150 lines
4.4 KiB
Markdown
150 lines
4.4 KiB
Markdown
# Common Parameters
|
|
|
|
All `Field` types have a set of common parameters.
|
|
|
|
## primary_key
|
|
|
|
`primary_key`: `bool` = `False` -> by default False.
|
|
|
|
Sets the primary key column on a table, foreign keys always refer to the pk of the `Model`.
|
|
|
|
Used in sql only.
|
|
|
|
## autoincrement
|
|
|
|
`autoincrement`: `bool` = `primary_key and type == int` -> defaults to True if column is a primary key and of type Integer, otherwise False.
|
|
|
|
Can be only used with int/bigint fields.
|
|
|
|
If a field has autoincrement it becomes optional.
|
|
|
|
Used both in sql and pydantic (changes pk field to optional for autoincrement).
|
|
|
|
## nullable
|
|
|
|
`nullable`: `bool` = `not primary_key` -> defaults to False for primary key column, and True for all other.
|
|
|
|
Specifies if field is optional or required, used both with sql and pydantic.
|
|
|
|
!!!note
|
|
By default all `ForeignKeys` are also nullable, meaning the related `Model` is not required.
|
|
|
|
If you change the `ForeignKey` column to `nullable=False`, it becomes required.
|
|
|
|
|
|
!!!info
|
|
If you want to know more about how you can preload related models during queries and how the relations work read the [queries][queries] and [relations][relations] sections.
|
|
|
|
|
|
## default
|
|
|
|
`default`: `Any` = `None` -> defaults to None.
|
|
|
|
A default value used if no other value is passed.
|
|
|
|
In sql invoked on an insert, used during pydantic model definition.
|
|
|
|
If the field has a default value it becomes optional.
|
|
|
|
You can pass a static value or a Callable (function etc.)
|
|
|
|
Used both in sql and pydantic.
|
|
|
|
Sample usage:
|
|
|
|
```python
|
|
# note the distinction between passing a value and Callable pointer
|
|
|
|
# value
|
|
name: str = ormar.String(max_length=200, default="Name")
|
|
|
|
# note that when you call a function it's not a pointer to Callable
|
|
# a definition like this will call the function at startup and assign
|
|
# the result of the function to the default, so it will be constant value for all instances
|
|
created_date: datetime.datetime = ormar.DateTime(default=datetime.datetime.now())
|
|
|
|
# if you want to pass Callable reference (note that it cannot have arguments)
|
|
# note lack of the parenthesis -> ormar will call this function for you on each model
|
|
created_date: datetime.datetime = ormar.DateTime(default=datetime.datetime.now)
|
|
|
|
# Callable can be a function, builtin, class etc.
|
|
```
|
|
|
|
## server default
|
|
|
|
`server_default`: `Any` = `None` -> defaults to None.
|
|
|
|
A default value used if no other value is passed.
|
|
|
|
In sql invoked on the server side so you can pass i.e. sql function (like now() or query/value wrapped in sqlalchemy text() clause).
|
|
|
|
If the field has a server_default value it becomes optional.
|
|
|
|
You can pass a static value or a Callable (function etc.)
|
|
|
|
Used in sql only.
|
|
|
|
Sample usage:
|
|
|
|
```Python hl_lines="21-23"
|
|
--8<-- "../docs_src/fields/docs004.py"
|
|
```
|
|
|
|
!!!warning
|
|
`server_default` accepts `str`, `sqlalchemy.sql.elements.ClauseElement` or `sqlalchemy.sql.elements.TextClause`
|
|
so if you want to set i.e. Integer value you need to wrap it in `sqlalchemy.text()` function like above
|
|
|
|
!!!tip
|
|
You can pass also valid sql (dialect specific) wrapped in `sqlalchemy.text()`
|
|
|
|
For example `func.now()` above could be exchanged for `text('(CURRENT_TIMESTAMP)')` for sqlite backend
|
|
|
|
!!!info
|
|
`server_default` is passed straight to sqlalchemy table definition so you can read more in [server default][server default] sqlalchemy documentation
|
|
|
|
## index
|
|
|
|
`index`: `bool` = `False` -> by default False,
|
|
|
|
Sets the index on a table's column.
|
|
|
|
Used in sql only.
|
|
|
|
## unique
|
|
|
|
`unique`: `bool` = `False`
|
|
|
|
Sets the unique constraint on a table's column.
|
|
|
|
Used in sql only.
|
|
|
|
## pydantic_only (**DEPRECATED**)
|
|
|
|
**This parameter is deprecated and will be removed in one of next releases!**
|
|
|
|
**To check how to declare pydantic only fields that are not saved into database see [pydantic fields section](pydantic-fields.md)**
|
|
|
|
`pydantic_only`: `bool` = `False`
|
|
|
|
Prevents creation of a sql column for given field.
|
|
|
|
Used for data related to given model but not to be stored in the database.
|
|
|
|
Used in pydantic only.
|
|
|
|
## choices
|
|
|
|
`choices`: `Sequence` = `[]`
|
|
|
|
A set of choices allowed to be used for given field.
|
|
|
|
Used for data validation on pydantic side.
|
|
|
|
Prevents insertion of value not present in the choices list.
|
|
|
|
Used in pydantic only.
|
|
|
|
[relations]: ../relations/index.md
|
|
[queries]: ../queries/index.md
|
|
[pydantic]: https://pydantic-docs.helpmanual.io/usage/types/#constrained-types
|
|
[server default]: https://docs.sqlalchemy.org/en/13/core/defaults.html#server-invoked-ddl-explicit-default-expressions |