kedro.extras.datasets.pandas.SQLTableDataSet¶
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class
kedro.extras.datasets.pandas.
SQLTableDataSet
(table_name, credentials, load_args=None, save_args=None, layer=None)[source]¶ Bases:
kedro.io.core.AbstractDataSet
SQLTableDataSet
loads data from a SQL table and saves a pandas dataframe to a table. It usespandas.DataFrame
internally, so it supports all allowed pandas options onread_sql_table
andto_sql
methods. Since Pandas uses SQLAlchemy behind the scenes, when instantiatingSQLTableDataSet
one needs to pass a compatible connection string either incredentials
(see the example code snippet below) or inload_args
andsave_args
. Connection string formats supported by SQLAlchemy can be found here: https://docs.sqlalchemy.org/en/13/core/engines.html#database-urlsSQLTableDataSet
modifies the save parameters and stores the data with no index. This is designed to make load and save methods symmetric.Example:
from kedro.extras.datasets.pandas import SQLTableDataSet import pandas as pd data = pd.DataFrame({"col1": [1, 2], "col2": [4, 5], "col3": [5, 6]}) table_name = "table_a" credentials = { "con": "postgresql://scott:tiger@localhost/test" } data_set = SQLTableDataSet(table_name=table_name, credentials=credentials) data_set.save(data) reloaded = data_set.load() assert data.equals(reloaded)
Attributes
SQLTableDataSet.DEFAULT_LOAD_ARGS
SQLTableDataSet.DEFAULT_SAVE_ARGS
Methods
SQLTableDataSet.__init__
(table_name, credentials)Creates a new SQLTableDataSet
.SQLTableDataSet.exists
()Checks whether a data set’s output already exists by calling the provided _exists() method. SQLTableDataSet.from_config
(name, config[, …])Create a data set instance using the configuration provided. SQLTableDataSet.get_last_load_version
()Versioned datasets should override this property to return last loaded version SQLTableDataSet.get_last_save_version
()Versioned datasets should override this property to return last saved version. SQLTableDataSet.load
()Loads data by delegation to the provided load method. SQLTableDataSet.release
()Release any cached data. SQLTableDataSet.save
(data)Saves data by delegation to the provided save method. -
DEFAULT_LOAD_ARGS
= {}¶
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DEFAULT_SAVE_ARGS
= {'index': False}¶
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__init__
(table_name, credentials, load_args=None, save_args=None, layer=None)[source]¶ Creates a new
SQLTableDataSet
.Parameters: - table_name (
str
) – The table name to load or save data to. It overwrites name insave_args
andtable_name
parameters inload_args
. - credentials (
Dict
[str
,Any
]) – A dictionary with aSQLAlchemy
connection string. Users are supposed to provide the connection string ‘con’ through credentials. It overwrites con parameter inload_args
andsave_args
in case it is provided. To find all supported connection string formats, see here: https://docs.sqlalchemy.org/en/13/core/engines.html#database-urls - load_args (
Optional
[Dict
[str
,Any
]]) – Provided to underlying pandasread_sql_table
function along with the connection string. To find all supported arguments, see here: https://pandas.pydata.org/pandas-docs/stable/generated/pandas.read_sql_table.html To find all supported connection string formats, see here: https://docs.sqlalchemy.org/en/13/core/engines.html#database-urls - save_args (
Optional
[Dict
[str
,Any
]]) – Provided to underlying pandasto_sql
function along with the connection string. To find all supported arguments, see here: https://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.to_sql.html To find all supported connection string formats, see here: https://docs.sqlalchemy.org/en/13/core/engines.html#database-urls It hasindex=False
in the default parameters. - layer (
Optional
[str
]) – The data layer according to the data engineering convention: https://kedro.readthedocs.io/en/stable/06_resources/01_faq.html#what-is-data-engineering-convention
Raises: DataSetError
– When eithertable_name
orcon
is empty.Return type: None
- table_name (
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exists
()¶ Checks whether a data set’s output already exists by calling the provided _exists() method.
Return type: bool
Returns: Flag indicating whether the output already exists. Raises: DataSetError
– when underlying exists method raises error.
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classmethod
from_config
(name, config, load_version=None, save_version=None)¶ Create a data set instance using the configuration provided.
Parameters: - name (
str
) – Data set name. - config (
Dict
[str
,Any
]) – Data set config dictionary. - load_version (
Optional
[str
]) – Version string to be used forload
operation if the data set is versioned. Has no effect on the data set if versioning was not enabled. - save_version (
Optional
[str
]) – Version string to be used forsave
operation if the data set is versioned. Has no effect on the data set if versioning was not enabled.
Return type: AbstractDataSet
Returns: An instance of an
AbstractDataSet
subclass.Raises: DataSetError
– When the function fails to create the data set from its config.- name (
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get_last_load_version
()¶ Versioned datasets should override this property to return last loaded version
Return type: Optional
[str
]
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get_last_save_version
()¶ Versioned datasets should override this property to return last saved version.
Return type: Optional
[str
]
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load
()¶ Loads data by delegation to the provided load method.
Return type: Any
Returns: Data returned by the provided load method. Raises: DataSetError
– When underlying load method raises error.
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release
()¶ Release any cached data.
Raises: DataSetError
– when underlying exists method raises error.Return type: None
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save
(data)¶ Saves data by delegation to the provided save method.
Parameters: data ( Any
) – the value to be saved by provided save method.Raises: DataSetError
– when underlying save method raises error.Return type: None
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