[CALCITE-465] Remove OneRow and Empty relational expressions; Values will suffice

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.0.0-incubating
• Assignee: Julian Hyde
• Reporter: Julian Hyde
• Created: 14/Nov/14 21:25
• Updated: 08/Feb/15 08:56
• Resolved: 14/Nov/14 22:23

Description

The OneRow and Empty relational expressions do not give any descriptive power over a Values relational expression with 1 tuple and 0 tuples, respectively. We should remove them (and their sub-classes).

Now that RelOptRuleOperand can take a Predicate, it is easy to write rules that match a Values that has zero tuples.

Benefits include efficiency (the planning process will creature fewer relational expressions) and rule re-use (rules applicable to Values are now automatically applicable to 1- and 0-row relational expressions).