Datastore Fetcher
Fetch dataset resource data from the DataStore.
This fetcher is used to fetch data from the DataStore using the resource ID.
__init__(resource_id, resource_view_id=None, settings=None, limit=1000, cache_strategy=None)
Initialize the DatastoreDataFetcher.
| PARAMETER | DESCRIPTION |
|---|---|
resource_id
|
The ID of the resource to fetch data for.
TYPE:
|
settings
|
The settings for the chart.
TYPE:
|
limit
|
The maximum number of rows to fetch.
TYPE:
|
cache_strategy
|
The cache strategy to use. If not provided, the configured cache strategy will be used.
TYPE:
|
build_sort_clauses()
Build sort clauses for SQL query based on settings.
cache_column_metadata(columns)
Cache the complete column list for the resource.
| PARAMETER | DESCRIPTION |
|---|---|
columns
|
List of column names to cache
TYPE:
|
fetch_data()
Fetch data from the DataStore.
| RETURNS | DESCRIPTION |
|---|---|
DataFrame
|
pd.DataFrame: Data from the DataStore |
get_all_column_names()
Get all column names from the table, excluding system columns.
This method doesn't format the columns, just returns their names. It's used both internally and can be used by form builders.
| RETURNS | DESCRIPTION |
|---|---|
list[str]
|
List of all column names in the resource |
get_needed_columns()
Extract a set of all column names required for chart generation.
This includes: - Fields explicitly defined in the chart settings (e.g., 'x', 'y', 'color', etc) - Filter columns used in the 'filter' expression (e.g., 'column:value|...')
invalidate_cache()
Invalidate the cache for the data fetcher.
make_cache_key()
Generate a cache key for the DataStore data fetcher.
Uses both resource_id and resource_view_id (if available) as part of the cache key.
| RETURNS | DESCRIPTION |
|---|---|
str
|
The cache key
TYPE:
|
make_metadata_cache_key()
Generate a cache key for the resource metadata (column list).
| RETURNS | DESCRIPTION |
|---|---|
str
|
The metadata cache key |
parse_filters()
Parse filter string from settings into SQLAlchemy query.
| RETURNS | DESCRIPTION |
|---|---|
list[ClauseElement]
|
List of SQLAlchemy filter query (e.g., column == value). |
update_view_id(resource_view_id)
Update the resource view ID after view creation.
If data was cached with just the resource_id, this method will move the cached data to a key that includes the view_id.
| PARAMETER | DESCRIPTION |
|---|---|
resource_view_id
|
The new resource view ID
TYPE:
|