Whether how a node runs depends on the database type: a Drop, a Slice, a Limit or a Distinct, which some databases take another way (PLAN §11.4); a Pivot or an Explode Array, which some can't run (§11.12, §11.20); a filter or an Extend that gives % or _ to a pattern (givesPatternWildcard, §11.11), or a pattern that isn't a literal (givesNonLiteralPattern, §11.14). The one rule for when Cube needs the database type.