## Using a Subset During Creation of Many to Many Rules

The Subset rule for Many to Many match types enables you to match one or more transactions in a data source with all subset of transactions in another data source. The specified tolerance limit is applied to both the data sources.

Example of Many to Many with Subset Rule

Consider a match type that contains two data sources, with POS as the source system and Bank as the subsystem. The table below shows a limited set of transactions that are required for the purpose of this example.

Table 9-5 Source System Transactions

Transaction Id Store Id Transaction Date Amount
10001 7959 15-JUL-2021 983
20001 7959 14-JUL-2021 637
30001 7959 11-JUL-2021 288
40001 7959 10-JUL-2021 500
50001 7959 09-JUL-2021 818

Table 9-6 SubSystem Transactions

Transaction Id Store Id Transaction Date Amount
19999 7959 14-JUL-2021 -475
29999 7959 16-JUL-2021 2095
39999 7959 15-JUL-2021 -725

Notice that, although their dates are not an exact match, the transactions with Transaction Id 10001 and 20001 in the source system add up to an amount of 1620. The transactions with Transaction Id 19999 and 29999 in the subsystem add up to the same amount, 1620.

Consider the rule condition to match exactly with Amount and Store Id, anchor the Date, and then apply the specified tolerance limit on the Date. Assume that the specified tolerance is + or - 1 day. In our example, consider the first source system transaction dated 15-JUL-2021. If you use the Many to Many rule (without subset), the source system transactions that match the rule condition are Transaction Ids 10001 and 20001, whose amount adds up to 1620. In the subsystem, all transactions match the rule condition and their amounts add up to 895. This does not result in an exact match. However, when you use the Many to Many with Subset rule, all possible subsets of the subsystem transactions are created based on the specified match rules. This results in the subset with Transaction Ids 19999 and 29999 in the subsystem matching with Transaction Ids 10001 and 20001 in the source system.

Specifying the Many to Many with Subset Rule

To create a Many to Many with Subset rule, you must:

• Select a data source in With Subset
• Include at least one attribute in Groups

You can apply the subset rule to the source system or subsystem. In the New Rule dialog, use With Subset to select the data source on which the subset rule must be applied. The other data source is used as the anchor for applying the specified tolerance limit. For example, your match type has two data sources, Bank and POS. If you select Bank under With Subset, the subset rule is applied to Bank and a subset of transactions in Bank is matched with a one or more transactions in POS. The POS is used as an anchor and the specified tolerance limit is applied on both POS and Bank.

In the Groups section of the Rule Conditions tab, ensure that you define at least one group for the anchored data or at least one exact match rule condition. To define a group, in the Groups section, select one or more attributes from the anchored data source. Notice that grouping is disabled for the data source that you selected in With Subset.

Note: If you donâ€™t select a data source in With Subset, the behavior is the same a Many to Many rule type (without subset).