LDC-Q2007 — The row has no field under that name

What it means

Dotted reads walk into structured rows field by field, and each field must exist on the row. A step that names no known field stops the query, and the engine lists the fields the row does have, so a typo is easy to spot. A field the snapshot knows but this row lacks reads as empty instead — this code is only for names the snapshot never heard of.

Use one of the listed field names, or check the spelling against them.

Example

Both queries below run against this package:

Arxo Law

language "law.core" version "0.2";
package demo.diagnostics version "0.1.0";
namespace "urn:law:demo:diagnostics";

entity Applicant;
relation resident(a: Applicant) kind institutional;
relation permit_eligible(a: Applicant) kind institutional;

rule PermitEligibility strict {
    for a: Applicant;
    when resident(a);
    then permit_eligible(a);
}

No rule row carries this field:

LawQL

from r in rules where r.zzz9 == 1 select r

Fix

LawQL

from r in rules select r

Engine message

The engine reports this in its own wording:

Output

LDC-Q2007: unknown field 'zzz9' on r. Hint: fields: id, strength, head_predicate, head_polarity, head_variables, body_variables, body_predicates, package, path

Related

• Questions to the engine — how sources bind names.
• LDC-Q2006 — when the value itself has no fields.