How to query and remove deleted data in Couchbase?

Couchbase is a distributed NoSQL database that supports data querying and deletion operations using N1QL, which is similar to SQL.

To search for deleted data, you can follow these steps:

1. Open the Couchbase Web console and log in to your cluster.
2. Choose the bucket you want to query.
3. In the search tab, input the following N1QL query, replacing bucket_name and fields_to_retrieve with the name of the bucket and fields you want to retrieve.

SELECT META(bucket_name).id, *
FROM bucket_name
WHERE META(bucket_name).deleted = true

This query will return all deleted documents and their metadata. You can modify the query criteria as needed.

To delete data, you can follow these steps:

1. Open the Couchbase Web console and log in to your cluster.
2. Select the bucket from which you want to delete data.
3. In the search tab, enter the following N1QL query, replacing bucket_name and where_clause with the name and condition of the bucket you want to delete.

DELETE FROM bucket_name WHERE where_clause

For example, to delete all deleted documents, you can use the following query.

DELETE FROM bucket_name WHERE META(bucket_name).deleted = true

This query will delete all documents that meet the condition. Please use the delete operation carefully to avoid unintentionally deleting important data.

Please note that N1QL queries and delete operations can be executed within an application either through the Couchbase SDK or using the Couchbase REST API.