Create a Dataset with Python Code

Options
gblack686
gblack686 Partner, Registered Posts: 62 Partner

Goal is to query the Redshift DB for table names and return a dropdown for users in a plugin.

Problem: Where to store the interim table from SQL?

query = "SELECT * FROM PG_TABLES"
db_tables = dataiku.Dataset('db_tables')
SQLExecutor2.exec_recipe_fragment(db_tables, query)

TypeError
: 'NoneType' object is not subscriptable

It seems the Dataset object cannot be created this way? Is there a workaround? Aside from using an empty dataset as an input to the plugin?

Answers

  • Marlan
    Marlan Neuron 2020, Neuron, Registered, Dataiku Frontrunner Awards 2021 Finalist, Neuron 2021, Neuron 2022, Dataiku Frontrunner Awards 2021 Participant, Neuron 2023 Posts: 316 Neuron
    Options

    Here's an example of how to create a dataset programatically. In this case a text dataset (I can share code for SQL if interested, it's similar but of course not exactly the same). I extracted this from a larger process so may not have gotten all the needed pieces but nonetheless should be a place to start. In particular, you'll need to populate the variable to pass the set_schema method. You can do a get_schema on an existing dataset to see the format.

    Marlan

    import dataikuimport dataikuapiclient = dataiku.api_client()project = client.get_project(dataiku.default_project_key())project_variables = dataiku.get_custom_variables()csv_dataset_name = 'NEW_DATASET_NAME'# Create dataset if it doesn't already existtry:# If dataset exists, clear itcsv_dataset = project.get_dataset(csv_dataset_name) # doesn't generate error if dataset doesn't existcsv_dataset.clear()except:# Create dataset (assuming exception was that dataset does not exist)params = {'connection': 'filesystem_folders', 'path': project_variables['projectKey'] + '/' + csv_dataset_name}format_params = {'separator': '\t', 'style': 'unix', 'compress': ''}csv_dataset = project.create_dataset(csv_dataset_name, type='Filesystem', params=params,formatType='csv', formatParams=format_params)# Set dataset to managedds_def = csv_dataset.get_definition()ds_def['managed'] = Truecsv_dataset.set_definition(ds_def)# Set schemacsv_dataset.set_schema({'columns': csv_dku_schema_columns})# If you want to delete it later...csv_dataset.clear() # removes folder and filecsv_dataset.delete()
  • berndito
    berndito Registered Posts: 6 ✭✭✭✭
    Options

    I think this is a useful example of how to create datasets dynamically by Python code.

    However, I see now method how to write data from a Pandas dataset to the created Dataiku dataset?

    I checked the dataikuapi reference, but could not find any applicable method.

    Would be great if the example above could be extended to explain how to do realize it.

    The example in the documentation shows following code:

    project = client.get_project('TEST_PROJECT')folder_path = 'path/to/folder/'for file in listdir(folder_pathif not file.endswith('.csv'continuedataset = project.create_dataset(file[:-4]  # dot is not allowed in dataset names,'Filesystem', params={'connection': 'filesystem_root','path': folder_path + file}, formatType='csv', formatParams={'separator': ',','style': 'excel'  # excel-style quoting,'parseHeaderRow': True})df = pandas.read_csv(folder_path + file)dataset.set_schema({'columns': [{'name': column, 'type':'string'} for column in df.columns]}

    But unfortunately, the example doesn't actually show how to write the Pandas df .

    Thanks in advance!

  • Marlan
    Marlan Neuron 2020, Neuron, Registered, Dataiku Frontrunner Awards 2021 Finalist, Neuron 2021, Neuron 2022, Dataiku Frontrunner Awards 2021 Participant, Neuron 2023 Posts: 316 Neuron
    Options

    Hi @berndito
    ,

    Check https://doc.dataiku.com/dss/latest/python-api/datasets.html for documentation on writing dataframes. See the method write_dataframe in the Dataset class.

    Marlan

  • leneborma
    leneborma Registered Posts: 1 ✭✭✭
    Options

    The error is self-explanatory. You are trying to index None. You can not, because 'NoneType' object is not subscriptable. This means that you tried to do:

    None[something]

    In general, the error means that you attempted to index an object that doesn't have that functionality. You might have noticed that the method sort() that only modify the list have no return value printed – they return the default None. This is a design principle for all mutable data structures in Python.

  • epsi95
    epsi95 Dataiku DSS Core Concepts, Registered Posts: 15 ✭✭✭✭
    Options

    Here is a list of operation in python code

    import dataikuimport dataikuapidef load_database_whole(database_name):dataset = dataiku.Dataset(database_name)df = dataset.get_dataframe()return dfdef load_database_sample(database_name):dataset = dataiku.Dataset(database_name)df = dataset.get_dataframe(limit=5)return dfdef save_database(df, database_name):client = dataiku.api_client()project = client.get_project(dataiku.default_project_key())project_variables = dataiku.get_custom_variables()# Create datasetparams = {'connection': 'filesystem_folders', 'path': project_variables['projectKey'] + '/' + database_name}format_params = {'separator': '\t', 'style': 'unix', 'compress': ''}csv_dataset = project.create_dataset(database_name, type='Filesystem', params=params, formatType='csv', formatParams=format_params)# Set dataset to managedds_def = csv_dataset.get_definition()ds_def['managed'] = Truecsv_dataset.set_definition(ds_def)dataset = dataiku.Dataset(database_name)dataset.write_with_schema(df)def get_list_of_available_databases():return dataiku.Dataset.list()
  • isha
    isha Registered Posts: 1 ✭✭✭
    Options

    Can you please share the code for SQL(I am using snowflake connection). I get error when i try to write to the dataset using dataiku.Dataset(dataset_name,ignore_flow=True).write_with_schema(df)

    I have created the dataset in the same python recipe in prev lines using

    builder = project.new_managed_dataset_creation_helper(dataset_name)

    builder.with_store_into("snowflakeconnectionname")

    builder.create()

    the line dataiku.Dataset(dataset_name,ignore_flow=True).write_with_schema(df) throws error None: dataset does not exist

  • Marlan
    Marlan Neuron 2020, Neuron, Registered, Dataiku Frontrunner Awards 2021 Finalist, Neuron 2021, Neuron 2022, Dataiku Frontrunner Awards 2021 Participant, Neuron 2023 Posts: 316 Neuron
    Options

    Hi @isha
    ,

    The approach I used was lower level as that was needed for the version of DSS I was using when I did this. Your higher level approach follows the current documentation so it certainly seems like it should work.

    Can you apply other methods to the dataset returned from dataiku.Dataset(dataset_name, ignore_flow=True)? I would assume not as the error is dataset does not exist.

    I did share my approach below but as noted it uses a different and lower level approach that wouldn't help you figure out why what you are doing doesn't work.

    dataset_name = 'PROGRAM_CREATED_DATASET'try:dataset_handle = project.get_dataset(dataset_name) # doesn't generate error if dataset doesn't existdataset_handle.clear() # this however does generate an error if dataset doesn't existexcept:# Create dataset (assuming exception was that dataset does not exist)params = {'connection': 'NETEZZA_CONNECTION_NAME', 'mode': 'table', 'table': 'SQL_TABLE_NAME}dataset_handle = project.create_dataset(dataset_name, type='Netezza', params=params)# Set dataset to managed assuming with be the output of a recipeds_def = dataset_handle.get_definition()ds_def['managed'] = Truedataset_handle.set_definition(ds_def)# Set schema (this may not be needed as recipe execution should populate the schema)dataset_handle.set_schema({'columns': schema_columns}) # check get_schema() of existing dataset to see structure to use

    Marlan

  • vamsi
    vamsi Registered Posts: 1 ✭✭✭
    Options

    please tell me how to create a dataset using python

Setup Info
    Tags
      Help me…