Add onlyUpdate flag to loadUpdateData

Description

From https://github.com/liquibase/liquibase/pull/307

Adding onlyUpdate flag to loadUpdateData for cases where we want to only update existing records. This allows the use of the tag in a way that only columns we need will be updated and prevents failures if a record is unexpectly absent from the target database. (Due to insufficient fields in the input file.)

Environment

All

Reporter

Nathan Voxland

Fix versions

Affects versions

Priority

Major
Configure