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AO Constant Key Advanced


AO Constant Key Advanced builds and maintains a constant record key, performing all of the functions of AO Constant Key and more. It is designed to deal with the complexities of household automatic split/merge in a changing data environment, especially in financial customer-master-maintenance applications where households are fairly dynamic.

AO Constant Key Advanced works by maintaining a "Head of Household" (HOH) for all match groups. The HOH is usually the member of the household with the highest priority, or it may be assigned externally using custom business logic. AO Constant Key Advanced requires that the HOH be maintained, and also requires that each record has a persistent unique record ID that tracks individual over time

During a match update process, this macro compares the existing constant key (for example, household ID), the existing HOH, the new match groups, and the new HOH of each group. It is able to detect and adjust to the following events:

  • Split of existing groups (such as divorce or child going to college).

  • Merge of existing groups (such as marriage).

  • New members added to groups (such as a birth).

While we talk about typical individual/family events in describing this macro, it is not limited to only these situations, and works for businesses and other entities as well as individuals.

The macro accepts a single input connection (usually from a database or matching process) and produces two outputs: "D" output containing the updated data, and "H" output containing the update history for the data.

To see an example of this Advanced Object in action, open the AO Matching/Samples folder and then open the Constant Key Sample project.

AO Constant Key Advanced configuration parameters

AO Constant Key Advanced has two sets of configuration parameters in addition to the standard execution options: Input and Output.

AO Constant Key Advanced Input tab



Unique record ID

Required. New unique record identifier. Appended to the History output to the life cycle of any record as it changes over time. Default: Blank.

Existing constant key

Required. Existing unique record identifier from input data. This is used for "update" processes where the previously-matched master records will contain constant key values, but the new "update" source records will contain null values. Default: Blank.

Max existing key

Required. Highest currently assigned constant key. This is usually computed by AO Max ID or by query from the master relational database. Leave this mapping blank for the initial "build", but populate it for "update". Default: Blank.

Match ID

Required. The match ID produced by the matching process. Must be null for unique records. These values are unrelated to the existing constant keys. Default: Blank.


Required. Used to determine the master record (head-of-household) of each match group. The master record will be the record in each group with the lowest priority number. You will normally use the "group order" result from AO Match Append Info, as it will assign priority to the master/HOH. Otherwise this may be defined using AO Define Source or your custom business rule. Default: PRIORITY.

Existing HOH flag

Required. Field containing Y/N flag identifying master record of a group on the basis of match rank priority value. Typically assigned by AO Match Append Info. Existing records (from master database) must have either a Y or N assigned. New records with an empty value in this field will be initially assigned default value N. Default: Blank.

AO Constant Key Advanced Output tab

Output "D"

All input data is maintained, and the following fields are added. Output results are sent to Output "D" (Data).

Record outputs



New constant key

Required. Field for unique record identifier. This result combines the existing constant keys (if any) with the new matches to produce. Default: NEW_CONSTANT_KEY.

New HOH flag

Assign new head-of-household flag (Y/N) as appropriate. For unchanged match groups, the same record will be the head-of-household. Default: NEW_HOH_FLAG.

Move flag

This is set to "Y" for any record whose constant key was changed and "N" otherwise. Records whose Existing Constant Key is null will always receive "N" for this output. Default: MOVE_FLAG.

Group outputs



Household change flag

Set to Y to indicate the household (match group) containing this record was changed. This happens when records are added to or removed from the household, or if the head-of-household changes. Default: HH_CHANGE_FLAG.

Gain flag

This is set to "Y" when the household (match group) containing this record gains new members. Default: GAIN_FLAG.

Loss flag

This is set to "Y" when the household (match group) containing this records loses members to another household. Default: LOSS_FLAG.

Join flag

This is set to "Y" when a new household (match group) is formed from members of more than one previous household (for example, the new match group contains records with more than one Existing Constant Key value). Default: JOIN_FLAG.

HOH change flag

Set to true if the group's head of household changed or was created. Default: HOH_CHANGE_FLAG.

Time stamp

Date and time stamp of time the project was run. All output records will be assigned the same value. Default: HH_CHANGE_TIMESTAMP.

Output H (Historical Information)

Records are sent to this output if they already had constant keys (for example, in master database), and the constant key changed.



Record identifier

Unique record identifier. Appended to the History output to the life cycle of any record as it changes over time. This has the same field name as was mapped on input. Default: Blank.

Old constant key

The existing constant key that was mapped into the macro. Default: OLD_CONSTANT_KEY.

New constant key

Household ID (may be original or new value). A value of Null or -1 means the record is not included in the Historical Information output. Default: NEW_CONSTANT_KEY.

Old HOH flag

The existing head of household that was mapped into the macro. Default: OLD_HOH_FLAG.

New HOH flag

Assigned the new head-of-household flag (Y/N). Default: NEW_HOH_FLAG.

Change timestamp

Date/time stamp for records added to the Historical Information output. Aids in tracking auto-joins and auto-splits over time—allows for reversion to previous household. All output records will be assigned the same value. Default: CHANGE_TIMESTAMP.

Configure AO Constant Key Advanced

To configure AO Constant Key Advanced

  1. Select the AO Constant Key Advanced icon, and then select the Input tab on the Properties pane.

  2. Select Unique record ID and select the field containing the new unique record identifier.

  3. Select Existing constant key and select the field containing the existing unique record identifier from input data.

  4. Select Max existing key and select the field containing the highest currently assigned constant key.

  5. Select Match ID and select the field containing the match ID produced by the upstream matching process. This must be null for unique records.

  6. Select Priority and select the field containing the "group order" result from AO Match Append Info or another source.

  7. Select Existing HOH flag and select the field containing Y/N flag identifying the master record of a group. This is typically assigned using AO Match Append Info.

  8. Optionally, select the Output tab and specify alternative output field names for the fields appended to the "D" output data stream.

  9. Optionally, go to the Execution tab, and then set Web service options.

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