For simplicity, consider the following common scenario: An i Series has multiple item tables holding data related in a one-to-one relationship.
Often, this scenario is due to multiple application packages having item master files that are both populated with common item data.
The MERGE statement is structured to handle all three operations, INSERT, UPDATE, and DELETE, in one command. When you read the UPDATE statement, the key items are scattered.
Here are a few more thoughts on programming: You can build as much logic as necessary into your views. Weight Is Not Null Then Insert Into Item Ext Values(Item View New.
For example, if our ITEMVIEW view was re-created with a LEFT OUTER JOIN, we could easily enhance the trigger code to use something like this to optionally insert a row into the item extension table only if one or more column values were present: If Item View New.
For example, inserting a row if it does not exist, or updating the row if it does match. Color WHEN NOT MATCHED BY TARGET THEN INSERT (Product ID, Name, Product Number, Color) VALUES (S. Given the complex nature of the MERGE command’s match condition, it can result in more overhead to process the source and target rows.
When simply updating one table based on the rows of another table, improved performance and scalability can be achieved with basic INSERT, UPDATE, and DELETE statements. However, when you need to do more than one operation, the MERGE command is most likely a better choice, as you are only making one pass through the data as opposed to multiple passes, one for each separate UPDATE, INSERT, or DELETE command, through the source data. If so, I would recommend ready my article Introduction to SQL Server Data Modification Statements.
By creating INSTEAD OF triggers on update and insert events, view ITEMVIEW will become fully modifiable. Item Type); Insert Into Item Ext Values(Item View New. The form would not be nearly as effective if it showed, for example, only the item extension data.