src/main/java/com/conveyal/gtfs/loader/Table.java
public String generateUpdateSql (String namespace, int id) {
        // Collect field names for string joining from JsonObject.
        String joinedFieldNames = editorFields().stream()
                // If updating, add suffix for use in set clause
                .map(field -> field.name + " = ?")
                .collect(Collectors.joining(", "));

        String tableName = namespace == null ? name : String.join(".", namespace, name);
        return String.format("update %s set %s where id = %d", tableName, joinedFieldNames, id);
    }
public String generateUpdateSql (String namespace, int id) {
        // Collect field names for string joining from JsonObject.
        String joinedFieldNames = editorFields().stream()
                // If updating, add suffix for use in set clause
                .map(field -> field.name + " = ?")
                .collect(Collectors.joining(", "));

        String tableName = namespace == null ? name : String.join(".", namespace, name);
        return String.format("update %s set %s where id = %d", tableName, joinedFieldNames, id);
    }
Create SQL string for use in update statement. Note, this filters table's fields to only those used in editor.