Functions that build provenance circuit gates for semiring operations. More...

Functions
UUID	provsql.provenance_times (UUID[] tokens)
	Create a times (product) gate from multiple provenance tokens.

UUID	provsql.provenance_monus (UUID token1, UUID token2)
	Create a monus (difference) gate from two provenance tokens.

UUID	provsql.provenance_project (UUID token, INT[] positions)
	Create a project gate for where-provenance tracking.

UUID	provsql.provenance_eq (UUID token, INT pos1, INT pos2)
	Create an equijoin gate for where-provenance tracking.

UUID	provsql.provenance_plus (UUID[] tokens)
	Create a plus (sum) gate from an array of provenance tokens.

UUID	provsql.provenance_cmp (UUID left_token, OID comparison_op, UUID right_token)
	Create a comparison gate for HAVING clause provenance.

Detailed Description

Functions that build provenance circuit gates for semiring operations.

These are called internally by the query rewriter.

Function Documentation

Create a comparison gate for HAVING clause provenance.

Parameters

left_token	provenance token for the left operand
comparison_op	OID of the comparison operator
right_token	provenance token for the right operand

Create an equijoin gate for where-provenance tracking.

Parameters

token	child provenance token
pos1	attribute index in the first relation
pos2	attribute index in the second relation

UUID provsql.provenance_monus	(	UUID	token1,
		UUID	token2
	)

Create a monus (difference) gate from two provenance tokens.

Implements m-semiring monus. Returns token1 if token2 is NULL (used for LEFT OUTER JOIN semantics in the EXCEPT rewriting).

UUID provsql.provenance_plus ( UUID[] tokens )

Create a plus (sum) gate from an array of provenance tokens.

Filters out NULL and zero-gates; returns gate_zero() if all tokens are trivial, or a single token if only one remains.

UUID provsql.provenance_project	(	UUID	token,
		INT[]	positions
	)

Create a project gate for where-provenance tracking.

Records the mapping between input and output attribute positions.

Parameters

token	child provenance token
positions	array encoding attribute position mappings

UUID provsql.provenance_times ( UUID[] tokens )

Create a times (product) gate from multiple provenance tokens.

Filters out NULL and one-gates; returns gate_one() if all tokens are trivial, or a single token if only one remains.