New cheat sheet content (#163)

* New cheat sheet content

* Split cheat sheet into multiple pages

source/content/cheatsheet/databases.md

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+## Databases
+
+**Q:** How do I list all databases?
+
+```python
+sorted(bd.databases)
+```
+
+**Q:** How do I test if a given database is installed?
+
+```python
+'<my database label>' in bd.databases
+```
+
+**Q:** How do I instantiate a `Database` object?
+
+```python
+my_db = bd.Database('<database_name>')
+```
+
+**Q:** How do I copy a `Database`?
+
+```python
+copied_database = bd.Database('<database_name>').copy('<new_name>')
+```
+
+**Q:** How do I rename a `Database`?
+
+```python
+new_database = bd.Database('<database_name>').rename('<new_name>')
+```
+
+**Q:** How do I delete a `Database`?
+
+```python
+del bd.databases['<database_name>']
+```
+
+### Metadata
+
+**Q:** How do I see the `Database` metadata?
+
+```python
+bd.Database('<database_name>').metadata
+```
+
+**Q:** How do I change the `Database` metadata?
+
+```python
+bd.Database('<database_name>').metadata['<some_key>'] = '<some_value>'
+```
+
+**Q:** How do I see which other databases this `Database` refers to?
+
+```python
+bd.Database('<database_name>').metadata['depends']
+```
+
+**Q:** How can I see what kind of modelling paradigm and storage engine a `Database` uses?
+
+This information is given to a limited degree by the database backend:
+
+```python
+bd.Database('<database_name>').metadata['backend']
+```
+
+There are three backends in a normal Brightway installation:
+
+* `sqlite`: The default backend. Uses SQLite like a graph database.
+* `iotable`: Uses the SQLite database for nodes, but stores edges only in datapackages. Limits edges to a single numerical value without uncertainty, but gives better performance for large IO data.
+* `multifunctional`: Stores `multifunctional` processes as a custom node type, and automatically allocates following the given database or process preferences when creating datapackages.
+
+### Searching
+
+**Q:** How do I search a `Database`?
+
+```python
+bd.Database('<database_name>').search('<my_query_string>')
+```
+
+See {py:obj}`bw2data.backends.base.SQLiteBackend.search` for documentation and function options.
+
+### Datapackages
+
+**Q:** How do I get the `bw_processing` datapackage for this `Database`?
+
+```python
+bd.Database('<database_name>').datapackage()
+```

source/content/cheatsheet/ia.md

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+## Impact Assessment
+
+### Impact Categories (`Method`)
+
+**Q:** How do I list the installed impact categories?
+
+```python
+sorted(bd.methods)
+```
+
+**Q:** How do I test if a given impact category is installed?
+
+```python
+('<impact>', '<category>') in bd.methods
+```
+
+**Q:** How can I get a random impact category?
+
+```python
+bd.methods.random()
+```
+
+**Q:** How do I search for an impact category using list comprehensions?
+
+```python
+[
+    method for method in bd.methods
+    if 'ilcd 2.0' in method[0].lower()
+    and 'LT' not in method[2]
+]
+```
+
+**Q:** How do I see the data in a given impact category?
+
+```python
+my_method_object = bd.Method(('<impact>', '<category>'))
+list(my_method_object)
+```
+
+**Q:** How is the data in impact categories structured?
+
+Iterating over a `Method` object yields tuples.
+
+* The first element in the tuple will be the biosphere `Node`
+* The second element will be the characterization factor, either as a number, or as a dictionary which includes uncertainty information
+* There could be a third element, which gives the *location* for the characterization factor. This third element is not required.
+
+**Q:** How do I interpret the uncertainty dictionary?
+
+See the [`stats_arrays` documentation](https://stats-arrays.readthedocs.io/en/latest/#mapping-parameter-array-columns-to-uncertainty-distributions).
+
+**Q:** How do I create a new impact category?
+
+Start by defining characterization data following the tuple format defined in `How is the data in impact categories structured?`:
+
+```python
+import stats_arrays as sa
+my_cf_data = [
+    (biosphere_node_1, 42),
+    (biosphere_node_1, 23, 'BR'),
+    (biosphere_node_2, {
+        'uncertainty_type': sa.TriangularUncertainty.id,
+        'amount': 7,
+        'loc': 7,
+        'maximum': 21
+    })
+]
+```
+
+Then write the characterization factor to the `Method`:
+
+```python
+bd.Method(('<impact>', '<category>')).write(my_cf_data)
+```
+
+**Q:** How do I see the impact category metadata?
+
+```python
+bd.Method(('<impact>', '<category>')).metadata
+```
+
+**Q:** How do I change the impact category metadata?
+
+```python
+bd.Method(('<impact>', '<category>')).metadata['<some_key>'] = '<some_value>'
+```

source/content/cheatsheet/importing.md

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+## Importing data
+
+The philosophy and workflow for importing data is explained in the "Overview".
+
+```{admonition} Before starting an import
+:class: important
+Make sure you have the basic data, such as background data and biosphere flows available. It will probably be needed to create links with your imported data.
+```
+
+### Creating Importers
+
+**Q:** How do I start an import from the Brightway excel template?
+
+```python
+importer = bi.ExcelImporter('<file_path>')
+```
+
+See {py:obj}`bw2io.importers.excel.ExcelImporter` for additional information.
+
+**Q:** How do I start an import from SimaPro CSV?
+
+```python
+from pathlib import Path
+importer = bi.SimaProBlockCSVImporter(Path('<file_path>'))
+```
+
+See {py:obj}`bw2io.importers.simapro_block_csv.SimaProBlockCSVImporter` for additional information.
+
+**Q:** How do I start an import from Ecospold 1?
+
+```python
+importer = bi.SingleOutputEcospold1Importer('<directory_path>', '<database_name>')
+```
+
+See {py:obj}`bw2io.importers.ecospold1.SingleOutputEcospold1Importer` for additional information.
+
+**Q:** How do I start an import from Ecospold 1?
+
+```python
+importer = bi.SingleOutputEcospold2Importer('<directory_path>', '<database_name>')
+```
+
+See {py:obj}`bw2io.importers.ecospold2.SingleOutputEcospold2Importer` for additional information.
+
+### Ecoinvent
+
+**Q:** How can I import an ecoinvent release using the online portal?
+
+```python
+bi.import_ecoinvent_release(
+    version='<version_number>',
+    system_model='<system_model>',
+    ecoinvent_user='<ecoinvent_user_name>',
+    ecoinvent_password='<ecoinvent_password>'
+)
+```
+
+The `import_ecoinvent_release` function will create a namespaced set of impact categories and a separate namespaced biosphere `Database`.
+
+```{warning}
+The setup function `bw2setup()` is deprecated and should no longer be used.
+```
+
+See {py:obj}`bw2io.ecoinvent.import_ecoinvent_release` for customization options, and the [`ecoinvent_interface` documentation](https://github.com/brightway-lca/ecoinvent_interface/?tab=readme-ov-file#authentication-via-settings-object) for instructions on how to download additional ecoinvent data and save your credentials.
+
+**Q:** How can I import a local copy of an ecoinvent release?
+
+Start with a basic project which has the correct set of elementary flows for your given release - see [Creating initial project data](initial-project-data). You can then use the standard ecospold2 importer:
+
+```python
+importer = bi.SingleOutputEcospold2Importer(
+    dirpath='<ecoinvent_database_zip_file>',
+    dbname='<database_name>'
+)
+importer.apply_strategies()
+importer.write_database()
+```
+
+We strongly recommend that you follow the `ecoinvent-<version>-<system model>` database naming pattern.
+
+### Applying Transformations
+
+**Q:** How do I apply the default transformation strategies?
+
+```python
+importer.apply_strategies()
+```
+
+**Q:** How do I apply a custom transformation strategy?
+
+```python
+importer.apply_strategy(<my_function>)
+```
+
+**Q:** How do I write a custom transformation strategy?
+
+Transformation functions must take the entire import data as the single input argument, and return the modified entire import data. They should follow this general pattern:
+
+```python
+from typing import List
+
+def my_custom_strategy(data: List[dict]) -> List[dict]:
+    """Add very import information to each dataset"""
+    for dataset in data:
+        dataset["this is a dataset"] = True
+    return data
+```
+
+If you need to provide additional information to a transformation strategy, you can [curry](https://en.wikipedia.org/wiki/Currying) the transformation function:
+
+```python
+from typing import List
+from functools import partial
+
+def my_custom_strategy(data: List[dict], favorite_color: str) -> List[dict]:
+    """Add very import color information"""
+    for dataset in data:
+        dataset["my favorite color"] = favorite_color
+    return data
+
+importer.apply_strategy(partial(my_custom_strategy, favorite_color="blue"))
+```
+
+**Q:** How do I change the default strategies?
+
+`importer.strategies` is a list, and the normal Python list methods can be used to modify the list before `.apply_strategies()` is called. You can also replace `importer.strategies` completely:
+
+```python
+importer.strategies = [<some functions>]
+```
+
+**Q:** How can I apply static transformations from [randonneur_data](https://github.com/brightway-lca/randonneur_data)?
+
+```python
+importer.randonneur('<transformation_label')
+```
+
+See {py:obj}`bw2io.importers.base_lci.LCIImporter.randonneur` for customization of this function's behavior.
+
+### Creating Links
+
+**Q:** How do I realize internal links among the nodes in my imported data?
+
+```python
+importer.match_database()
+```
+
+See {py:obj}`bw2io.importers.base_lci.LCIImporter.match_database` for customization of this function's behavior.
+
+**Q:** How do I realize external links from my imported data to other `Databases`?
+
+```python
+importer.match_database('<database_label>')
+```
+
+See {py:obj}`bw2io.importers.base_lci.LCIImporter.match_database` for customization of this function's behavior.
+
+### Linking Status
+
+**Q:** How can I quickly check if all edges are linked?
+
+```python
+importer.all_linked
+```
+
+**Q:** How can I see how many edges have been linked so far?
+
+```python
+importer.statistics()
+```
+
+**Q:** How can I export an Excel file of the unlinked edges?
+
+```python
+filepath = importer.write_excel(only_unlinked=True)
+```
+
+**Q:** How can I export a Randonneur template for matching unlinked edges?
+
+```python
+filepath = importer.create_randonneur_excel_template_for_unlinked()
+```
+
+See {py:obj}`bw2io.importers.base_lci.LCIImporter.create_randonneur_excel_template_for_unlinked` for customization of this function's behavior.
+
+### Handling Unlinked Edges
+
+**Q:** How can I iterate over all unique unlinked edges?
+
+```python
+for edge in importer.unlinked:
+    do_something(edge)
+```
+
+**Q:** How can I delete unlinked edges?
+
+```python
+importer.drop_unlinked(i_am_reckless=True)
+```
+
+**Q:** How can I add biosphere nodes from my imported data?
+
+You can leave such biosphere nodes in the `Database` you are going to create, but you can separate them out into a new `Database`:
+
+```python
+importer.create_new_biosphere('<new_database_name>')
+```
+
+You can also add them to an existing database:
+
+```python
+importer.add_unlinked_flows_to_biosphere_database('<existing_database_name>')
+```
+
+**Q:** How can I create placeholder process or product nodes referenced in my imported data but without any producers?
+
+```python
+importer.add_unlinked_activities()
+```