Link to 'Special rules for referential actions' from other pages (#4360)

Co-authored-by: Jan Piotrowski <piotrowski+github@gmail.com>
Co-authored-by: Zach Tilev <103522279+zachtil@users.noreply.github.com>

content/200-concepts/100-components/01-prisma-schema/06-relations/410-referential-actions/index.mdx

@@ -349,6 +349,10 @@ When deleting a `User`, its existing posts' `authorUsername` field values will b
 
 When the `username` of a `User` changes, its existing posts' `authorUsername` field values will be set to 'anonymous'.
 
+### Database-specific requirements
+
+MongoDB and SQL Server have specific requirements for referential actions if you have [self-relations](/concepts/components/prisma-schema/relations/referential-actions/special-rules-for-referential-actions#self-relation-sql-server-and-mongodb) or [cyclic relations](/concepts/components/prisma-schema/relations/referential-actions/special-rules-for-referential-actions#cyclic-relation-between-three-tables-sql-server-and-mongodb) in your data model. SQL Server also has specific requirements if you have relations with [multiple cascade paths](/concepts/components/prisma-schema/relations/referential-actions/special-rules-for-referential-actions#multiple-cascade-paths-between-two-models-sql-server-only).
+
 ## Upgrade paths from versions 2.25.0 and earlier
 
 There are a couple of paths you can take when upgrading which will give different results depending on the desired outcome.

content/200-concepts/200-database-connectors/07-mongodb.mdx

@@ -137,23 +137,33 @@ import { ObjectId } from 'bson'
 const id = new ObjectId()
 ```
 
-## Considerations
+## Differences to connectors for relational databases
 
-There are some considerations that come with adopting Prisma into your MongoDB project, these include:
+This section covers ways in which the MongoDB connector differs from Prisma connectors for relational databases.
 
-- Currently no plans to add support for [Prisma Migrate](/concepts/components/prisma-migrate) as MongoDB projects don't rely on internal schemas where changes need to be managed with an extra tool
-  - Management of `@unique` indexes is realized through `db push`
-- [`@@id`](/reference/api-reference/prisma-schema-reference#id-1) and [autoincrement](/reference/api-reference/prisma-schema-reference#generate-auto-incrementing-integers-as-ids) are **not** supported.
+### No support for Prisma Migrate
+
+Currently, there are no plans to add support for [Prisma Migrate](/concepts/components/prisma-migrate) as MongoDB projects do not rely on internal schemas where changes need to be managed with an extra tool. Management of `@unique` indexes is realized through `db push`.
+
+### No support for <inlinecode>@@id</inlinecode> and <inlinecode>autoincrement()</inlinecode>
+
+The [`@@id`](/reference/api-reference/prisma-schema-reference#id-1) attribute (an ID for multiple fields) is not supported because primary keys in MongoDB are always on the `_id` field of a model.
+
+The [`autoincrement()`](/reference/api-reference/prisma-schema-reference#generate-autoincrementing-integers-as-ids) function (which creates incrementing `@id` values) is not supported because `autoincrement()` does not work with the `ObjectID` type that the `_id` field has in MongoDB.
 
 <!--For more information, refer to [Using Prisma with MongoDB](/content/300-guides/050-database/870-using-prisma-with-mongodb.mdx).-->
 
-## Troubleshooting
+### Cyclic references and referential actions
+
+If you have cyclic references in your models, either from self-relations or a cycle of relations between models, and you use [referential actions](/concepts/components/prisma-schema/relations/referential-actions), you must set a referential action of `NoAction` to prevent an infinite loop of actions.
+
+See [Special rules for referential actions](/concepts/components/prisma-schema/relations/referential-actions/special-rules-for-referential-actions) for more details.
 
-### Error: Transactions are not supported by this deployment
+### Replica set configuration
 
 MongoDB only allows you to start a transaction on a replica set. Prisma uses transactions internally to avoid partial writes on nested queries. This means we inherit the requirement of needing a replica set configured.
 
-When you try to use Prisma's MongoDB connector on a deployment that has no replica set configured, you can experience an error message as the following:
+When you try to use Prisma's MongoDB connector on a deployment that has no replica set configured, Prisma shows the message `Error: Transactions are not supported by this deployment`. The full text of the error message is the following:
 
 ```
 PrismaClientUnknownRequestError2 [PrismaClientUnknownRequestError]: