diff --git a/codegen/sdk-codegen/aws-models/rds.json b/codegen/sdk-codegen/aws-models/rds.json
index 5a1409c8f7f3..2ea1a3447d9c 100644
--- a/codegen/sdk-codegen/aws-models/rds.json
+++ b/codegen/sdk-codegen/aws-models/rds.json
@@ -10946,7 +10946,7 @@
           }
         },
         "DBShardGroupIdentifier": {
-          "target": "com.amazonaws.rds#String",
+          "target": "com.amazonaws.rds#DBShardGroupIdentifier",
           "traits": {
             "smithy.api#documentation": "<p>The name of the DB shard group.</p>"
           }
@@ -11006,6 +11006,16 @@
         "smithy.api#httpError": 400
       }
     },
+    "com.amazonaws.rds#DBShardGroupIdentifier": {
+      "type": "string",
+      "traits": {
+        "smithy.api#length": {
+          "min": 1,
+          "max": 63
+        },
+        "smithy.api#pattern": "^[a-zA-Z][a-zA-Z0-9]*(-[a-zA-Z0-9]+)*$"
+      }
+    },
     "com.amazonaws.rds#DBShardGroupNotFoundFault": {
       "type": "structure",
       "members": {
@@ -12534,7 +12544,7 @@
       "type": "structure",
       "members": {
         "DBShardGroupIdentifier": {
-          "target": "com.amazonaws.rds#String",
+          "target": "com.amazonaws.rds#DBShardGroupIdentifier",
           "traits": {
             "smithy.api#clientOptional": {},
             "smithy.api#documentation": "<p>Teh name of the DB shard group to delete.</p>",
@@ -15665,7 +15675,7 @@
       "type": "structure",
       "members": {
         "DBShardGroupIdentifier": {
-          "target": "com.amazonaws.rds#String",
+          "target": "com.amazonaws.rds#DBShardGroupIdentifier",
           "traits": {
             "smithy.api#documentation": "<p>The user-supplied DB shard group identifier or the Amazon Resource Name (ARN) of the DB shard group. If this parameter is specified, \n            information for only the specific DB shard group is returned. This parameter isn't case-sensitive.</p>\n         <p>Constraints:</p>\n         <ul>\n            <li>\n               <p>If supplied, must match an existing DB shard group identifier.</p>\n            </li>\n         </ul>"
           }
@@ -22570,7 +22580,7 @@
       "type": "structure",
       "members": {
         "DBShardGroupIdentifier": {
-          "target": "com.amazonaws.rds#String",
+          "target": "com.amazonaws.rds#DBShardGroupIdentifier",
           "traits": {
             "smithy.api#clientOptional": {},
             "smithy.api#documentation": "<p>The name of the DB shard group to modify.</p>",
@@ -25148,7 +25158,7 @@
       "type": "structure",
       "members": {
         "DBShardGroupIdentifier": {
-          "target": "com.amazonaws.rds#String",
+          "target": "com.amazonaws.rds#DBShardGroupIdentifier",
           "traits": {
             "smithy.api#clientOptional": {},
             "smithy.api#documentation": "<p>The name of the DB shard group to reboot.</p>",