-committed (e.g. due to I/O errors), then "result" will have one more
-element than "params", with the additional element describing the
-error.
+committed, then "result" will have one more element than "params",
+with the additional element an <error>. The possible "error" strings
+include at least the following:
+
+ "error": "referential integrity violation"
+
+ When the commit was attempted, a column's value referenced the
+ UUID for a row that did not exist in the table named by the
+ column's <base-type> key or value "refTable". (This can be
+ caused by inserting a row that references a nonexistent row,
+ by deleting a row that is still referenced by another row, by
+ specifying the UUID for a row in the wrong table, and other
+ ways.)