CrossJoin

Short Description

CrossJoin creates a Cartesian product of records from connected input ports.

COMPONENT	SAME INPUT METADATA	SORTED INPUTS	SLAVE INPUTS	OUTPUTS	OUTPUT FOR DRIVER WITHOUT SLAVE	OUTPUT FOR SLAVES WITHOUT DRIVER	JOINING BASED ON EQUALITY	AUTO-PROPAGATED METADATA
CrossJoin	x	x	0-n	1	x	x	x	✓

Ports

PORT TYPE	NUMBER	REQUIRED	DESCRIPTION	METADATA
Input	0	✓	Master input port	Any1
	1-n	x	Slave input port(s)	Any2
Output	0	✓	For output data records	Any3

Metadata

CrossJoin automatically generates metadata on the output port from metadata on its input ports. The generated metadata can be seen as a dynamic template.

CrossJoin Attributes

ATTRIBUTE	REQ	DESCRIPTION	POSSIBLE VALUES
Transform	[1]	A transformation in CTL or Java defined in the graph.
Transform URL	[1]	An external file defining the transformation in CTL or Java.
Transform class	[1]	An external transformation class.
Transform source charset		Encoding of an external file defining the transformation.	E.g. UTF-8

[1] At most one of these attributes can be set.

Details

CrossJoin creates a Cartesian product of input records.

It works in the following way: the component takes the first record from the first port, the first record from the second port (…) and the first record from the last port and generates the output record. Subsequently, it takes the first record from the first port, the first record from the second port (…) and the second record from the last port. It continues with the third record from the last input port and so on.

Processing Large Number of Records
If you process a very large number of records, temporary files with the swapped records may be created on your hard drive. This prevents excessive memory usage.

Examples

Simple CrossJoin Example
Given a list of customers and a list of products of "All on the Store Ltd."
Customers:

Brown
Smith
Jones

Goods:

Pineapple
Turnip
Spaceship

Create a list containing all possibilities.

Solution
You only need to connect sources of data with CrossJoin component. No setup of attributes of the component is necessary.
The result is:

Brown|Pineapple
Brown|Turnip
Brown|Spaceship
Smith|Pineapple
Smith|Turnip
Smith|Spaceship
Jones|Pineapple
Jones|Turnip
Jones|Spaceship

Best Practices

The edge giving the most records should be connected to the first input port.
If the transformation is specified in an external file (with Transform URL), we recommend users to explicitly specify Transform source charset.