Source code for

# Copyright 2022 The SQLNet Company GmbH
# This file is licensed under the Elastic License 2.0 (ELv2).
# Refer to the LICENSE.txt file in the root of the repository
# for details.

A container for the placeholders.

from copy import deepcopy
from inspect import cleandoc

from getml.utilities.formatting import _Formatter

from .diagram import _Diagram
from .helpers import _is_typed_list
from .placeholder import Placeholder
from .staging import _make_staging_overview

[docs]class DataModel: """Abstract representation of the relationship between tables. You might also want to refer to :class:``. Args: population (:class:``): The placeholder representing the population table, which defines the `statistical population <>`_ and contains the targets. Examples: This example will construct a data model in which the 'population_table' depends on the 'peripheral_table' via the 'join_key' column. In addition, only those rows in 'peripheral_table' for which 'time_stamp' is smaller or equal to the 'time_stamp' in 'population_table' are considered: .. code-block:: python dm = population_table.to_placeholder("POPULATION") ) dm.add(peripheral_table.to_placeholder("PERIPHERAL")) dm.POPULATION.join( dm.PERIPHERAL, on="join_key", time_stamps="time_stamp" ) If you want to add more than one peripheral table, you can use :func:``: .. code-block:: python dm = population_table.to_placeholder("POPULATION") ) dm.add( PERIPHERAL1=peripheral_table_1, PERIPHERAL2=peripheral_table_2, ) ) If the relationship between two tables is many-to-one or one-to-one you should clearly say so: .. code-block:: python dm.POPULATION.join( dm.PERIPHERAL, on="join_key", time_stamps="time_stamp",, ) Please also refer to :mod:``. If the join keys or time stamps are named differently in the two different tables, use a tuple: .. code-block:: python dm.POPULATION.join( dm.PERIPHERAL, on=("join_key", "other_join_key"), time_stamps=("time_stamp", "other_time_stamp"), ) You can join over more than one join key: .. code-block:: python dm.POPULATION.join( dm.PERIPHERAL, on=["join_key1", "join_key2", ("join_key3", "other_join_key3")], time_stamps="time_stamp", ) You can also limit the scope of your joins using *memory*. This can significantly speed up training time. For instance, if you only want to consider data from the last seven days, you could do something like this: .. code-block:: python dm.POPULATION.join( dm.PERIPHERAL, on="join_key", time_stamps="time_stamp",, ) In some use cases, particularly those involving time series, it might be a good idea to use targets from the past. You can activate this using *lagged_targets*. But if you do that, you must also define a prediction *horizon*. For instance, if you want to predict data for the next hour, using data from the last seven days, you could do this: .. code-block:: python dm.POPULATION.join( dm.PERIPHERAL, on="join_key", time_stamps="time_stamp", lagged_targets=True,,, ) Please also refer to :mod:``. If the join involves many matches, it might be a good idea to set the relationship to :const:``. This forces the pipeline to always use a propositionalization algorithm for this join, which can significantly speed things up. .. code-block:: python dm.POPULATION.join( dm.PERIPHERAL, on="join_key", time_stamps="time_stamp",, ) Please also refer to :mod:``. In some cases, it is necessary to have more than one placeholder on the same table. This is necessary to create more complicated data models. In this case, you can do something like this: .. code-block:: python dm.add( PERIPHERAL=[peripheral_table]*2, ) ) # We can now access our two placeholders like this: placeholder1 = dm.PERIPHERAL[0] placeholder2 = dm.PERIPHERAL[1] If you want to check out a real-world example where this is necessary, refer to the `CORA notebook <>`_. """ def __init__(self, population): if isinstance(population, str): population = Placeholder(population) if not isinstance(population, Placeholder): raise TypeError( "'population' must be a or a str, got " + type(population).__name__ + "." ) self.population = population self.peripheral = {} def _add(self, placeholder): if in self.peripheral: try: self.peripheral[].append(placeholder) except AttributeError: self.peripheral[] = [ self.peripheral[], placeholder, ] else: self.peripheral.update({ placeholder}) def __dir__(self): attrs = dir(type(self)) + list(vars(self)) attrs.extend(self.names) return attrs def __getattr__(self, key): try: return self[key] except KeyError: super().__getattribute__(key) def __getitem__(self, key): population = vars(self)["population"] peripheral = vars(self)["peripheral"] phs = { "population": population, population, **peripheral, } return phs[key] def _getml_deserialize(self): def deserialize(elem): return ( [e._getml_deserialize() for e in elem] if isinstance(elem, list) else elem._getml_deserialize() ) cmd = self.population._getml_deserialize() cmd["peripheral_"] = {k: deserialize(v) for (k, v) in self.peripheral.items()} return cmd def __iter__(self): yield from [] + ["population"] + list(self.peripheral) def __repr__(self): return "\n\n".join(repr(ph) for ph in self.population.to_list()) def _make_diagram(self): return _Diagram(self.population).to_html() def _make_staging(self): headers = [["data frames", "staging table"]] rows = _make_staging_overview(self.population) staging_table = _Formatter(headers=headers, rows=rows)._render_html() return staging_table def _repr_html_(self): output = cleandoc( f""" <div style='margin-top: 15px; margin-bottom: 5px;'> <div style='margin-bottom: 10px; font-size: 1rem;'>diagram</div> {self._make_diagram()} </div> <div style='margin-top: 15px;'> <div style='margin-bottom: 10px; font-size: 1rem;'>staging</div> {self._make_staging()} </div> """ ) return output
[docs] def add(self, *placeholders): """ Adds peripheral placeholders to the data model. Args: placeholders (:class:``): The placeholder or placeholders you would like to add. """ def to_list(elem): return elem if isinstance(elem, list) else [elem] # We want to be 100% sure that all handles are unique, # so we need deepcopy. placeholders_dc = [ deepcopy(ph) for elem in placeholders for ph in to_list(elem) ] if not _is_typed_list(placeholders_dc, Placeholder): raise TypeError( "'placeholders' must consist of " + "or lists thereof." ) for placeholder in placeholders_dc: self._add(placeholder)
@property def names(self): """ A list of the names of all tables contained in the DataModel. """ return [name for name in self]