Operators for "AddPostProcessing"

[This is preliminary documentation and subject to change.]

DBOP_prior_command_tree

Used when adding post-processing operations. This operator occurs in the post-processing tree but never in a complete command tree. No inputs, table- or scalar-valued, depending on the previous command tree.

DBOP_add_columns

Used when adding post-processing operations, this operation is the only operation that can add columns "projected away" by earlier operations, i.e. columns from tables that already participate in the query. The inputs are a table and a projection list. The output is a table.