API Reference¶
datalite Module¶
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@datalite.datalite(db_path: str, type_overload: Optional[Dict[Optional[type], str]] = None) → Callable¶ Bind a dataclass to a sqlite3 database. This adds new methods to the class, such as create_entry(), remove_entry() and update_entry().
- Parameters
db_path – Path of the database to be binded.
type_overload – Type overload dictionary.
- Returns
The new dataclass.
datalite.constraints module¶
- datalite.constraints module introduces constraint
types that can be used to hint field variables, that can be used to signal datalite decorator constraints in the database.
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exception
datalite.constraints.ConstraintFailedError¶ Bases:
ExceptionThis exception is raised when a Constraint fails.
datalite.fetch module¶
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datalite.fetch.fetch_all(class_: type, page: int = 0, element_count: int = 10) → tuple¶ Fetchall the records in the bound database.
- Parameters
class – Class of the records.
page – Which page to retrieve, default all. (0 means closed).
element_count – Element count in each page.
- Returns
All the records of type class_ in the bound database as a tuple.
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datalite.fetch.fetch_equals(class_: type, field: str, value: Any) → Any¶ Fetch a class_ type variable from its bound db.
- Parameters
class – Class to fetch.
field – Field to check for, by default, object id.
value – Value of the field to check for.
- Returns
The object whose data is taken from the database.
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datalite.fetch.fetch_from(class_: type, obj_id: int) → Any¶ Fetch a class_ type variable from its bound dv.
- Parameters
class – Class to fetch from.
obj_id – Unique object id of the object.
- Returns
The fetched object.
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datalite.fetch.fetch_if(class_: type, condition: str, page: int = 0, element_count: int = 10) → tuple¶ Fetch all class_ type variables from the bound db, provided they fit the given condition
- Parameters
class – Class type to fetch.
condition – Condition to check for.
page – Which page to retrieve, default all. (0 means closed).
element_count – Element count in each page.
- Returns
A tuple of records that fit the given condition of given type class_.
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datalite.fetch.fetch_range(class_: type, range_: range) → tuple¶ Fetch the records in a given range of object ids.
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datalite.fetch.fetch_where(class_: type, field: str, value: Any, page: int = 0, element_count: int = 10) → tuple¶ Fetch all class_ type variables from the bound db, provided that the field of the records fit the given value.
- Parameters
class – Class of the records.
field – Field to check.
value – Value to check for.
page – Which page to retrieve, default all. (0 means closed).
element_count – Element count in each page.
- Returns
A tuple of the records.
datalite.mass_actions module¶
This module includes functions to insert multiple records to a bound database at one time, with one time open and closing of the database file.
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exception
datalite.mass_actions.HeterogeneousCollectionError¶ Bases:
Exception- :raiseif the passed collection is not homogeneous.
ie: If a List or Tuple has elements of multiple types.
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datalite.mass_actions.copy_many(objects: Union[List[T], Tuple[T]], db_name: str, protect_memory: bool = True) → None¶ Copy many records to another database, from their original database to new database, do not delete old records.
- Parameters
objects – Objects to copy.
db_name – Name of the new database.
protect_memory – Wheter to protect memory during operation, Setting this to False will quicken the operation, but if the operation is cut short, database file will corrupt.
- Returns
None
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datalite.mass_actions.create_many(objects: Union[List[T], Tuple[T]], protect_memory: bool = True) → None¶ Insert many records corresponding to objects in a tuple or a list.
- Parameters
protect_memory – If False, memory protections are turned off, makes it faster.
objects – A tuple or a list of objects decorated with datalite.
- Returns
None.
datalite.migrations module¶
Migrations module deals with migrating data when the object definitions change. This functions deal with Schema Migrations.
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datalite.migrations.basic_migrate(class_: type, column_transfer: dict = None) → None¶ Given a class, compare its previous table, delete the fields that no longer exist, create new columns for new fields. If the column_flow parameter is given, migrate elements from previous column to the new ones. It should be noted that, the obj_ids do not persist.
- Parameters
class – Datalite class to migrate.
column_transfer – A dictionary showing which columns will be copied to new ones.
- Returns
None.