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flowmachine.core.join

Class Join

Join(
    left,
    right,
    on_left,
    on_right=None,
    how="inner",
    left_append="",
    right_append="",
)
Source: flowmachine/core/join.py

Class that results when joining two queries. Don't usually call this directly, instead use the join method of query.

Attributes

Parameters

  • left: Query

    Query object to join on.

  • right: Query

    Query object to join on.

  • on_left: list of str, str

    Name of the column on the left table on which to join, if a list will join on the fact that each field is equal

  • on_right: optional, str

    Name of the column on the right table on which to join, if not specified will default to the same as on_left, if a list must be the same length as on_left.

  • how: str, default 'inner'

    The method by which to join. Based on the methods provided by postgres. These can be:'inner', 'left outer', 'right outer' and 'full outer'.

  • left_append: str, default ''

    Text with which to append the columns from the left table. Note that the column given by 'on_left' will not be appended to.

  • right_append: str, default ''

    Text with which to append the columns from the left table.

Note

This is not a full implementation of the postgres join api. It assumes joining by matching columns from table1 and table2. The user can construct more complex custom joins by hand.

Methods

_select_targets

_select_targets
Source: flowmachine/core/join.py

Return a list of the SELECT targets for use in _make_query

Returns

  • typing.List[str]

    List of columns to include

cache

cache
Source: flowmachine/core/query.py

Returns

  • bool

    True is caching is switched on.

column_names

column_names
Source: flowmachine/core/join.py

Returns the column names.

Returns

  • typing.List[str]

    List of the column names of this query.

column_names_as_string_list

column_names_as_string_list
Source: flowmachine/core/query.py

Get the column names as a comma separated list

Returns

  • str

    Comma separated list of column names

dependencies

dependencies
Source: flowmachine/core/query.py

Returns

  • set

    The set of queries which this one is directly dependent on.

fully_qualified_table_name

fully_qualified_table_name
Source: flowmachine/core/query.py

Returns a unique fully qualified name for the query to be stored as under the cache schema, based on a hash of the parameters, class, and subqueries.

Returns

  • str

    String form of the table's fqn

index_cols

index_cols
Source: flowmachine/core/query.py

A list of columns to use as indexes when storing this query.

Returns

  • ixen: list

    By default, returns the location columns if they are present and self.spatial_unit is defined, and the subscriber column.

Examples
daily_location("2016-01-01").index_cols
[['name'], '"subscriber"']

is_stored

is_stored
Source: flowmachine/core/query.py

Returns

  • bool

    True if the table is stored, and False otherwise.

query_id

query_id
Source: flowmachine/core/query.py

Generate a uniquely identifying hash of this query, based on the parameters of it and the subqueries it is composed of.

Returns

  • str

    query_id hash string

query_state

query_state
Source: flowmachine/core/query.py

Return the current query state.

Returns

  • QueryState

    The current query state

query_state_str

query_state_str
Source: flowmachine/core/query.py

Return the current query state as a string

Returns

  • str

    The current query state. The possible values are the ones defined in flowmachine.core.query_state.QueryState.

table_name

table_name
Source: flowmachine/core/query.py

Returns a uniquename for the query to be stored as, based on a hash of the parameters, class, and subqueries.

Returns

  • str

    String form of the table's fqn