Updated mapping rules to match new relational schema

Author: dfreniche

docs/60-project-settings.mdx

@@ -7,6 +7,7 @@ import Screenshot from "@site/src/components/Screenshot";
 - Select single inherited primary key. This detects the primary key from the relational schema and sets them as the `_id` in MongoDB.
 - Optionally, toggle Suggested Mappings on and off. 
 
+If we don't do this we'll have both an autogenerated `_id` field of type `ObjectId` and a `id` field copied from the relational DB.
 
 <Screenshot url="https://www.mongodb.com/products/tools/relational-migrator" src="img/90-image-001.png" alt="Screenshot of the connect modal" />
 

docs/80-edit-mapping-rules/10-edit-mapping-books-book-attribute.mdx

@@ -22,15 +22,14 @@ We want to clean up the book_attributes array in our MongoDB schema. We want an
 }
 ```
 
-- On the MongoDB diagram view, click the `books` collection
+- On the MongoDB diagram view, click on the `books` collection.
 - On the relational mappings list on the right, click on the edit icon of `book_attribute` embedded array mapping rule.
-- Change the Field name from `bookAttributes` to `attributes`
-- Uncheck `bookId`. We just want all the attributes, which are key/value pairs.
-- Click `Save and close`
+- Change the Field name from `bookAttributes` to `attributes`.
+- Uncheck `bookId`. We just want all the attributes, which are key/value pairs. Also, as we're embedded inside books, we don't need the `bookId` anymore.
+- Click `Save and close`.
 
 :::info
 Here we've implemented the [Attribute Pattern](https://www.mongodb.com/developer/products/mongodb/attribute-pattern/) for MongoDB. This will allow for easy indexing, querying based on attributes and extension of attributes. 
 :::
 
-<Screenshot url="https://www.mongodb.com/products/tools/relational-migrator" src="img/150-image-001.png" alt="Screenshot of the connect modal" />
-
+<Screenshot url="https://www.mongodb.com/products/tools/relational-migrator" src="img/150-image-001.png" alt="Screenshot of the connect modal" />

docs/80-edit-mapping-rules/100-edit-mapping-issue-detail-issue-detail.mdx

@@ -1,18 +1,17 @@
 import Screenshot from "@site/src/components/Screenshot";
 
-# 🦸 Edit mapping to issueDetails collection (from issue_details table)
+# 🦸 Remove unnecessary ids from issueDetails
 
 :::info
 Extra activity! Do it if you have extra time or are following along at home. It won't be covered during the hands-on lab.
 :::
 
-Now we want to remove some unncessary id fields from the issueDetails collection 
+Now we want to remove some unncessary id fields from the issueDetails collection. We have `bookId` and `userId` but we also have these values in the embedded `book` and `user` fields.
 
-
-- On the MongoDB diagram view, click the `issueDetails` collection
-- On the relational mappings list on the right, click on the edit icon of `issue_details` New Documents mapping rule
+- On the MongoDB diagram view, click the `issueDetails` collection.
+- On the relational mappings list on the right, click on the edit icon of `issue_details` New Documents mapping rule.
 - Uncheck the `bookId` and `userId` fields, and leave all other fields checked.
-- Click `Save and close`
+- Click `Save and close`.
 
 
 

docs/80-edit-mapping-rules/110-add-mapping-reviews-user.mdx

@@ -1,20 +1,20 @@
 import Screenshot from "@site/src/components/Screenshot";
 
-# 🦸 Add mapping to reviews collection (from users table)
+# 🦸 Add user's names to reviews
 
 :::info
 Extra activity! Do it if you have extra time or are following along at home. It won't be covered during the hands-on lab.
 :::
 
 We want to store each user's name against their reviews.
 
-- On the MongoDB diagram view, click the `reviews` collection
-- On the relational mappings list on the right, click `+Add`
-- Select `Embedded documents`
-- Select `users` as Source table
-- In the advanced settings check `Merge fields into the parent`
-- Only check `name` field
-- Click `Save and close `
+- On the MongoDB diagram view, click the `reviews` collection.
+- On the relational mappings list on the right, click `+Add`.
+- Select `Embedded documents`.
+- Select `users` as Source table.
+- In the advanced settings check `Merge fields into the parent`.
+- Only check `name` field.
+- Click `Save and close`.
 
 
 <Screenshot url="https://www.mongodb.com/products/tools/relational-migrator" src="img/200-image-001.png" alt="Screenshot of the connect modal" />

docs/80-edit-mapping-rules/120-users-addresses.mdx

@@ -0,0 +1,30 @@
+import Screenshot from "@site/src/components/Screenshot";
+
+# 🦸 Clean Users address data
+
+:::info
+Extra activity! Do it if you have extra time or are following along at home. It won't be covered during the hands-on lab.
+:::
+
+The array that holds user addresses has a lot of unneeded data.
+
+- On the MongoDB diagram view, click on the `users` collection
+- Click on the edit edit icon of `userAddresses`
+- Change the field name from `userAddresses` to `addresses`.
+- Deselect `id`, `userId` and `cityId`.
+- Click `Save and close `
+- Click on the edit edit icon of `cities`, which is an embedded document inside the array `addresses`.
+- Deselect `id`.
+- Rename the `name` field into `cityName`.
+- In the advanced settings, check 'Merge fields into parent`.
+- Click `Save and close`.
+- On the relational mappings list on the right, click `+Add`.
+- Select `Embedded documents`.
+- Select `countries` as Source table.
+- In the advanced settings check `Merge fields into the parent`.
+- Only check `name` field, renaming the `name` field into `countryName`.
+- Click `Save and close`.
+
+
+![Screenshot of the users collection](/img/users.png)
+

docs/80-edit-mapping-rules/20-edit-mapping-books-book-genre.mdx

@@ -9,28 +9,32 @@ We'll go from the proposed array of objects:
 ```json
 bookGenres: [
     {
-        bookId: "Some Book Id",
-        genres: "fiction"
+        "bookId": "Some Book Id",
+        "genres": "fiction"
     },
     {
-        bookId: "Some Book Id",
-        genres: "novel"
+        "bookId": "Some Book Id",
+        "genres": "novel"
     }
 ]
 ```
 
-to an array of primitive values
+to an array of
 
 ```json
-genres: [ "fiction", "novel" ]
+genres: [ 
+    { "name": "fiction" }, 
+    { "name" :"novel" } 
+]
 ```
 
-- On the MongoDB diagram view, click the `books` collection
-- On the relational mappings list on the right, click on the edit icon of `book_genre` embedded array
-- Change the field name from `bookGenres` to `genres`
-- Uncheck `bookId`
-- In the advanced settings, check `create array of primitive values`
-- Click `Save and close`
+- On the MongoDB diagram view, click the `books` collection.
+- Click on the edit edit icon of `genres`. Deselect `id`, This is a child relationship of `bookGenres`, and we'll merge these fields into the parent, to avoid too much unneccesary nesting.
+- Click `Save and close`.
+- Click on the edit icon of the `book_genre` embedded array.
+- Change the field name from `bookGenres` to `genres`.
+- Uncheck `bookId` and `genreId`.
+- Click `Save and close`.
 
 
 

docs/80-edit-mapping-rules/30-add-mapping-books-authors.mdx

@@ -2,20 +2,47 @@ import Screenshot from "@site/src/components/Screenshot";
 
 # 👐 Add authors details to the books collection
 
-We want to modify the MongoDB schema so that each book contains an array of its authors.
-In this step we will embed the book details into the empty array created from the join table (which right now only contains `authorId` and `bookId`)
+## 👐 Add author name to the books collection
+
+We want to modify the MongoDB schema so that each book contains an array of its authors. Right now in the `authorBooks` mapping we're getting the `authorId` for the current book, but we want also the name of the author. So in this step we will embed the author name into array created from the mapping of the join table (which right now only contains `authorId` and `bookId`)
 
 - On the MongoDB diagram view, click the `books` collection
 - On the relational mappings list on the right, click `+ Add`
 - Select `Embedded documents`
 - Select `authors` as Source table
 - In the advanced settings, check 'Merge fields into parent`
-- Check the `id` and `name` fields and uncheck the rest
+- Check the `name` field and uncheck the rest
 - Click `Save and close` 
 
-:::info
-This is a perfect example of the [Extended Reference Pattern](https://www.mongodb.com/blog/post/building-with-patterns-the-extended-reference-pattern). When we read a book, we have some of the author's data (`name` in this case) but we still have the author's id in case we need all the author's attributes (we can then do a join on read using `$lookup`)
-:::
 
 <Screenshot url="https://www.mongodb.com/products/tools/relational-migrator" src="img/130-image-001.png" alt="Screenshot of the connect modal" />
 
+## 👐 Remove unneeded bookId from author details in books collection
+
+We want to modify the MongoDB schema so that each book contains an array of its authors.
+In this step we will remove the redundant ID fields from the join table. 
+
+- On the MongoDB diagram view, click the `books` collection.
+- On the relational mappings list on the right, click on the edit icon of `author_book`.
+- Edit the field name from `authorBooks` to just `authors`.
+- In the list of fields, uncheck `bookId`. 
+- Click `Save and close`.
+
+This results in our `authors` array looking like:
+
+```json
+    "authors": [
+        {
+            "authorId": 8282,
+            "name": "Cervantes"
+        },
+        ...
+    ]
+```
+
+<Screenshot url="https://www.mongodb.com/products/tools/relational-migrator" src="img/140-image-001.png" alt="Screenshot of the connect modal" />
+
+
+:::info
+This is a perfect example of the [Extended Reference Pattern](https://www.mongodb.com/blog/post/building-with-patterns-the-extended-reference-pattern). When we read a book, we have some of the author's data (`name` in this case) but we still have the author's id in case we need all the author's attributes (we can then do a join on read using [`$lookup`](https://www.mongodb.com/docs/manual/reference/operator/aggregation/lookup/))
+:::

docs/80-edit-mapping-rules/40-edit-mapping-books-author-book.mdx

@@ -10,15 +10,15 @@ This is an implementation of the [Subset Pattern](https://www.mongodb.com/blog/p
 
 In this step we will embed the book details into the empty array from the join table. 
 
-- On the MongoDB diagram view, click the `books` collection
-- On the relational mappings list on the right, click `+ Add`
-- Select `Embedded array`
-- Select `reviews` as Source table
-- In the advanced settings, check `Add array conditions`
-- In `Sort by and order` option, select `timestamp` and toggle the order to descending
-- Set `Limit number of rows` to `3`
-- Uncheck the `bookId` and leave the rest of the fields checked
-- Click `Save and close` 
+- On the MongoDB diagram view, click the `books` collection.
+- On the relational mappings list on the right, click `+ Add`.
+- Select `Embedded array`.
+- Select `reviews` as Source table.
+- In the advanced settings, check `Add array conditions`.
+- In `Sort by and order` option, select `timestamp` and toggle the order to descending.
+- Set `Limit number of rows` to `3`.
+- Uncheck the `bookId` and leave the rest of the fields checked.
+- Click `Save and close`.
 
 Limitations: 
 - Continuous Migration Mode will not support this transformation

docs/80-edit-mapping-rules/50-add-mapping-books-reviews.mdx

@@ -1,14 +1,14 @@
 import Screenshot from "@site/src/components/Screenshot";
 
-# 👐 Add aliases to authors
+# 👐 Edit author's aliases array
 
 We want to modify the MongoDB schema so that each author's aliases are represented as an array of strings. 
 
-- On the MongoDB diagram view, click the `authors` collection
-- On the relational mappings list on the right, click on the edit icon of `author_alias` embedded array mapping rule
-- In the list of fields, uncheck `authorId`
-- In the mapping rule's advanced settings, Check `create array of primitive values`
-- Click `Save and close`
+- On the MongoDB diagram view, click on the `authors` collection.
+- On the relational mappings list on the right, click on the edit icon of `author_alias` embedded array mapping rule.
+- In the list of fields, uncheck `authorId`.
+- In the mapping rule's advanced settings, Check `create array of primitive values`.
+- Click `Save and close`.
 
 <Screenshot url="https://www.mongodb.com/products/tools/relational-migrator" src="img/110-image-001.png" alt="Screenshot of the connect modal" />