Every elastic table has a Partition Id column. It helps Dataverse divide records into logical partitions so the table can handle large amounts of data efficiently. If you don’t set a Partition Id when creating a row, Dataverse uses the primary key (GUID) as the default value.
Custom Partition Id:
It is a value you choose to group related records into a logical partition. For example, in an IoT sensor table, you could use the Device ID as the Partition Id.
Example:
PartitionId = Device-001
Sensor records for that device can use Device-001 as their Partition Id.
Why does it matter with Patch()?
When an elastic table uses a custom Partition Id, you must provide the Partition Id when updating the existing record. The GUID + Partition Id together identify the record.
GUID = ABC123 , PartitionId = Device-001
If the Partition Id is missing or incorrect, Dataverse can’t correctly identify the existing record.
Important: You can’t change a record’s Partition Id after it is created, so choose your partitioning strategy carefully.
Interview tip:
Custom Partition Id → GUID + Partition Id identify the record.
read Microsoft documentation for more details:
https://learn.microsoft.com/en-us/power-apps/developer/data-platform/elastic-tables
https://learn.microsoft.com/en-in/power-apps/developer/data-platform/use-elastic-tables
