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In Prequel Import, a Dataset is a materialized cache of data representing a connected Source table or custom SQL query. Datasets are maintained in the Datalake.

Types of Datasets

For efficiency, Prequel Import requires each Dataset to be assigned a type: Dimension or Fact.
  • Dimension: A table containing rows that may be updated over time (e.g., users, products, accounts). Prequel Import tracks changes and syncs updates to existing records.
  • Fact: An append-only table containing immutable events or transactions (e.g., events, page views, logs). New records are added but existing records are never modified. Prequel Import assumes records that have been successfully delivered to the Destination do not need to be monitored for changes.
To understand how Change Detection works for either table type, see the Change Detection guide.

Dataset configuration

FieldTypeRequiredDescription
source_iduuidYesThe ID of the Source this Dataset is connected to.
source_object_namespacestringYesThe namespace (e.g., schema or database) containing the source table.
source_object_namestringYesThe name of the table or object in the Source.
typestringYesThe type of Dataset. One of dimension, fact.
frequency_minutesintegerYesHow often (in minutes) Prequel checks this Dataset for changes.
dimensionobjectRequired if type is dimensionConfiguration for dimension datasets. See below.
factobjectRequired if type is factConfiguration for fact datasets. See below.

Dimension configuration

FieldTypeRequiredDescription
primary_key_columnstringYesThe column used to uniquely identify records.
last_modified_columnstringNoThe column used to track when records were last modified. Used for incremental sync. Set to null for full sync.
is_deleted_columnstringNoA column that flags soft-deleted records.

Fact configuration

FieldTypeRequiredDescription
primary_key_columnstringYesThe column used to uniquely identify records.
created_at_columnstringYesThe column recording when each record was created. Required for efficient append-only change detection.