Please discuss the concept of history preserving.

Even though it is usually better to answer technical questions directly and succinctly, some questions may need more detailed answers. This is true for complex concepts, lengthy processes, or terminology which cannot easily be defined. Keep in mind that the common rules for interviewing are simply guidelines. You should know when you can go beyond these to provide the answer the interviewer seeks.

"History preserving is the process of providing a new row in the target instead of updating an existing row. The columns in the target will indicate which transformations are to be preserved. The new rows will be created when the value of a certain column changes and will be flagged as Update, which is applied to the input data set."