59. Joiners
Joiners serve to join data from more data sources according to key values.
We can distinguish Joiners according to how they process data. Most Joiners work using key values.
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Some Joiners read data from two or more input ports and join them according to the equality of key values.
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ExtHashJoin joins two or more data inputs according to the equality of key values.
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ExtMergeJoin joins two or more sorted data inputs according to the equality of key values.
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Other Joiners read data from one input port and another data source and join them according to the equality of key values.
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DBJoin joins one input data source and a database according to the equality of key values.
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LookupJoin joins one input data source and a lookup table according to the equality of key values.
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One Joiner joins data according to the user-defined relation of key values.
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RelationalJoin joins two or more sorted data inputs according to the user-defined relation of key values (
!=,>,>=,<,<=).
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Combine joins data flows by tuples.
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CrossJoin creates a Cartesian product of records from connected input ports.