About Delta Changes for Attributes
The Reltio Platform calculates the attribute deltas between the initial state of the object, that is, before the object was updated, and the state of the object after it is updated.
When any entity or relationship object is updated in the Reltio Platform, it stores the attribute delta changes inside an activity log item in the deltaCollection field, which contains the following properties:
ovChanged: This flag indicates whether any of the operational values are changed or not.delta: This field contains a collection of attribute deltas or changes, which provide information about the sub-field value before and after the entity or relationship object is changed such as the Operational Values (OV), OV flag of the values, and information about the sources for which the values are changed. Following are the possible delta types:ATTRIBUTE_ADDEDATTRIBUTE_REMOVEDATTRIBUTE_CHANGED
The ovChanged flag also can be passed to the streamed events in the
                case where analyzeOvChanges is enabled in the tenant streaming
                configuration.
ovChanged flag is always true for
                    ENTITY_CHANGED events sent for these related entities due to a
                reference attribute change. This is a type of optimization to avoid potential huge
                negative performance impact in delta calculation in the event some referenced entity
                with numerous related entities was changed.View the deltaCollection Field Types
| Field | Type | 
|---|---|
| ovChanged | Boolean | 
| delta | JSON array of attribute deltas | 
View the Attribute Fields for Delta Changes
| Field | Type | 
|---|---|
| type | String | 
| attributeType | String | 
| newValue | JSON object of attribute values | 
| oldValue | JSON object of attribute values | 
View the Attribute Values for Delta Changes
| Field | Type | 
|---|---|
| id | String | 
| value | String or JSON object of nested attribute values | 
| ov | Boolean | 
| sources | JSON array of strings | 
View the Nested Attribute Field Values
| Field | Type | 
|---|---|
| Attribute Name | JSON object of attribute values | 
The following JSON shows the attribute deltas:
{
   "type":"ENTITY_CHANGED",
   "uri":"entities/00009ab",
   "deltas":{
      "ovChanged":true,
      "delta":[
         {
            "type":"ATTRIBUTE_ADDED",
            "attributeType":"configuration/entityTypes/Location/attributes/Street",
            "newValue":{
               "value":"NewStreet",
               "ov":true,
               "id":"7",
               "sources":[
                  "Reltio"
               ]
            }
         },
         {
            "type":"ATTRIBUTE_CHANGED",
            "attributeType":"configuration/entityTypes/Location/attributes/City",
            "newValue":{
               "value":"ChangedCity",
               "ov":true,
               "id":"8",
               "sources":[
                  "Reltio"
               ]
            },
            "oldValue":{
               "value":"InitialCity",
               "ov":true,
               "id":"8",
               "sources":[
                  "Reltio"
               ]
            }
         },
         {
            "type":"ATTRIBUTE_REMOVED",
            "attributeType":"configuration/entityTypes/Location/attributes/Country",
            "oldValue":{
               "value":"RemovedCountry",
               "ov":false,
               "id":"9",
               "sources":[
                  "Facebook"
               ]
            }
         }
      ]
   }
}