{NOTE: }
-
There are situations where new fields are added to some documents in a collection over time.
-
To find the documents that are missing the newly added fields you can either:
{NOTE/}
{PANEL: Query the collection (dynamic query)}
To run a dynamic query over a collection and find which documents are missing a specified field,
use the not and whereExists extension methods, accessible from the query API,
as shown below.
This will either create a new auto-index or add the queried field to an existing auto-index.
Learn more about the dynamic query flow here.
Example
{CODE-TABS}
{CODE-TAB:nodejs:DocumentQuery whereNotExists_1@client-api\session\Querying\filterByNonExistingField.js /}
{CODE-TAB-BLOCK:sql:RQL}
from "orders"
where true and not exists("freight")
// not cannot be used immediately after where, thus we use where true.
{CODE-TAB-BLOCK/}
{CODE-TABS/}
{PANEL/}
{PANEL: Query a static index}
Documents with missing fields can be searched by querying a static index.
The index definition must contain the following document fields indexed:
- A document field that exists in all documents of the queried collection, e.g. the Id field.
Indexing this field will ensure that all the documents of this collection are indexed. - A document field that is suspected to be missing from some documents of the queried collection.
Example
{CODE:nodejs the_index@client-api\session\Querying\filterByNonExistingField.js /}
{CODE-TABS}
{CODE-TAB:nodejs:DocumentQuery whereNotexists_2@client-api\session\Querying\filterByNonExistingField.js /}
{CODE-TAB-BLOCK:sql:RQL}
from index "Orders/ByFreight"
where true and not exists("freight")
// not cannot come immediately after where, thus we use where true.
{CODE-TAB-BLOCK/}
{CODE-TABS/}
{PANEL/}
{PANEL: Use Studio to Run an RQL Query}
-
Documents can be searched by missing fields using Studio's Query view.
-
Use an RQL expression such as: {CODE-BLOCK:sql} from "Orders"
where exists("Company") and not exists("Freight") {CODE-BLOCK/} -
In the
whereclause:
First search for a field that exists in all documents of the queried collection, e.g. the Id field.
Then search for a field that may be missing from some documents of the queried collection.
- Indexes
Click to see the Indexes menu. - Query
Select to open the Query view. - Query editor
Write the RQL query. - Run Query
Click to run the query. - Index used
The name of the auto-index created to serve this query.
You can click it to see the available Studio options for this index. - Results
This is the list of documents that do not contain the specified 'Freight' field.
(the "Freight" Field was removed from these Northwind documents for this example.)
- Indexes
{PANEL/}