Django1.5 model字段类型清单
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之前看到一篇文章对Django model类型清单的说明,原文地址:http://www.cnblogs.com/lhj588/archive/2012/05/24/2516040.html
翻看django1.5的文档,发现这份清单已经过时,把django1.5的field type贴出来供查阅。原地址为:https://docs.djangoproject.com/en/dev/ref/models/fields/#field-types
Field types
AutoField
- class AutoField(**options)
An IntegerField that automatically increments according to available IDs. You usually won’t need to use this directly; a primary key field will automatically be added to your model if you don’t specify otherwise. See Automatic primary key fields.
BigIntegerField
- class BigIntegerField([**options])
A 64 bit integer, much like an IntegerField except that it is guaranteed to fit numbers from -9223372036854775808 to 9223372036854775807. The default form widget for this field is a TextInput.
BinaryField
- class BinaryField([**options])
A field to store raw binary data. It only supports bytes assignment. Be aware that this field has limited functionality. For example, it is not possible to filter a queryset on a BinaryField value.
Abusing BinaryField
Although you might think about storing files in the database, consider that it is bad design in 99% of the cases. This field is not a replacement for proper static files handling.
BooleanField
- class BooleanField(**options)
A true/false field.
The default form widget for this field is a CheckboxInput.
If you need to accept null values then use NullBooleanField instead.
The default value of BooleanField was changed from False to None when Field.default isn’t defined.
CharField
- class CharField(max_length=None[, **options])
A string field, for small- to large-sized strings.
For large amounts of text, use TextField.
The default form widget for this field is a TextInput.
CharField has one extra required argument:
- CharField.max_length
The maximum length (in characters) of the field. The max_length is enforced at the database level and in Django’s validation.
Note
If you are writing an application that must be portable to multiple database backends, you should be aware that there are restrictions on max_length for some backends. Refer to the database backend notes for details.
MySQL users
If you are using this field with MySQLdb 1.2.2 and the utf8_bin collation (which is not the default), there are some issues to be aware of. Refer to the MySQL database notes for details.
CommaSeparatedIntegerField
- class CommaSeparatedIntegerField(max_length=None[, **options])
A field of integers separated by commas. As in CharField, the max_length argument is required and the note about database portability mentioned there should be heeded.
DateField
- class DateField([auto_now=False, auto_now_add=False, **options])
A date, represented in Python by a datetime.date instance. Has a few extra, optional arguments:
- DateField.auto_now
Automatically set the field to now every time the object is saved. Useful for “last-modified” timestamps. Note that the current date is always used; it’s not just a default value that you can override.
- DateField.auto_now_add
Automatically set the field to now when the object is first created. Useful for creation of timestamps. Note that the current date is always used; it’s not just a default value that you can override.
The default form widget for this field is a TextInput. The admin adds a JavaScript calendar, and a shortcut for “Today”. Includes an additional invalid_date error message key.
Note
As currently implemented, setting auto_now or auto_now_add to True will cause the field to have editable=False andblank=True set.
DateTimeField
- class DateTimeField([auto_now=False, auto_now_add=False, **options])
A date and time, represented in Python by a datetime.datetime instance. Takes the same extra arguments as DateField.
The default form widget for this field is a single TextInput. The admin uses two separate TextInput widgets with JavaScript shortcuts.
DecimalField
- class DecimalField(max_digits=None, decimal_places=None[, **options])
A fixed-precision decimal number, represented in Python by a Decimal instance. Has two required arguments:
- DecimalField.max_digits
The maximum number of digits allowed in the number. Note that this number must be greater than or equal todecimal_places.
- DecimalField.decimal_places
The number of decimal places to store with the number.
For example, to store numbers up to 999 with a resolution of 2 decimal places, you’d use:
models.DecimalField(..., max_digits=5, decimal_places=2)
And to store numbers up to approximately one billion with a resolution of 10 decimal places:
models.DecimalField(..., max_digits=19, decimal_places=10)
The default form widget for this field is a TextInput.
Note
For more information about the differences between the FloatField and DecimalField classes, please see FloatField vs. DecimalField.
EmailField
- class EmailField([max_length=75, **options])
A CharField that checks that the value is a valid email address.
Incompliance to RFCs
The default 75 character max_length is not capable of storing all possible RFC3696/5321-compliant email addresses. In order to store all possible valid email addresses, a max_length of 254 is required. The defaultmax_length of 75 exists for historical reasons. The default has not been changed in order to maintain backwards compatibility with existing uses of EmailField.
FileField
- class FileField(upload_to=None[, max_length=100, **options])
A file-upload field.
Note
The primary_key and unique arguments are not supported, and will raise a TypeError if used.
Has one required argument:
- FileField.upload_to
A local filesystem path that will be appended to your MEDIA_ROOT setting to determine the value of the url attribute.
This path may contain strftime() formatting, which will be replaced by the date/time of the file upload (so that uploaded files don’t fill up the given directory).
This may also be a callable, such as a function, which will be called to obtain the upload path, including the filename. This callable must be able to accept two arguments, and return a Unix-style path (with forward slashes) to be passed along to the storage system. The two arguments that will be passed are:
Argument Description instanceAn instance of the model where the FileField is defined. More specifically, this is the particular instance where the current file is being attached.
In most cases, this object will not have been saved to the database yet, so if it uses the default AutoField, it might not yet have a value for its primary key field.
filenameThe filename that was originally given to the file. This may or may not be taken into account when determining the final destination path.
Also has one optional argument:
- FileField.storage
Optional. A storage object, which handles the storage and retrieval of your files. See Managing files for details on how to provide this object.
The default form widget for this field is a FileInput.
Using a FileField or an ImageField (see below) in a model takes a few steps:
- In your settings file, you’ll need to define MEDIA_ROOT as the full path to a directory where you’d like Django to store uploaded files. (For performance, these files are not stored in the database.) Define MEDIA_URL as the base public URL of that directory. Make sure that this directory is writable by the Web server’s user account.
- Add the FileField or ImageField to your model, making sure to define the upload_to option to tell Django to which subdirectory of MEDIA_ROOT it should upload files.
- All that will be stored in your database is a path to the file (relative to MEDIA_ROOT). You’ll most likely want to use the convenience url attribute provided by Django. For example, if your ImageField is called mug_shot, you can get the absolute path to your image in a template with {{ object.mug_shot.url }}.
For example, say your MEDIA_ROOT is set to '/home/media', and upload_to is set to 'photos/%Y/%m/%d'. The '%Y/%m/%d' part of upload_tois strftime() formatting; '%Y' is the four-digit year, '%m' is the two-digit month and '%d' is the two-digit day. If you upload a file on Jan. 15, 2007, it will be saved in the directory /home/media/photos/2007/01/15.
If you wanted to retrieve the uploaded file’s on-disk filename, or the file’s size, you could use the name and size attributes respectively; for more information on the available attributes and methods, see the File class reference and the Managing files topic guide.
Note
The file is saved as part of saving the model in the database, so the actual file name used on disk cannot be relied on until after the model has been saved.
The uploaded file’s relative URL can be obtained using the url attribute. Internally, this calls the url() method of the underlying Storage class.
Note that whenever you deal with uploaded files, you should pay close attention to where you’re uploading them and what type of files they are, to avoid security holes. Validate all uploaded files so that you’re sure the files are what you think they are. For example, if you blindly let somebody upload files, without validation, to a directory that’s within your Web server’s document root, then somebody could upload a CGI or PHP script and execute that script by visiting its URL on your site. Don’t allow that.
Also note that even an uploaded HTML file, since it can be executed by the browser (though not by the server), can pose security threats that are equivalent to XSS or CSRF attacks.
By default, FileField instances are created as varchar(100) columns in your database. As with other fields, you can change the maximum length using the max_length argument.
FileField and FieldFile
- class FieldFile
When you access a FileField on a model, you are given an instance of FieldFile as a proxy for accessing the underlying file. This class has several attributes and methods that can be used to interact with file data:
- FieldFile.url
A read-only property to access the file’s relative URL by calling the url() method of the underlying Storage class.
- FieldFile.open(mode='rb')
Behaves like the standard Python open() method and opens the file associated with this instance in the mode specified bymode.
- FieldFile.close()
Behaves like the standard Python file.close() method and closes the file associated with this instance.
- FieldFile.save(name, content, save=True)
This method takes a filename and file contents and passes them to the storage class for the field, then associates the stored file with the model field. If you want to manually associate file data with FileField instances on your model, the save() method is used to persist that file data.
Takes two required arguments: name which is the name of the file, and content which is an object containing the file’s contents. The optional save argument controls whether or not the instance is saved after the file has been altered. Defaults to True.
Note that the content argument should be an instance of django.core.files.File, not Python’s built-in file object. You can construct a File from an existing Python file object like this:
from django.core.files import File# Open an existing file using Python's built-in open()f = open('/tmp/hello.world')myfile = File(f)
Or you can construct one from a Python string like this:
from django.core.files.base import ContentFilemyfile = ContentFile("hello world")
For more information, see Managing files.
- FieldFile.delete(save=True)
Deletes the file associated with this instance and clears all attributes on the field. Note: This method will close the file if it happens to be open when delete() is called.
The optional save argument controls whether or not the instance is saved after the file has been deleted. Defaults to True.
Note that when a model is deleted, related files are not deleted. If you need to cleanup orphaned files, you’ll need to handle it yourself (for instance, with a custom management command that can be run manually or scheduled to run periodically via e.g. cron).
FilePathField
- class FilePathField(path=None[, match=None, recursive=False, max_length=100, **options])
A CharField whose choices are limited to the filenames in a certain directory on the filesystem. Has three special arguments, of which the first is required:
- FilePathField.path
Required. The absolute filesystem path to a directory from which this FilePathField should get its choices. Example:"/home/images".
- FilePathField.match
Optional. A regular expression, as a string, that FilePathField will use to filter filenames. Note that the regex will be applied to the base filename, not the full path. Example: "foo.*\.txt$", which will match a file called foo23.txt but not bar.txt orfoo23.png.
- FilePathField.recursive
Optional. Either True or False. Default is False. Specifies whether all subdirectories of path should be included
- FilePathField.allow_files
- New in Django 1.5.
Optional. Either True or False. Default is True. Specifies whether files in the specified location should be included. Either this or allow_folders must be True.
- FilePathField.allow_folders
- New in Django 1.5.
Optional. Either True or False. Default is False. Specifies whether folders in the specified location should be included. Either this or allow_files must be True.
Of course, these arguments can be used together.
The one potential gotcha is that match applies to the base filename, not the full path. So, this example:
FilePathField(path="/home/images", match="foo.*", recursive=True)
...will match /home/images/foo.png but not /home/images/foo/bar.png because the match applies to the base filename (foo.png andbar.png).
By default, FilePathField instances are created as varchar(100) columns in your database. As with other fields, you can change the maximum length using the max_length argument.
FloatField
- class FloatField([**options])
A floating-point number represented in Python by a float instance.
The default form widget for this field is a TextInput.
FloatField vs. DecimalField
The FloatField class is sometimes mixed up with the DecimalField class. Although they both represent real numbers, they represent those numbers differently. FloatField uses Python’s float type internally, whileDecimalField uses Python’s Decimal type. For information on the difference between the two, see Python’s documentation for the decimal module.
ImageField
- class ImageField(upload_to=None[, height_field=None, width_field=None, max_length=100, **options])
Inherits all attributes and methods from FileField, but also validates that the uploaded object is a valid image.
In addition to the special attributes that are available for FileField, an ImageField also has height and width attributes.
To facilitate querying on those attributes, ImageField has two extra optional arguments:
- ImageField.height_field
Name of a model field which will be auto-populated with the height of the image each time the model instance is saved.
- ImageField.width_field
Name of a model field which will be auto-populated with the width of the image each time the model instance is saved.
Requires the Python Imaging Library.
By default, ImageField instances are created as varchar(100) columns in your database. As with other fields, you can change the maximum length using the max_length argument.
IntegerField
- class IntegerField([**options])
An integer. The default form widget for this field is a TextInput.
IPAddressField
- class IPAddressField([**options])
An IP address, in string format (e.g. “192.0.2.30”). The default form widget for this field is a TextInput.
GenericIPAddressField
- class GenericIPAddressField([protocol=both, unpack_ipv4=False, **options])
An IPv4 or IPv6 address, in string format (e.g. 192.0.2.30 or 2a02:42fe::4). The default form widget for this field is a TextInput.
The IPv6 address normalization follows RFC 4291 section 2.2, including using the IPv4 format suggested in paragraph 3 of that section, like ::ffff:192.0.2.0. For example, 2001:0::0:01 would be normalized to 2001::1, and ::ffff:0a0a:0a0a to::ffff:10.10.10.10. All characters are converted to lowercase.
- GenericIPAddressField.protocol
Limits valid inputs to the specified protocol. Accepted values are 'both' (default), 'IPv4' or 'IPv6'. Matching is case insensitive.
- GenericIPAddressField.unpack_ipv4
Unpacks IPv4 mapped addresses like ::ffff:192.0.2.1. If this option is enabled that address would be unpacked to192.0.2.1. Default is disabled. Can only be used when protocol is set to 'both'.
NullBooleanField
- class NullBooleanField([**options])
Like a BooleanField, but allows NULL as one of the options. Use this instead of a BooleanField with null=True. The default form widget for this field is a NullBooleanSelect.
PositiveIntegerField
- class PositiveIntegerField([**options])
Like an IntegerField, but must be either positive or zero (0). The value 0 is accepted for backward compatibility reasons.
PositiveSmallIntegerField
- class PositiveSmallIntegerField([**options])
Like a PositiveIntegerField, but only allows values under a certain (database-dependent) point. Values up to 32767 are safe in all databases supported by Django.
SlugField
- class SlugField([max_length=50, **options])
Slug is a newspaper term. A slug is a short label for something, containing only letters, numbers, underscores or hyphens. They’re generally used in URLs.
Like a CharField, you can specify max_length (read the note about database portability and max_length in that section, too). Ifmax_length is not specified, Django will use a default length of 50.
Implies setting Field.db_index to True.
It is often useful to automatically prepopulate a SlugField based on the value of some other value. You can do this automatically in the admin using prepopulated_fields.
SmallIntegerField
- class SmallIntegerField([**options])
Like an IntegerField, but only allows values under a certain (database-dependent) point. Values from -32768 to 32767 are safe in all databases supported by Django.
TextField
- class TextField([**options])
A large text field. The default form widget for this field is a Textarea.
MySQL users
If you are using this field with MySQLdb 1.2.1p2 and the utf8_bin collation (which is not the default), there are some issues to be aware of. Refer to the MySQL database notes for details.
TimeField
- class TimeField([auto_now=False, auto_now_add=False, **options])
A time, represented in Python by a datetime.time instance. Accepts the same auto-population options as DateField.
The default form widget for this field is a TextInput. The admin adds some JavaScript shortcuts.
URLField
- class URLField([max_length=200, **options])
A CharField for a URL.
The default form widget for this field is a TextInput.
Like all CharField subclasses, URLField takes the optional max_length argument. If you don’t specify max_length, a default of 200 is used.
The current value of the field will be displayed as a clickable link above the input widget.
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