diff --git a/src/pages/[platform]/build-a-backend/data/connect-to-existing-data-sources/connect-postgres-mysql-database/index.mdx b/src/pages/[platform]/build-a-backend/data/connect-to-existing-data-sources/connect-postgres-mysql-database/index.mdx
index b919d0e4a35..016fff09a39 100644
--- a/src/pages/[platform]/build-a-backend/data/connect-to-existing-data-sources/connect-postgres-mysql-database/index.mdx
+++ b/src/pages/[platform]/build-a-backend/data/connect-to-existing-data-sources/connect-postgres-mysql-database/index.mdx
@@ -404,6 +404,7 @@ This allows the Amplify team to maintain and enhance the SQL Layer without needi
 | integer            | a.integer()          |
 | bigint             | a.integer()          |
 | tinyint            | a.integer()          |
+| serial*            | a.integer().default() |
 | float              | a.float()        |
 | double             | a.float()        |
 | decimal            | a.float()        |
@@ -429,6 +430,8 @@ This allows the Amplify team to maintain and enhance the SQL Layer without needi
 | json               | a.json()       |
 | enum               | a.enum()          |
 
+*Support for auto increment (serial) fields is limited to PostgreSQL datasources.
+
 ## Troubleshooting
 
 ### Debug Mode
diff --git a/src/pages/[platform]/build-a-backend/data/data-modeling/add-fields/index.mdx b/src/pages/[platform]/build-a-backend/data/data-modeling/add-fields/index.mdx
index 62688b8f777..6f8f3af1682 100644
--- a/src/pages/[platform]/build-a-backend/data/data-modeling/add-fields/index.mdx
+++ b/src/pages/[platform]/build-a-backend/data/data-modeling/add-fields/index.mdx
@@ -233,6 +233,9 @@ const schema = a.schema({
   }),
 }).authorization((allow) => allow.publicApiKey());
 ```
+
+If you're working with a Postgres datasource, `.default()` can be applied to integer fields to represent [serial fields](/[platform]/build-a-backend/data/connect-to-existing-data-sources/connect-postgres-mysql-database/#mapping-of-sql-data-types-to-field-types-for-auto-generated-schema).
+
 <Callout>
 **Note:** The `.default(...)` modifier can't be applied to required fields.
 </Callout>
diff --git a/src/pages/[platform]/build-a-backend/data/data-modeling/identifiers/index.mdx b/src/pages/[platform]/build-a-backend/data/data-modeling/identifiers/index.mdx
index 0bbaf073608..539d765abc4 100644
--- a/src/pages/[platform]/build-a-backend/data/data-modeling/identifiers/index.mdx
+++ b/src/pages/[platform]/build-a-backend/data/data-modeling/identifiers/index.mdx
@@ -66,8 +66,8 @@ print("New Todo created: \(createdTodo)")
 </InlineFilter>
 
 If you want, you can use Amplify Data to define single-field and composite identifiers:
-- Single-field identifier with a consumer-provided value (type: `id` or `string`, and must be marked `required`)
-- Composite identifier with a set of consumer-provided values (type: `id` or `string`, and must be marked `required`)
+- Single-field identifier with a consumer-provided value (type: `id` or `string` marked `required`, or for a [serial identifier](/[platform]/build-a-backend/data/data-modeling/add-fields/#assign-default-values-for-fields), type: `integer` marked `default`)
+- Composite identifier with a set of consumer-provided values (type: `id` or `string` marked `required`, or for a [serial identifier](/[platform]/build-a-backend/data/data-modeling/add-fields/#assign-default-values-for-fields), type: `integer` marked `default`)
 
 ## Single-field identifier