Run the following command on your SQL database to update a couple of rows in the source table. This stored procedure is used to update the watermark table when new rows have been extracted.ĬREATE PROCEDURE sp_write_watermark datetime, varchar(50) In this example, the table name SalesOrderDetail.Ĭreate a stored procedure in our SQL Database: Set the default value of the watermark with the name of our source table. Run the following command in your SQL Database to create a table named watermark that will store our watermark value: Run the following SQL in your created database to create a staging version of the SalesOrderDetails table:ĬREATE TABLE. We therefore need to create a target or “staging” table to load our delta rows into. In this example, we’ll use the SalesOrderDetail table in the AdventureWorksLT database: SalesOrderDetailĪnd we will use the ModifiedDate as the watermark column. Create a stored procedure that updates the watermark value, ready for the next run.īuilding the Solution Create a Staging Table.These delta rows are then written to our target table. Create a Copy activity copies rows from the source where any watermark values are greater than the old watermark value.The first looks up the last watermark value and the second retrieves the current watermark value. Create a pipeline that does the following:.Create a data store to hold the watermark value. In this example we store the watermark value in our SQL Database.We use the maximum value of this column as the watermark. Modified_Date_Time) or an ever increasing integer. This column is normally an automatically updating datetime column (e.g. This column is one that can be used to filter new or updated records for each run. In the Data Factory documentation this is referred to as the Watermark column so I’ll use this latter term for consistency going forwards. There are four main steps to this process to create an end to end incremental extract. The diagram demonstrates a high level overview of the process, and should be familiar to those who have built similar data flows with other ETL tools such as SSIS: Incremental Loading Overview Process That’s it! Incremental Loading in Data Factory v2
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