Preview of the UPSERT Command

This week saw the completion of the AQL UPSERT command. This command will be very helpful in a lot of use cases, including the following:

• ensure that a document exists
• update a document if it exists, otherwise create it
• replace a document if it exists, otherwise create it

The UPSERT command is executed on the server side and so delivers client applications from issuing a fetch command followed by a separate, conditional UPDATE or INSERT command.

The general format of an UPSERT statement is:

UPSERT search-document
INSERT insert-expression
UPDATE update-expression
IN collection-name

Jan collected a few example invocations of UPSERT in his blog.