Module mz_sql::query_model::attribute::relation_type

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Expand description

Defines the RelationType attribute.

The attribute value is a vector of ColumnType associated with the output boxes of each query box.

To derive Model::cols_type we need to derive Model::expr_type for each column expression in that box. To derive the Model::expr_type, we need to derive Model::cref_type, which in turn requires deriving Model::cols_type on the input box of the quantifier associated with the Model::cref_type argument.

Derivation therefore must proceed in a bottom-up manner.

The implementation makes use of the derived attributes RejectedNulls as follows: If a ColumnReference cannot be null if the enclosing box rejects nulls for it.

Structs

RelationType 🔒

Functions

intersect_rejects_nulls 🔒
A quantifier referenced the given ColumnReference introduces nulls if:
outer_join_introduces_nulls 🔒
A quantifier referenced the given ColumnReference introduces nulls if:
select_rejects_nulls 🔒
A ColumnReference rejects nulls if:
union_introduces_nulls 🔒
A quantifier referenced the given ColumnReference introduces nulls if: