diff --git a/docs/site/Controller-generator.md b/docs/site/Controller-generator.md
index 7ab29ddf96cc..5d97d783f189 100644
--- a/docs/site/Controller-generator.md
+++ b/docs/site/Controller-generator.md
@@ -169,10 +169,17 @@ export class TodoController {
     },
   })
   async updateAll(
-    @requestBody() data: Todo,
+    @requestBody({
+      content: {
+        'application/json': {
+          schema: getModelSchemaRef(Todo, {partial: true}),
+        },
+      },
+    })
+    todo: Partial<Todo>
     @param.query.object('where', getWhereSchemaFor(Todo)) where?: Where<Todo>,
   ): Promise<number> {
-    return await this.todoRepository.updateAll(data, where);
+    return await this.todoRepository.updateAll(todo, where);
   }
 
   @get('/todos/{id}', {
@@ -196,9 +203,16 @@ export class TodoController {
   })
   async updateById(
     @param.path.number('id') id: number,
-    @requestBody() data: Todo,
+    @requestBody({
+      content: {
+        'application/json': {
+          schema: getModelSchemaRef(Todo, {partial: true}),
+        },
+      },
+    })
+    todo: Partial<Todo>,
   ): Promise<void> {
-    await this.todoRepository.updateById(id, data);
+    await this.todoRepository.updateById(id, todo);
   }
 
   @del('/todos/{id}', {
diff --git a/docs/site/tutorials/todo-list/todo-list-tutorial-controller.md b/docs/site/tutorials/todo-list/todo-list-tutorial-controller.md
index 367e174982eb..321a69b006f2 100644
--- a/docs/site/tutorials/todo-list/todo-list-tutorial-controller.md
+++ b/docs/site/tutorials/todo-list/todo-list-tutorial-controller.md
@@ -256,7 +256,14 @@ export class TodoListTodoController {
   })
   async patch(
     @param.path.number('id') id: number,
-    @requestBody() todo: Partial<Todo>,
+    @requestBody({
+      content: {
+        'application/json': {
+          schema: getModelSchemaRef(Todo, {partial: true}),
+        },
+      },
+    })
+    todo: Partial<Todo>
     @param.query.object('where', getWhereSchemaFor(Todo)) where?: Where<Todo>,
   ): Promise<Count> {
     return await this.todoListRepo.todos(id).patch(todo, where);
diff --git a/examples/express-composition/src/controllers/note.controller.ts b/examples/express-composition/src/controllers/note.controller.ts
index 84fc7fa85726..6d9f7a98773c 100644
--- a/examples/express-composition/src/controllers/note.controller.ts
+++ b/examples/express-composition/src/controllers/note.controller.ts
@@ -14,6 +14,7 @@ import {
   del,
   get,
   getFilterSchemaFor,
+  getModelSchemaRef,
   getWhereSchemaFor,
   param,
   patch,
@@ -84,7 +85,14 @@ export class NoteController {
     },
   })
   async updateAll(
-    @requestBody() note: Note,
+    @requestBody({
+      content: {
+        'application/json': {
+          schema: getModelSchemaRef(Note, {partial: true}),
+        },
+      },
+    })
+    note: Partial<Note>,
     @param.query.object('where', getWhereSchemaFor(Note)) where?: Where<Note>,
   ): Promise<Count> {
     return await this.noteRepository.updateAll(note, where);
@@ -111,7 +119,14 @@ export class NoteController {
   })
   async updateById(
     @param.path.number('id') id: number,
-    @requestBody() note: Note,
+    @requestBody({
+      content: {
+        'application/json': {
+          schema: getModelSchemaRef(Note, {partial: true}),
+        },
+      },
+    })
+    note: Partial<Note>,
   ): Promise<void> {
     await this.noteRepository.updateById(id, note);
   }
diff --git a/examples/todo-list/src/controllers/todo-list-todo.controller.ts b/examples/todo-list/src/controllers/todo-list-todo.controller.ts
index 0cdae05ccae7..b2e25cdb64b8 100644
--- a/examples/todo-list/src/controllers/todo-list-todo.controller.ts
+++ b/examples/todo-list/src/controllers/todo-list-todo.controller.ts
@@ -13,6 +13,7 @@ import {
 import {
   del,
   get,
+  getModelSchemaRef,
   getWhereSchemaFor,
   param,
   patch,
@@ -71,7 +72,14 @@ export class TodoListTodoController {
   })
   async patch(
     @param.path.number('id') id: number,
-    @requestBody() todo: Partial<Todo>,
+    @requestBody({
+      content: {
+        'application/json': {
+          schema: getModelSchemaRef(Todo, {partial: true}),
+        },
+      },
+    })
+    todo: Partial<Todo>,
     @param.query.object('where', getWhereSchemaFor(Todo)) where?: Where<Todo>,
   ): Promise<Count> {
     return await this.todoListRepo.todos(id).patch(todo, where);
diff --git a/examples/todo-list/src/controllers/todo-list.controller.ts b/examples/todo-list/src/controllers/todo-list.controller.ts
index 443a20ac553c..ebac19f52ce9 100644
--- a/examples/todo-list/src/controllers/todo-list.controller.ts
+++ b/examples/todo-list/src/controllers/todo-list.controller.ts
@@ -88,11 +88,18 @@ export class TodoListController {
     },
   })
   async updateAll(
-    @requestBody() obj: Partial<TodoList>,
+    @requestBody({
+      content: {
+        'application/json': {
+          schema: getModelSchemaRef(TodoList, {partial: true}),
+        },
+      },
+    })
+    todoList: Partial<TodoList>,
     @param.query.object('where', getWhereSchemaFor(TodoList))
     where?: Where<TodoList>,
   ): Promise<Count> {
-    return await this.todoListRepository.updateAll(obj, where);
+    return await this.todoListRepository.updateAll(todoList, where);
   }
 
   @get('/todo-lists/{id}', {
@@ -124,9 +131,16 @@ export class TodoListController {
   })
   async updateById(
     @param.path.number('id') id: number,
-    @requestBody() obj: TodoList,
+    @requestBody({
+      content: {
+        'application/json': {
+          schema: getModelSchemaRef(TodoList, {partial: true}),
+        },
+      },
+    })
+    todoList: Partial<TodoList>,
   ): Promise<void> {
-    await this.todoListRepository.updateById(id, obj);
+    await this.todoListRepository.updateById(id, todoList);
   }
 
   @del('/todo-lists/{id}', {
diff --git a/examples/todo-list/src/controllers/todo.controller.ts b/examples/todo-list/src/controllers/todo.controller.ts
index 1fc5934d2bf2..67d953a64158 100644
--- a/examples/todo-list/src/controllers/todo.controller.ts
+++ b/examples/todo-list/src/controllers/todo.controller.ts
@@ -98,7 +98,14 @@ export class TodoController {
   })
   async updateTodo(
     @param.path.number('id') id: number,
-    @requestBody() todo: Todo,
+    @requestBody({
+      content: {
+        'application/json': {
+          schema: getModelSchemaRef(Todo, {partial: true}),
+        },
+      },
+    })
+    todo: Partial<Todo>,
   ): Promise<void> {
     await this.todoRepo.updateById(id, todo);
   }
diff --git a/examples/todo/src/__tests__/acceptance/todo.acceptance.ts b/examples/todo/src/__tests__/acceptance/todo.acceptance.ts
index e072ce724731..81db0a28c8bb 100644
--- a/examples/todo/src/__tests__/acceptance/todo.acceptance.ts
+++ b/examples/todo/src/__tests__/acceptance/todo.acceptance.ts
@@ -126,7 +126,6 @@ describe('TodoApplication', () => {
 
     it('updates the todo by ID ', async () => {
       const updatedTodo = givenTodo({
-        title: 'DO SOMETHING AWESOME',
         isComplete: true,
       });
       await client
diff --git a/examples/todo/src/controllers/todo.controller.ts b/examples/todo/src/controllers/todo.controller.ts
index 2ae2b6ae5a50..c5697e8c7803 100644
--- a/examples/todo/src/controllers/todo.controller.ts
+++ b/examples/todo/src/controllers/todo.controller.ts
@@ -9,6 +9,7 @@ import {
   del,
   get,
   getFilterSchemaFor,
+  getModelSchemaRef,
   param,
   patch,
   post,
@@ -103,7 +104,14 @@ export class TodoController {
   })
   async updateTodo(
     @param.path.number('id') id: number,
-    @requestBody() todo: Todo,
+    @requestBody({
+      content: {
+        'application/json': {
+          schema: getModelSchemaRef(Todo, {partial: true}),
+        },
+      },
+    })
+    todo: Partial<Todo>,
   ): Promise<void> {
     await this.todoRepo.updateById(id, todo);
   }
diff --git a/packages/cli/generators/controller/templates/src/controllers/controller-rest-template.ts.ejs b/packages/cli/generators/controller/templates/src/controllers/controller-rest-template.ts.ejs
index cf49640903bd..686dd4082ac8 100644
--- a/packages/cli/generators/controller/templates/src/controllers/controller-rest-template.ts.ejs
+++ b/packages/cli/generators/controller/templates/src/controllers/controller-rest-template.ts.ejs
@@ -10,6 +10,7 @@ import {
   param,
   get,
   getFilterSchemaFor,
+  getModelSchemaRef,
   getWhereSchemaFor,
   patch,
   put,
@@ -78,7 +79,14 @@ export class <%= className %>Controller {
     },
   })
   async updateAll(
-    @requestBody() <%= modelVariableName %>: <%= modelName %>,
+    @requestBody({
+      content: {
+        'application/json': {
+          schema: getModelSchemaRef(<%= modelName %>, {partial: true}),
+        },
+      },
+    })
+    <%= modelVariableName %>: <%= modelName %>,
     @param.query.object('where', getWhereSchemaFor(<%= modelName %>)) where?: Where<<%= modelName %>>,
   ): Promise<Count> {
     return await this.<%= repositoryNameCamel %>.updateAll(<%= modelVariableName %>, where);
@@ -105,7 +113,14 @@ export class <%= className %>Controller {
   })
   async updateById(
     @param.path.<%= idType %>('id') id: <%= idType %>,
-    @requestBody() <%= modelVariableName %>: <%= modelName %>,
+    @requestBody({
+      content: {
+        'application/json': {
+          schema: getModelSchemaRef(<%= modelName %>, {partial: true}),
+        },
+      },
+    })
+    <%= modelVariableName %>: <%= modelName %>,
   ): Promise<void> {
     await this.<%= repositoryNameCamel %>.updateById(id, <%= modelVariableName %>);
   }
diff --git a/packages/cli/generators/relation/templates/controller-relation-template-has-many.ts.ejs b/packages/cli/generators/relation/templates/controller-relation-template-has-many.ts.ejs
index 8aaf5f732b3f..0270d7e8584b 100644
--- a/packages/cli/generators/relation/templates/controller-relation-template-has-many.ts.ejs
+++ b/packages/cli/generators/relation/templates/controller-relation-template-has-many.ts.ejs
@@ -8,6 +8,7 @@ import {
 import {
   del,
   get,
+  getModelSchemaRef,
   getWhereSchemaFor,
   param,
   patch,
@@ -69,7 +70,14 @@ export class <%= controllerClassName %> {
   })
   async patch(
     @param.path.<%= sourceModelPrimaryKeyType %>('id') id: <%= sourceModelPrimaryKeyType %>,
-    @requestBody() <%= targetModelRequestBody %>: Partial<<%= targetModelClassName %>>,
+    @requestBody({
+      content: {
+        'application/json': {
+          schema: getModelSchemaRef(<%= targetModelClassName %>, {partial: true}),
+        },
+      },
+    })
+    <%= targetModelRequestBody %>: Partial<<%= targetModelClassName %>>,
     @param.query.object('where', getWhereSchemaFor(<%= targetModelClassName %>)) where?: Where<<%= targetModelClassName %>>,
   ): Promise<Count> {
     return await this.<%= paramSourceRepository %>.<%= relationPropertyName %>(id).patch(<%= targetModelRequestBody %>, where);
diff --git a/packages/cli/test/integration/generators/controller.integration.js b/packages/cli/test/integration/generators/controller.integration.js
index 0803c67d009b..f3160979a182 100644
--- a/packages/cli/test/integration/generators/controller.integration.js
+++ b/packages/cli/test/integration/generators/controller.integration.js
@@ -287,7 +287,7 @@ function checkRestCrudContents() {
     /'200': {/,
     /description: 'ProductReview PATCH success count'/,
     /content: {'application\/json': {schema: CountSchema}},\s{1,}},\s{1,}},\s{1,}}\)/,
-    /async updateAll\(\s{1,}\@requestBody\(\) productReview: ProductReview,\s{1,} @param\.query\.object\('where', getWhereSchemaFor\(ProductReview\)\) where\?: Where<ProductReview>(|,\s+)\)/,
+    /async updateAll\(\s+\@requestBody\({\s+content: {\s+'application\/json': {\s+schema: getModelSchemaRef\(ProductReview, {partial: true}\),\s+},\s+},\s+}\)\s+productReview: ProductReview,\s{1,} @param\.query\.object\('where', getWhereSchemaFor\(ProductReview\)\) where\?: Where<ProductReview>(|,\s+)\)/,
   ];
   patchUpdateAllRegEx.forEach(regex => {
     assert.fileContent(expectedFile, regex);
@@ -312,7 +312,7 @@ function checkRestCrudContents() {
     /responses: {/,
     /'204': {/,
     /description: 'ProductReview PATCH success'/,
-    /async updateById\(\s{1,}\@param.path.number\('id'\) id: number,\s{1,}\@requestBody\(\) productReview: ProductReview,\s+\)/,
+    /async updateById\(\s+\@param.path.number\('id'\) id: number,\s+\@requestBody\({\s+content: {\s+'application\/json': {\s+schema: getModelSchemaRef\(ProductReview, {partial: true}\),\s+},\s+},\s+}\)\s+productReview: ProductReview,\s+\)/,
   ];
   patchUpdateByIdRegEx.forEach(regex => {
     assert.fileContent(expectedFile, regex);
diff --git a/packages/cli/test/integration/generators/hasmany.relation.integration.js b/packages/cli/test/integration/generators/hasmany.relation.integration.js
index 2c6e596c9896..59468136845c 100644
--- a/packages/cli/test/integration/generators/hasmany.relation.integration.js
+++ b/packages/cli/test/integration/generators/hasmany.relation.integration.js
@@ -494,7 +494,8 @@ context('check if the controller file created ', () => {
           /description: 'Customer.Order PATCH success count',\n/,
           /content: { 'application\/json': { schema: CountSchema } },\n/,
           /},\n {4}},\n {2}}\)\n {2}async patch\(\n/,
-          /\@param\.path\.number\('id'\) id: number,\n {4}\@requestBody\(\) order: Partial<Order>,\n/,
+          /\@param\.path\.number\('id'\) id: number,\n {4}/,
+          /\@requestBody\({\s+content: {\s+'application\/json': {\s+schema: getModelSchemaRef\(Order, {partial: true}\),\s+},\s+},\s+}\)\s+order: Partial<Order>,\n/,
           /\@param\.query\.object\('where', getWhereSchemaFor\(Order\)\) where\?: Where<Order>,\n/,
           /\): Promise<Count> {\n/,
           /return await this\.customerRepository\.orders\(id\).patch\(order, where\);\n {2}}\n/,
@@ -505,7 +506,8 @@ context('check if the controller file created ', () => {
           /description: 'CustomerClass.OrderClass PATCH success count',\n/,
           /content: { 'application\/json': { schema: CountSchema } },\n/,
           /},\n {4}},\n {2}}\)\n {2}async patch\(\n/,
-          /\@param\.path\.number\('id'\) id: number,\n {4}\@requestBody\(\) orderClass: Partial<OrderClass>,\n/,
+          /\@param\.path\.number\('id'\) id: number,\n {4}/,
+          /\@requestBody\({\s+content: {\s+'application\/json': {\s+schema: getModelSchemaRef\(OrderClass, {partial: true}\),\s+},\s+},\s+}\)\s+orderClass: Partial<OrderClass>,\n/,
           /\@param\.query\.object\('where', getWhereSchemaFor\(OrderClass\)\) where\?: Where<OrderClass>,\n/,
           /\): Promise<Count> {\n/,
           /return await this\.customerClassRepository\.orderClasses\(id\)\.patch\(orderClass, where\);\n {2}}\n/,
@@ -516,7 +518,8 @@ context('check if the controller file created ', () => {
           /description: 'CustomerClassType.OrderClassType PATCH success count',\n/,
           /content: { 'application\/json': { schema: CountSchema } },\n/,
           /},\n {4}},\n {2}}\)\n {2}async patch\(\n/,
-          /\@param\.path\.number\('id'\) id: number,\n {4}\@requestBody\(\) orderClassType: Partial<OrderClassType>,\n/,
+          /\@param\.path\.number\('id'\) id: number,\n {4}/,
+          /\@requestBody\({\s+content: {\s+'application\/json': {\s+schema: getModelSchemaRef\(OrderClassType, {partial: true}\),\s+},\s+},\s+}\)\s+orderClassType: Partial<OrderClassType>,\n/,
           /\@param\.query\.object\('where', getWhereSchemaFor\(OrderClassType\)\) where\?: Where<OrderClassType>,\n/,
           /\): Promise<Count> {\n/,
           /return await this\.customerClassTypeRepository\.orderClassTypes\(id\).patch\(orderClassType, where\);\n {2}}\n/,
diff --git a/packages/repository-json-schema/src/__tests__/integration/build-schema.integration.ts b/packages/repository-json-schema/src/__tests__/integration/build-schema.integration.ts
index bd87242e0620..67ed2a27c95c 100644
--- a/packages/repository-json-schema/src/__tests__/integration/build-schema.integration.ts
+++ b/packages/repository-json-schema/src/__tests__/integration/build-schema.integration.ts
@@ -910,5 +910,27 @@ describe('build-schema', () => {
         title: 'Category',
       });
     });
+
+    it('emits all properties as optional when the option "partial" is set', () => {
+      @model()
+      class Product extends Entity {
+        @property({id: true, required: true})
+        id: number;
+
+        @property({required: true})
+        name: string;
+
+        @property()
+        optionalDescription: string;
+      }
+
+      const originalSchema = getJsonSchema(Product);
+      expect(originalSchema.required).to.deepEqual(['id', 'name']);
+      expect(originalSchema.title).to.equal('Product');
+
+      const partialSchema = getJsonSchema(Product, {partial: true});
+      expect(partialSchema.required).to.equal(undefined);
+      expect(partialSchema.title).to.equal('ProductPartial');
+    });
   });
 });
diff --git a/packages/repository-json-schema/src/__tests__/unit/build-schema.unit.ts b/packages/repository-json-schema/src/__tests__/unit/build-schema.unit.ts
index af20e0808acd..aa60cf575452 100644
--- a/packages/repository-json-schema/src/__tests__/unit/build-schema.unit.ts
+++ b/packages/repository-json-schema/src/__tests__/unit/build-schema.unit.ts
@@ -10,6 +10,7 @@ import {
 } from '@loopback/repository';
 import {expect} from '@loopback/testlab';
 import {
+  buildModelCacheKey,
   getNavigationalPropertyForRelation,
   metaToJsonProperty,
   stringTypeToWrapper,
@@ -214,4 +215,30 @@ describe('build-schema', () => {
       ).to.throw(/targetsMany attribute missing for Test/);
     });
   });
+
+  describe('buildModelCacheKey', () => {
+    it('returns "modelOnly" when no options were provided', () => {
+      const key = buildModelCacheKey();
+      expect(key).to.equal('modelOnly');
+    });
+
+    it('returns "modelWithRelations" when a single option "includeRelations" is set', () => {
+      const key = buildModelCacheKey({includeRelations: true});
+      expect(key).to.equal('modelWithRelations');
+    });
+
+    it('returns "partial" when a single option "partial" is set', () => {
+      const key = buildModelCacheKey({partial: true});
+      expect(key).to.equal('partial');
+    });
+
+    it('returns concatenated option names otherwise', () => {
+      const key = buildModelCacheKey({
+        // important: object keys are defined in reverse order
+        partial: true,
+        includeRelations: true,
+      });
+      expect(key).to.equal('includeRelations+partial');
+    });
+  });
 });
diff --git a/packages/repository-json-schema/src/build-schema.ts b/packages/repository-json-schema/src/build-schema.ts
index d72fe9aae3cc..10b08d166a22 100644
--- a/packages/repository-json-schema/src/build-schema.ts
+++ b/packages/repository-json-schema/src/build-schema.ts
@@ -16,10 +16,44 @@ import {JSONSchema6 as JSONSchema} from 'json-schema';
 import {JSON_SCHEMA_KEY, MODEL_TYPE_KEYS} from './keys';
 
 export interface JsonSchemaOptions {
+  /**
+   * Set this flag if you want the schema to define navigational properties
+   * for model relations.
+   */
   includeRelations?: boolean;
+
+  /**
+   * Set this flag to mark all model properties as optional. This is typically
+   * used to describe request body of PATCH endpoints.
+   */
+  partial?: boolean;
+
+  /**
+   * @private
+   */
   visited?: {[key: string]: JSONSchema};
 }
 
+/**
+ * @private
+ */
+export function buildModelCacheKey(options: JsonSchemaOptions = {}): string {
+  const flags = Object.keys(options);
+
+  // Backwards compatibility
+  // Preserve cache keys "modelOnly" and "modelWithRelations"
+  if (flags.length === 0) {
+    return MODEL_TYPE_KEYS.ModelOnly;
+  } else if (flags.length === 1 && options.includeRelations) {
+    return MODEL_TYPE_KEYS.ModelWithRelations;
+  }
+
+  // New key schema: concatenate names of options (flags) that are set.
+  // For example: "includeRelations+partial"
+  flags.sort();
+  return flags.join('+');
+}
+
 /**
  * Gets the JSON Schema of a TypeScript model/class by seeing if one exists
  * in a cache. If not, one is generated and then cached.
@@ -32,10 +66,7 @@ export function getJsonSchema(
   // In the near future the metadata will be an object with
   // different titles as keys
   const cached = MetadataInspector.getClassMetadata(JSON_SCHEMA_KEY, ctor);
-  const key =
-    options && options.includeRelations
-      ? MODEL_TYPE_KEYS.ModelWithRelations
-      : MODEL_TYPE_KEYS.ModelOnly;
+  const key = buildModelCacheKey(options);
   let schema = cached && cached[key];
 
   if (!schema) {
@@ -252,6 +283,9 @@ export function modelToJsonSchema(
   }
 
   let title = meta.title || ctor.name;
+  if (options.partial) {
+    title += 'Partial';
+  }
   if (options.includeRelations) {
     title += 'WithRelations';
   }
@@ -279,7 +313,7 @@ export function modelToJsonSchema(
     result.properties[p] = metaToJsonProperty(metaProperty);
 
     // handling 'required' metadata
-    if (metaProperty.required) {
+    if (metaProperty.required && !options.partial) {
       result.required = result.required || [];
       result.required.push(p);
     }
diff --git a/packages/repository-json-schema/src/keys.ts b/packages/repository-json-schema/src/keys.ts
index dd1df19add29..90ba45fd96e1 100644
--- a/packages/repository-json-schema/src/keys.ts
+++ b/packages/repository-json-schema/src/keys.ts
@@ -6,6 +6,11 @@
 import {MetadataAccessor} from '@loopback/metadata';
 import {JSONSchema6 as JSONSchema} from 'json-schema';
 
+/**
+ * TODO(semver-major) remove these constants in the next major version
+ * @deprecated Use the helper `buildModelCacheKey` to obtain the cache key
+ * for a given set of schema options.
+ */
 export const enum MODEL_TYPE_KEYS {
   ModelOnly = 'modelOnly',
   ModelWithRelations = 'modelWithRelations',
@@ -15,6 +20,6 @@ export const enum MODEL_TYPE_KEYS {
  * Metadata key used to set or retrieve repository JSON Schema
  */
 export const JSON_SCHEMA_KEY = MetadataAccessor.create<
-  {[options in MODEL_TYPE_KEYS]: JSONSchema},
+  {[key: string]: JSONSchema},
   ClassDecorator
 >('loopback:json-schema');