying field will be used.

  `remove_trailing_nulls`

    By default, this is set to `False`. When `False`, each value from the repeated fields is stored. When set to `True`, any trailing values which are blank will be stripped from the result. If the underlying field has `required=True`, but `remove_trailing_nulls` is `True`, then null values are only allowed at the end, and will be stripped.

    Some examples:

        SplitArrayField(IntegerField(required=True), size=3, remove_trailing_nulls=False)

        ['1', '2', '3']  # -> [1, 2, 3]
        ['1', '2', '']  # -> ValidationError - third entry required.
        ['1', '', '3']  # -> ValidationError - second entry required.
        ['', '2', '']  # -> ValidationError - first and third entries required.

        SplitArrayField(IntegerField(required=False), size=3, remove_trailing_nulls=False)

        ['1', '2', '3']  # -> [1, 2, 3]
        ['1', '2', '']  # -> [1, 2, None]
        ['1', '', '3']  # -> [1, None, 3]
        ['', '2', '']  # -> [None, 2, None]

        SplitArrayField(IntegerField(required=True), size=3, remove_trailing_nulls=True)

        ['1', '2', '3']  # -> [1, 2, 3]
        ['1', '2', '']  # -> [1, 2]
        ['1', '', '3']  # -> ValidationError - second entry required.
        ['', '2', '']  # -> ValidationError - first entry required.

        SplitArrayField(IntegerField(required=False), size=3, remove_trailing_nulls=True)

        ['1', '2', '3']  # -> [1, 2, 3]
        ['1', '2', '']  # -> [1, 2]
        ['1', '', '3']  # -> [1, None, 3]
        ['', '2', '']  # -> [None, 2]

### `HStoreField`

class `HStoreField`

  A field which accepts JSON encoded data for an `HStoreField`. It casts all values (except nulls) to strings. It is represented by an HTML `<textarea>`.

  User friendly forms

  `HStoreField` is not particularly user friendly in most cases, however it is a useful way to format data from a client-side widget for submission to the server.

  注解

  On occasions it may be useful to require or restrict the keys which are valid for a given field. This can be done using the `KeysValidator`.

### `JSONField`

class `JSONField`

  A field which accepts JSON encoded data for a `JSONField`. It is represented by an HTML `<textarea>`.

  User friendly forms

  `JSONField` is not particularly user friendly in most cases, however it is a useful way to format data from a client-side widget for submission to the server.

### Range Fields

This group of fields all share similar functionality for accepting range data. They are based on `MultiValueField`. They treat one omitted value as an unbounded range. They also validate that the lower bound is not greater than the upper bound. All of these fields use `RangeWidget`.

#### `IntegerRangeField`

class `IntegerRangeField`

  Based on `IntegerField` and translates its input into `NumericRange`. Default for `IntegerRangeField` and `BigIntegerRangeField`.

#### `DecimalRangeField`

class `DecimalRangeField`
  New in Django 2.2.

  Based on `DecimalField` and translates its input into `NumericRange`. Default for `DecimalRangeField`.

#### `FloatRangeField`

class `FloatRangeField`

  Based on `FloatField` and translates its input into `NumericRange`. Default for `FloatRangeField`.

  2.2 版后已移除: Use `DecimalRangeField` instead.

#### `DateTimeRangeField`

class `DateTimeRangeField`

  Based on `DateTimeField` and translates its input into `DateTimeTZRange`. Default for `DateTimeRangeField`.

#### `DateRangeField`

class `DateRangeField`

  Based on `DateField` and translates its input into `DateRange`. Default for `DateRangeField`.

## 小部件

### `RangeWidget`

class `RangeWidget`(base_widget, attrs=None)

  Widget used by all of the range fields. Based on `MultiWidget`.

  `RangeWidget` has one required argument:

  `base_widget`

    A `RangeWidget` comprises a 2-tuple of `base_widget`.

  `decompress`(value)

    Takes a single "compressed" value of a field, for example a `DateRangeField`, and returns a tuple representing and lower and upper bound.