When you specify a relational source table in the dataflow, Data Services executes simple SQL SELECT
statements in the background to fetch the data. If you want to, you can see the list of statements executed for each source table. In this recipe, we explore what happens under the hood when you add multiple source tables and how Data Services optimizes the extraction of the data from these source tables and even joins them together, executing complex SQL queries instead of multiple SELECT * FROM <table>
.
In this recipe, we will extract a person's name, address, and phone number from the source OLTP database and populate a new stage table PERSON_DETAILS with this data set.
Create a new job and a new dataflow. Specify your own names for the created objects.
To extract the required data, you will need to import the tables
PERSON
,ADDRESS
, andBUSINESSENTITYADDRESS
(which is a table linking the first two) into your source OLTP...