IntakeSQLSource  type: intake_sql#

class lumen.sources.intake_sql.IntakeSQLSource(*, filter_in_sql, catalog, dask, uri, load_schema, cache_dir, cache_per_query, cache_with_dask, root, shared, name)#

IntakeSQLSource extends the IntakeSource with support for SQL data.

In addition to the standard intake support for reading catalogs the IntakeSQLSource computes the schema by querying the database instead of loading all the data into memory and allows for SQLTransform to be applied when querying the SQL database.

Parameters#

catalog

type: dict
default: None
An inlined Catalog specification.

dask

type: bool
default: False
Whether to return a dask DataFrame.

filter_in_sql

type: bool
default: True

load_schema

type: bool
default: True
Whether to load the schema

uri

type: str
default: ''
URI of the catalog file.

Methods#

IntakeSQLSource.clear_cache(*events: Event)#

Clears any cached data.

IntakeSQLSource.create_sql_expr_source(tables: dict[str, str], **kwargs)#

Creates a new SQL Source given a set of table names and corresponding SQL expressions.

IntakeSQLSource.execute(sql_query: str) → DataFrame#

Executes a SQL query and returns the result as a DataFrame.

Parameters:

sql_query (str) – The SQL Query to execute

Returns:

The result as a pandas DataFrame

Return type:

pd.DataFrame

IntakeSQLSource.get(table, **query)#

Applies SQL Transforms, creating new temp catalog on the fly and querying the database.

IntakeSQLSource.get_schema(table: str | None = None, limit: int | None = None) → dict[str, dict[str, Any]] | dict[str, Any]#

Returns JSON schema describing the tables returned by the Source.

Parameters:

  • table (str | None) – The name of the table to return the schema for. If None returns schema for all available tables.

  • limit (int | None) – Limits the number of rows considered for the schema calculation

Returns:

JSON schema(s) for one or all the tables.

Return type:

dict

IntakeSQLSource.get_sql_expr(table)#

Returns the SQL expression corresponding to a particular table.

IntakeSQLSource.get_tables()#

Returns the list of tables available on this source.

Returns:

The list of available tables on this source.

Return type:

list

IntakeSQLSource.to_spec(context: dict[str, Any] | None = None) → dict[str, Any]#

Exports the full specification to reconstruct this component.

Return type:

Resolved and instantiated Component object