Joins multiple instances of different source types into one instance of the target type, based on one or more matching properties.

Category: General



Function ID: eu.esdihumboldt.hale.align.join

Join order

The first step for creating a join transformation is to select the order of the source types. For each instance of the topmost type a target instance will be created. The following types will be joined in order to fill the result with additional information. This can also result in several instances of the second type for one particular instance of the first type. The third type then can have several instances matching one of those instances of the second type (or the first type again depending on the conditions) and so on.


Each type after the first needs at least one join condition on the previous types. It can have conditions on only one of the previous types but it may also have conditions on several of them. Conditions are simple equalities. A property of the joined type is compared to the selected property of a base type. If all these conditions are equal the instance is used. A particular instance may match more than one instance of the previous types and will then be used each time.

To create a condition, select a property on the left and on the right side, then click on the button in the middle.