diff --git a/src/app/core/common-components/entity-form/entity-form.service.spec.ts b/src/app/core/common-components/entity-form/entity-form.service.spec.ts
index 2f6a0e3b0c..723e2509e5 100644
--- a/src/app/core/common-components/entity-form/entity-form.service.spec.ts
+++ b/src/app/core/common-components/entity-form/entity-form.service.spec.ts
@@ -29,6 +29,8 @@ import { User } from "../../user/user";
 import { TEST_USER } from "../../user/demo-user-generator.service";
 import { CurrentUserSubject } from "../../session/current-user-subject";
 import moment from "moment";
+import { EntityMapperService } from "../../entity/entity-mapper/entity-mapper.service";
+import { MockEntityMapperService } from "../../entity/entity-mapper/mock-entity-mapper-service";
 
 describe("EntityFormService", () => {
   let service: EntityFormService;
@@ -306,6 +308,25 @@ describe("EntityFormService", () => {
     Entity.schema.delete("test");
   });
 
+  it("should not save 'null' as value from empty form fields", async () => {
+    Entity.schema.set("test", { dataType: "string" });
+
+    const entity = new Entity();
+    const form = service.createFormGroup([{ id: "test" }], entity);
+    form.get("test").reset();
+    expect(form.get("test").getRawValue()).toEqual(null);
+
+    await service.saveChanges(form, entity);
+
+    const entityMapper = TestBed.inject(
+      EntityMapperService,
+    ) as MockEntityMapperService;
+    const actualSaved = entityMapper.get(entity.getType(), entity.getId());
+    expect(actualSaved).toEqual(entity);
+    // service should remove 'null' value, which are the default for empty form fields
+    expect(actualSaved["test"]).not.toEqual(null);
+  });
+
   it("should add column definitions from property schema", () => {
     class Test extends Child {
       @DatabaseField({
diff --git a/src/app/core/common-components/entity-form/entity-form.service.ts b/src/app/core/common-components/entity-form/entity-form.service.ts
index 9946d53330..779ccc4d29 100644
--- a/src/app/core/common-components/entity-form/entity-form.service.ts
+++ b/src/app/core/common-components/entity-form/entity-form.service.ts
@@ -237,10 +237,15 @@ export class EntityFormService {
     entity: T,
   ): Promise<T> {
     this.checkFormValidity(form);
+
     const updatedEntity = entity.copy() as T;
-    Object.assign(updatedEntity, form.getRawValue());
-    updatedEntity.assertValid();
+    for (const [key, value] of Object.entries(form.getRawValue())) {
+      if (value !== null) {
+        updatedEntity[key] = value;
+      }
+    }
 
+    updatedEntity.assertValid();
     this.assertPermissionsToSave(entity, updatedEntity);
 
     return this.entityMapper
diff --git a/src/app/core/entity/entity-actions/entity-anonymize.service.spec.ts b/src/app/core/entity/entity-actions/entity-anonymize.service.spec.ts
index 1befc74733..ee109b7203 100644
--- a/src/app/core/entity/entity-actions/entity-anonymize.service.spec.ts
+++ b/src/app/core/entity/entity-actions/entity-anonymize.service.spec.ts
@@ -98,7 +98,7 @@ describe("EntityAnonymizeService", () => {
     }
   }
 
-  it("should anonymize and only keep properties marked to be retained", async () => {
+  it("should anonymize and only keep properties marked to be retained, setting others to 'null'", async () => {
     const entity = new AnonymizableEntity();
     entity.defaultField = "test";
     entity.retainedField = "test";
@@ -107,13 +107,12 @@ describe("EntityAnonymizeService", () => {
 
     AnonymizableEntity.expectAnonymized(
       entity.getId(),
-      AnonymizableEntity.create({ retainedField: "test" }),
+      AnonymizableEntity.create({ retainedField: "test", defaultField: null }),
     );
   });
 
   it("should anonymize and keep empty record without any fields", async () => {
     const entity = new AnonymizableEntity();
-    entity.defaultField = "test";
 
     await service.anonymizeEntity(entity);
 
@@ -140,6 +139,7 @@ describe("EntityAnonymizeService", () => {
       AnonymizableEntity.create({
         inactive: true,
         anonymized: true,
+        defaultField: null,
         ...entityProperties,
       }),
       true,
@@ -154,7 +154,11 @@ describe("EntityAnonymizeService", () => {
 
     AnonymizableEntity.expectAnonymized(
       entity.getId(),
-      AnonymizableEntity.create({ inactive: true, anonymized: true }),
+      AnonymizableEntity.create({
+        inactive: true,
+        anonymized: true,
+        defaultField: null,
+      }),
       true,
     );
   });
@@ -187,7 +191,7 @@ describe("EntityAnonymizeService", () => {
 
     AnonymizableEntity.expectAnonymized(
       entity.getId(),
-      AnonymizableEntity.create({}),
+      AnonymizableEntity.create({ file: null }),
     );
     expect(mockFileService.removeFile).toHaveBeenCalled();
   });
@@ -234,6 +238,12 @@ describe("EntityAnonymizeService", () => {
       expectedAnonymizedEntity.inactive = true;
       expectedAnonymizedEntity.anonymized = true;
 
+      for (const [k, v] of Object.entries(actualEntity)) {
+        if (v === null) {
+          expectedAnonymizedEntity[k] = null;
+        }
+      }
+
       expect(comparableEntityData(actualEntity)).toEqual(
         comparableEntityData(expectedAnonymizedEntity),
       );
diff --git a/src/app/core/entity/entity-actions/entity-anonymize.service.ts b/src/app/core/entity/entity-actions/entity-anonymize.service.ts
index 731e5757e6..252f20cf21 100644
--- a/src/app/core/entity/entity-actions/entity-anonymize.service.ts
+++ b/src/app/core/entity/entity-actions/entity-anonymize.service.ts
@@ -92,7 +92,9 @@ export class EntityAnonymizeService extends CascadingEntityAction {
       await firstValueFrom(this.fileService.removeFile(entity, key));
     }
 
-    delete entity[key];
+    if (entity[key] !== undefined) {
+      entity[key] = null;
+    }
   }
 
   private async keepEntityUnchanged(e: Entity): Promise<CascadingActionResult> {
diff --git a/src/app/core/entity/schema/entity-schema.service.spec.ts b/src/app/core/entity/schema/entity-schema.service.spec.ts
index bd5f59455d..3868265e62 100644
--- a/src/app/core/entity/schema/entity-schema.service.spec.ts
+++ b/src/app/core/entity/schema/entity-schema.service.spec.ts
@@ -58,6 +58,25 @@ describe("EntitySchemaService", () => {
     expect(rawData.aString).toEqual("192");
   });
 
+  it("should keep 'null' as value if explicitly set", () => {
+    class TestEntity extends Entity {
+      @DatabaseField() aString: string;
+    }
+
+    const entity = new TestEntity();
+
+    const data = {
+      _id: entity.getId(),
+      aString: null,
+    };
+    service.loadDataIntoEntity(entity, data);
+
+    expect(entity.aString).toEqual(null);
+
+    const rawData = service.transformEntityToDatabaseFormat(entity);
+    expect(rawData.aString).toEqual(null);
+  });
+
   it("should return the directly defined component name for viewing and editing a property", () => {
     class Test extends Entity {
       @DatabaseField({
diff --git a/src/app/core/entity/schema/entity-schema.service.ts b/src/app/core/entity/schema/entity-schema.service.ts
index 4fe5075420..4a5ad4a7e8 100644
--- a/src/app/core/entity/schema/entity-schema.service.ts
+++ b/src/app/core/entity/schema/entity-schema.service.ts
@@ -104,7 +104,7 @@ export class EntitySchemaService {
     for (const key of schema.keys()) {
       const schemaField: EntitySchemaField = schema.get(key);
 
-      if (data[key] === undefined || data[key] === null) {
+      if (data[key] === undefined) {
         continue;
       }
 
@@ -153,7 +153,7 @@ export class EntitySchemaService {
       let value = entity[key];
       const schemaField: EntitySchemaField = schema.get(key);
 
-      if (value === undefined || value === null) {
+      if (value === undefined) {
         // skip and keep undefined
         continue;
       }
@@ -218,6 +218,11 @@ export class EntitySchemaService {
     schemaField: EntitySchemaField,
     entity?: Entity,
   ) {
+    if (value === null) {
+      // keep 'null' to be able to explicitly mark a value as being reset
+      return null;
+    }
+
     return this.getDatatypeOrDefault(
       schemaField.dataType,
     ).transformToDatabaseFormat(value, schemaField, entity);
@@ -234,6 +239,11 @@ export class EntitySchemaService {
     schemaField: EntitySchemaField,
     dataObject?: any,
   ) {
+    if (value === null) {
+      // keep 'null' to be able to explicitly mark a value as being reset
+      return null;
+    }
+
     return this.getDatatypeOrDefault(
       schemaField.dataType,
     ).transformToObjectFormat(value, schemaField, dataObject);