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By default, an Association node builds one model using the Apriori algorithm. The Apriori algorithm assumes the following:
The data is transactional.
The data has many missing values. The apriori algorithm interprets all missing values as sparse data, and it has its own mechanisms for handling sparse data.
All models in the node have the same case ID, item ID, and item value. The case ID can be two columns. For example, the data sources SH.SALES, CUST_ID and TIME_ID combined can be the case ID.
No automatic data preparation is done for an Association node. If you select a value for Item Value that is different from the default <Existence>, you might have to prepare the data.