cayleygraph/cayley · error

error executing value lookup

Error message

error executing value lookup: %w

What it means

NameOf performs a SELECT against the values table scanning string/bool/int/float/time columns to reconstruct the quad.Value. If the query fails for a reason other than ErrNoRows, it is wrapped as this error, so the underlying SQL error (connection loss, bad schema, locked table) is the cause.

Solutions

1. Check the wrapped cause with errors.Unwrap / %w to see the driver error
2. Verify the database schema matches the version expected by this quadstore (run migrations)
3. Test DB connectivity and credentials
4. Re-create or repair the values table if it is missing or corrupt

Example fix

// before
val, err := qs.NameOf(h) // opaque failure
// after
val, err := qs.NameOf(h)
if err != nil { log.Printf("cause: %v", errors.Unwrap(err)) }

val, err := qs.NameOf(h)
var cause error
for e := err; e != nil; e = errors.Unwrap(e) { cause = e }
if err != nil && cause != sql.ErrNoRows {
    // log cause; check DB connectivity/schema before retrying
}

When it happens

Trigger: Querying the values table when the DB connection is broken, the table doesn't exist or schema was migrated manually, or a driver-level error occurs during Scan.

Common situations: Schema version mismatch after upgrading Cayley without running migration; dropped/renamed values table; transient network errors between app and database.

Understand the failure class

Background: Database query failed: Internal Server Error 500s wrapping SQL, Prisma, and connection failures — what to check first — this error's family across 16 libraries.

Related errors

• sql query failed: query
• unmarshal value
• unsupported sql database
• unsupported time format: %T
• cannot find node hash in query output

AI-assisted analysis of cayleygraph/cayley@81dcd7d73e (2026-09-06). Data as JSON: /api/errors/ca3fa546e23a42c1. Report an issue: GitHub.

Appendix: source

Thrown at graph/sql/quadstore.go:693

	} else {
		vtimeScan = &vtimeStd
		vtimeTime = &vtimeStd.Time
		vtimeValid = &vtimeStd.Valid
	}
	if err := c.Scan(
		&data,
		&str,
		&typ,
		&lang,
		&iri,
		&bnode,
		&vint,
		&vbool,
		&vfloat,
		vtimeScan,
	); err != nil {
		if err != sql.ErrNoRows {
			return nil, fmt.Errorf("error executing value lookup: %w", err)
		}
	}
	var val quad.Value
	if str.Valid {
		if iri.Bool {
			val = quad.IRI(str.String)
		} else if bnode.Bool {
			val = quad.BNode(str.String)
		} else if lang.Valid {
			val = quad.LangString{
				Value: quad.String(unescapeNullByte(str.String)),
				Lang:  lang.String,
			}
		} else if typ.Valid {
			val = quad.TypedString{
				Value: quad.String(unescapeNullByte(str.String)),
				Type:  quad.IRI(typ.String),
			}

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