pyaccesskit.schema.columns¶

pyaccesskit.schema.columns ¶

Column (field) specifications and the :class:Column factory.

Each Access data type has its own immutable spec class (TextColumn, NumberColumn...) so that only options meaningful for that type are accepted. The classes form a discriminated union on type (:data:ColumnSpec), which is also how columns appear in JSON/YAML::

{"type": "text", "name": "Email", "length": 255}

Most code uses the :class:Column factory, which mirrors the Access table designer::

Column.autonumber("CustomerID", primary_key=True)
Column.text("CustomerName", length=200, required=True)
Column.number("Quantity", size=NumberSize.INTEGER)
Column.currency("UnitPrice", default=0)

ColumnSpec `module-attribute` ¶

ColumnSpec = Annotated[
    TextColumn
    | LongTextColumn
    | NumberColumn
    | DecimalColumn
    | CurrencyColumn
    | AutoNumberColumn
    | DateTimeColumn
    | YesNoColumn
    | HyperlinkColumn
    | OleObjectColumn
    | UnsupportedColumn,
    Field(discriminator="type"),
]

Any column spec (a Pydantic discriminated union on type).

ColumnBase ¶

Bases: SpecModel

Options shared by every column type.

Attributes:

Name	Type	Description
`name`	`str`	Field name (≤64 characters; see Access naming rules).
`required`	`bool`	Disallow Null values (Required property).
`default`	`DefaultValue \| None`	Default value: a Python literal (rendered as an Access literal) or an `Expr`.
`validation_rule`	`str \| None`	Validation Rule expression, e.g. `">0"`.
`validation_text`	`str \| None`	Message shown when the validation rule fails.
`description`	`str \| None`	Description shown in the table designer.
`caption`	`str \| None`	Caption used as the default label text on forms and datasheet headers.
`format`	`str \| None`	Format property, e.g. `"Short Date"` or `"Currency"`.
`primary_key`	`bool`	Shorthand: include this column in the table's primary key.
`unique`	`bool`	Shorthand: create a unique single-column index named after the column.
`indexed`	`bool`	Shorthand: create a non-unique single-column index named after the column.
`properties`	`dict[str, PropertyValue]`	Other Access/DAO field properties to set verbatim (escape hatch).

normalized ¶

normalized() -> Self

Canonical form: the index shorthands are cleared (they live in TableSpec.indexes).

TextColumn ¶

Bases: ColumnBase

Short Text: up to 255 characters.

LongTextColumn ¶

Bases: ColumnBase

Long Text (Memo): up to ~1 GB; optionally rich text and append-only.

HyperlinkColumn ¶

Bases: ColumnBase

Hyperlink: a Long Text field flagged as a hyperlink.

NumberColumn ¶

Bases: ColumnBase

Number with a Field Size of Byte, Integer (16-bit), Long Integer, Single, Double or Replication ID.

decimal_places `class-attribute` `instance-attribute` ¶

decimal_places: int | None = Field(
    default=None, ge=0, le=15
)

None means Auto.

DecimalColumn ¶

Bases: ColumnBase

Number with Field Size = Decimal (exact, with precision and scale).

CurrencyColumn ¶

Bases: ColumnBase

Currency: fixed-point, 4 decimal places, no rounding surprises.

AutoNumberColumn ¶

Bases: ColumnBase

AutoNumber: an incrementing Long Integer, or a Replication ID (GUID).

Random AutoNumbers are not offered: DAO silently ignores the setting, so PyAccessKit cannot create them reliably (see ADR 0002).

DateTimeColumn ¶

Bases: ColumnBase

Date/Time.

YesNoColumn ¶

Bases: ColumnBase

Yes/No (Boolean). Shown as a check box in datasheets and bound forms.

OleObjectColumn ¶

Bases: ColumnBase

OLE Object (long binary data).

UnsupportedColumn ¶

Bases: ColumnBase

A column PyAccessKit can read but not create yet (Attachment, Calculated, Large Number...).

It appears when introspecting existing databases so that to_spec() never fails; creating a table with one raises :class:~pyaccesskit.errors.SpecError.

ColumnOptions ¶

Bases: TypedDict

Keyword options accepted by every :class:Column constructor (see :class:ColumnBase).

AutoNumberOptions ¶

Bases: TypedDict

Keyword options accepted by :meth:Column.autonumber (no default/required).

OleObjectOptions ¶

Bases: AutoNumberOptions

Keyword options accepted by :meth:Column.ole_object (no default value).

Column ¶

Column()

Factory for column specs, mirroring the data types of the Access table designer.

Every constructor raises :class:~pyaccesskit.errors.SpecError for invalid options.

text `staticmethod` ¶

text(
    name: str,
    *,
    length: int = 255,
    allow_zero_length: bool = False,
    unicode_compression: bool = True,
    input_mask: str | None = None,
    **options: Unpack[ColumnOptions],
) -> TextColumn

Short Text (length 1-255, default 255).

long_text `staticmethod` ¶

long_text(
    name: str,
    *,
    rich_text: bool = False,
    append_only: bool = False,
    allow_zero_length: bool = False,
    unicode_compression: bool = True,
    **options: Unpack[ColumnOptions],
) -> LongTextColumn

Long Text (Memo).

number `staticmethod` ¶

number(
    name: str,
    *,
    size: NumberSize | str = NumberSize.LONG_INTEGER,
    decimal_places: int | None = None,
    input_mask: str | None = None,
    **options: Unpack[ColumnOptions],
) -> NumberColumn

Number. size defaults to Long Integer (32-bit), exactly like Access.

decimal `staticmethod` ¶

decimal(
    name: str,
    *,
    precision: int = 18,
    scale: int = 0,
    decimal_places: int | None = None,
    input_mask: str | None = None,
    **options: Unpack[ColumnOptions],
) -> DecimalColumn

Number with Field Size = Decimal(precision, scale).

currency `staticmethod` ¶

currency(
    name: str,
    *,
    decimal_places: int | None = None,
    input_mask: str | None = None,
    **options: Unpack[ColumnOptions],
) -> CurrencyColumn

Currency.

autonumber `staticmethod` ¶

autonumber(
    name: str,
    *,
    replication_id: bool = False,
    **options: Unpack[AutoNumberOptions],
) -> AutoNumberColumn

AutoNumber (Long Integer by default; replication_id=True for a GUID).

date_time `staticmethod` ¶

date_time(
    name: str,
    *,
    input_mask: str | None = None,
    **options: Unpack[ColumnOptions],
) -> DateTimeColumn

Date/Time.

yes_no `staticmethod` ¶

yes_no(
    name: str, **options: Unpack[ColumnOptions]
) -> YesNoColumn

Yes/No (Boolean).

hyperlink `staticmethod` ¶

hyperlink(
    name: str,
    *,
    allow_zero_length: bool = False,
    unicode_compression: bool = True,
    **options: Unpack[ColumnOptions],
) -> HyperlinkColumn

Hyperlink.

ole_object `staticmethod` ¶

ole_object(
    name: str, **options: Unpack[OleObjectOptions]
) -> OleObjectColumn

OLE Object (long binary).

pyaccesskit.schema.columns¶