A system and method for updating collection-valued and other complex
structured columns in a nested table using a nested extension of an
UPDATE statement that is analogous to the syntax and semantics of the
UPDATE statement that is used to modify scalar-valued columns of the
table (called the outer UPDATE). Using the same syntactic and semantic
constructs as the table at the outer level allows an existing
implementation that processes modifications to relational tables to reuse
its implementation techniques for processing outer updates to modify
collection-valued columns as well. The UPDATE extensions enable the
specification of updates to nested collections embedded at arbitrary
levels of depth in the object model. The new syntax is embedded inside
the outer UPDATE statement in a way that parallels the structure of the
data itself and thus maps more directly to the user's conceptual model of
the data.