Data Modeling

Property prefix

User properties cannot begin with an underscore (_).

The underscore character (_) is a reserved prefix for system properties of a document (_id, _rev etc.) A document which contains user properties with a leading underscore will be rejected by Sync Gateway with the following error.

"{"error":"Bad Request","reason":"user defined top level properties beginning with '_' are not allowed in document body"}"

This rule applies to writes performed through Couchbase Lite SDKs and Sync Gateway REST APIs. And to writes performed through Couchbase SDKs when Mobile-Web Data Sync is enabled.

This may be an issue in the following scenarios:

In a deployment with Mobile-Web Data Sync and Field Level Encryption enabled, this rule conflicts with the default field encryption format.
Ottoman.js adds an _type attribute to the root of the document. So if you are using Ottoman within your app, then you would encounter this issue.

Note that in a deployment with Mobile-Web Data Sync and Field Level Encryption enabled, this rule conflicts with the default field encryption format.

Workaround

The recommended workaround in these scenarios is to wrap the property prefixed with an underscore in another object whose key isn’t prefixed with an underscore.