diff --git a/packages/core/database/src/__tests__/fields/string-field.test.ts b/packages/core/database/src/__tests__/fields/string-field.test.ts
index 88898d7553..26b822f65d 100644
--- a/packages/core/database/src/__tests__/fields/string-field.test.ts
+++ b/packages/core/database/src/__tests__/fields/string-field.test.ts
@@ -115,9 +115,7 @@ describe('string field', () => {
     const model = await collection.model.create({
       name: '  n1\n ',
     });
-    expect(model.toJSON()).toMatchObject({
-      name: 'n1',
-    });
+    expect(model.get('name')).toBe('n1');
   });
 
   it('trim when value is null should be null', async () => {
@@ -129,9 +127,7 @@ describe('string field', () => {
     const model = await collection.model.create({
       name: null,
     });
-    expect(model.toJSON()).toMatchObject({
-      name: null,
-    });
+    expect(model.get('name')).toBeFalsy();
   });
 
   it('when value is number should be convert to string', async () => {
@@ -143,8 +139,6 @@ describe('string field', () => {
     const model = await collection.model.create({
       name: 123,
     });
-    expect(model.toJSON()).toMatchObject({
-      name: '123',
-    });
+    expect(model.get('name')).toBe('123');
   });
 });
diff --git a/packages/core/database/src/__tests__/fields/text-field.test.ts b/packages/core/database/src/__tests__/fields/text-field.test.ts
index 1225367b9b..d79e181960 100644
--- a/packages/core/database/src/__tests__/fields/text-field.test.ts
+++ b/packages/core/database/src/__tests__/fields/text-field.test.ts
@@ -62,9 +62,7 @@ describe('text field', () => {
     const model = await collection.model.create({
       name: '  n1\n ',
     });
-    expect(model.toJSON()).toMatchObject({
-      name: 'n1',
-    });
+    expect(model.get('name')).toBe('n1');
   });
 
   it('trim when value is null should be null', async () => {
@@ -76,9 +74,7 @@ describe('text field', () => {
     const model = await collection.model.create({
       name: null,
     });
-    expect(model.toJSON()).toMatchObject({
-      name: null,
-    });
+    expect(model.get('name')).toBeFalsy();
   });
 
   it('when value is number should be convert to string', async () => {
@@ -90,8 +86,6 @@ describe('text field', () => {
     const model = await collection.model.create({
       name: 123,
     });
-    expect(model.toJSON()).toMatchObject({
-      name: '123',
-    });
+    expect(model.get('name')).toBe('123');
   });
 });
diff --git a/packages/core/database/src/fields/string-field.ts b/packages/core/database/src/fields/string-field.ts
index 1b0719af8f..653beddf66 100644
--- a/packages/core/database/src/fields/string-field.ts
+++ b/packages/core/database/src/fields/string-field.ts
@@ -20,12 +20,16 @@ export class StringField extends Field {
   }
 
   additionalSequelizeOptions() {
-    const { name, trim } = this.options;
+    const { name, trim, unique } = this.options;
 
     return {
       set(value) {
+        if (unique && value === '') {
+          value = null;
+        }
         if (value == null) {
-          return value;
+          this.setDataValue(name, null);
+          return;
         }
         if (typeof value !== 'string') {
           value = value.toString();
diff --git a/packages/core/database/src/fields/text-field.ts b/packages/core/database/src/fields/text-field.ts
index 4b045db75e..10b7d99811 100644
--- a/packages/core/database/src/fields/text-field.ts
+++ b/packages/core/database/src/fields/text-field.ts
@@ -25,12 +25,16 @@ export class TextField extends Field {
   }
 
   additionalSequelizeOptions() {
-    const { name, trim } = this.options;
+    const { name, trim, unique } = this.options;
 
     return {
       set(value) {
+        if (unique && value === '') {
+          value = null;
+        }
         if (value == null) {
-          return value;
+          this.setDataValue(name, null);
+          return;
         }
         if (typeof value !== 'string') {
           value = value.toString();