pudl.metadata.resources

A subpackage to define and organize PUDL database tables by data group.

Submodules

Package Contents

Functions

build_foreign_keys(resources: Dict[str, dict], prune: bool = True) → Dict[str, List[dict]]

Build foreign keys for each resource.

Attributes

RESOURCE_METADATA

module

FOREIGN_KEYS

Generated foreign key constraints by resource name.
pudl.metadata.resources.build_foreign_keys(resources: Dict[str, dict], prune: bool = True) → Dict[str, List[dict]][source]

Build foreign keys for each resource.

A resource’s foreign_key_rules (if present) determines which other resources will be assigned a foreign key (foreign_keys) to the reference’s primary key:

  • fields (List[List[str]]): Sets of field names for which to create a foreign key. These are assumed to match the order of the reference’s primary key fields.

  • exclude (Optional[List[str]]): Names of resources to exclude.

Parameters

  • resources – Resource descriptors by name.

  • prune – Whether to prune redundant foreign keys.

Returns

Foreign keys for each resource (if any), by resource name.

  • fields (List[str]): Field names.

  • reference[‘resource’] (str): Reference resource name.

  • reference[‘fields’] (List[str]): Reference resource field names.

Examples

>>> resources = {
...     'x': {
...         'schema': {
...             'fields': ['z'],
...             'primary_key': ['z'],
...             'foreign_key_rules': {'fields': [['z']]}
...         }
...     },
...     'y': {
...         'schema': {
...             'fields': ['z', 'yy'],
...             'primary_key': ['z', 'yy'],
...             'foreign_key_rules': {'fields': [['z', 'zz']]}
...         }
...     },
...     'z': {'schema': {'fields': ['z', 'zz']}}
... }
>>> keys = build_foreign_keys(resources)
>>> keys['z']
[{'fields': ['z', 'zz'], 'reference': {'resource': 'y', 'fields': ['z', 'yy']}}]
>>> keys['y']
[{'fields': ['z'], 'reference': {'resource': 'x', 'fields': ['z']}}]
>>> keys = build_foreign_keys(resources, prune=False)
>>> keys['z'][0]
{'fields': ['z'], 'reference': {'resource': 'x', 'fields': ['z']}}
pudl.metadata.resources.RESOURCE_METADATA[source]
pudl.metadata.resources.module[source]
pudl.metadata.resources.FOREIGN_KEYS :Dict[str, List[dict]][source]

Generated foreign key constraints by resource name.

See pudl.metadata.helpers.build_foreign_keys().