Use datasets from external application

To access a dataset on a Terracotta DB server, which has been generated by an external application, you must configure a Terracotta DB connection in MashZone NextGen in advance. Terracotta DB connections can be defined in the MashZone NextGen Admin console. For details, see Manage Terracotta DB connections.

Procedure

  1. Create a new data feed or open an existing data feed.
  2. Insert a Terracotta DB data source. For details, see Select data sources.
  3. Select Dataset in the Source drop-down menu.
  4. Select a Terracotta DB connection in the Terracotta DB alias drop-down menu. The alias specifies the Terracotta DB server you want to connect with. The menu contains all available Terracotta DB connections you have Usage privilege for.
  5. Select a dataset alias in the Dataset name drop-down menu. The menu contains all available Terracotta DB datasets for the selected Terracotta DB alias. For details, see Manage Terracotta DB connections. Datasets on the Terracotta DB server generated by MashZone NextGen for Materialized Feeds are excluded from the list.
  6. Click Configure columns to configure the columns of the dataset.

    When selecting a dataset, schema guessing is used to derive its columns. Using 1000 records, the guessing mechanism derives the set of all unique cell definitions of those records and defines corresponding columns.

    1. Unselect a column to exclude it from processing.
    2. Select or enter a (positive) Sample size and click Derive columns to re-run the schema guessing with a larger sample size. The current configuration is omitted. The larger the sample size is, the longer the schema guessing takes.

      Click Add column to manually add a new column.

    3. Enter a unique column name and select a data type for the new column.

      The combination of name and type must fit to the cell definition in the store. If not, the corresponding values will always be null. For example, if the cell definition is age with type INT and you specify age with type DOUBLE, the column definition does not fit to the cell definition and the values are null.

  7. Configure the RAQL query, refresh rate, and input parameters. For details, see Terracotta DB data source.
  8. Your settings are applied.