Hi @Govind3331, Handling incremental data without a primary key or date column can be challenging, but there are some strategies you can consider.
Row Number Approach:
- You can use the ROW_NUMBER() function to assign a unique number to each row based on a specific order (e.g., timestamp or any other column). Then, select the rows with the highest row number to get the latest records.
- Here’s an example query:WITH CTE AS ( SELECT *, ROW_NUMBER() OVER (ORDER BY YourTimestampColumn DESC) AS rn FROM YourTableName ) SELECT * FROM CTE WHERE rn = 1;
- Replace YourTimestampColumn with the appropriate column name that represents the order of data arrival (e.g., timestamp, sequence number, etc.).
Comparison with Previous Load:
- If you have a previous load of data in your BRONZE layer, you can compare it with the new data.
- For each record in the new data, check if it already exists in the BRONZE layer. If not, it’s an incremental record.
- This approach requires maintaining a copy of the previous load.
Hashing Approach:
- Calculate a hash value for each row based on the column values (excluding any unique identifiers).
- Store the hash values for the existing records in the BRONZE layer.
- When new data arrives, calculate the hash for each row and compare it with the stored hashes. If it’s a new hash, it’s an incremental record.
- Note that this approach may have performance implications.
Change Data Capture (CDC):
- CDC is a feature in SQL Server that captures changes made to tables.
- Even without a primary key, you can enable CDC on the table and track changes (inserts, updates, deletes).
- The captured changes can be used to identify incremental records.
