diff --git a/packages/types/src/documents/app/table/schema.ts b/packages/types/src/documents/app/table/schema.ts
index 3a74134ddd..45e39268ac 100644
--- a/packages/types/src/documents/app/table/schema.ts
+++ b/packages/types/src/documents/app/table/schema.ts
@@ -17,14 +17,13 @@ export interface UIFieldMetadata {
 }
 
 interface BaseRelationshipFieldMetadata
-  extends BaseFieldSchema<
-    AutoFieldSubType.CREATED_BY | AutoFieldSubType.UPDATED_BY | undefined
-  > {
+  extends Omit<BaseFieldSchema, "subtype"> {
   type: FieldType.LINK
   main?: boolean
   fieldName: string
   tableId: string
   tableRev?: string
+  subtype?: AutoFieldSubType.CREATED_BY | AutoFieldSubType.UPDATED_BY
 }
 
 // External tables use junction tables, internal tables don't require them
@@ -61,17 +60,18 @@ export type RelationshipFieldMetadata =
   | ManyToOneRelationshipFieldMetadata
 
 export interface AutoColumnFieldMetadata
-  extends BaseFieldSchema<AutoFieldSubType | undefined> {
+  extends Omit<BaseFieldSchema, "subtype"> {
   type: FieldType.AUTO
   autocolumn: true
+  subtype?: AutoFieldSubType
   lastID?: number
   // if the column was turned to an auto-column for SQL, explains why (primary, foreign etc)
   autoReason?: AutoReason
 }
 
-export interface NumberFieldMetadata
-  extends BaseFieldSchema<AutoFieldSubType.AUTO_ID | undefined> {
+export interface NumberFieldMetadata extends Omit<BaseFieldSchema, "subtype"> {
   type: FieldType.NUMBER
+  subtype?: AutoFieldSubType.AUTO_ID
   lastID?: number
   autoReason?: AutoReason.FOREIGN_KEY
   // used specifically when Budibase generates external tables, this denotes if a number field
@@ -82,18 +82,16 @@ export interface NumberFieldMetadata
   }
 }
 
-export interface JsonFieldMetadata
-  extends BaseFieldSchema<JsonFieldSubType.ARRAY | undefined> {
+export interface JsonFieldMetadata extends Omit<BaseFieldSchema, "subtype"> {
   type: FieldType.JSON
+  subtype?: JsonFieldSubType.ARRAY
 }
 
-export interface DateFieldMetadata
-  extends BaseFieldSchema<
-    AutoFieldSubType.CREATED_AT | AutoFieldSubType.UPDATED_AT | undefined
-  > {
+export interface DateFieldMetadata extends Omit<BaseFieldSchema, "subtype"> {
   type: FieldType.DATETIME
   ignoreTimezones?: boolean
   timeOnly?: boolean
+  subtype?: AutoFieldSubType.CREATED_AT | AutoFieldSubType.UPDATED_AT
 }
 
 export interface LongFormFieldMetadata extends BaseFieldSchema {
@@ -108,15 +106,16 @@ export interface FormulaFieldMetadata extends BaseFieldSchema {
 }
 
 export interface BBReferenceFieldMetadata
-  extends BaseFieldSchema<FieldSubtype.USER | FieldSubtype.USERS> {
+  extends Omit<BaseFieldSchema, "subtype"> {
   type: FieldType.BB_REFERENCE
-
+  subtype: FieldSubtype.USER | FieldSubtype.USERS
   relationshipType?: RelationshipType
 }
 
 export interface AttachmentFieldMetadata
-  extends BaseFieldSchema<FieldSubtype.SINGLE | undefined> {
+  extends Omit<BaseFieldSchema, "subtype"> {
   type: FieldType.ATTACHMENT
+  subtype?: FieldSubtype.SINGLE
 }
 
 export interface FieldConstraints {
@@ -143,7 +142,7 @@ export interface FieldConstraints {
   }
 }
 
-interface BaseFieldSchema<TSubtype = never> extends UIFieldMetadata {
+interface BaseFieldSchema extends UIFieldMetadata {
   type: FieldType
   name: string
   sortable?: boolean
@@ -152,7 +151,7 @@ interface BaseFieldSchema<TSubtype = never> extends UIFieldMetadata {
   constraints?: FieldConstraints
   autocolumn?: boolean
   autoReason?: AutoReason.FOREIGN_KEY
-  subtype: TSubtype
+  subtype?: never
 }
 
 interface OtherFieldMetadata extends BaseFieldSchema {
@@ -164,6 +163,7 @@ interface OtherFieldMetadata extends BaseFieldSchema {
     | FieldType.FORMULA
     | FieldType.NUMBER
     | FieldType.LONGFORM
+    | FieldType.BB_REFERENCE
     | FieldType.ATTACHMENT
   >
 }
@@ -176,9 +176,9 @@ export type FieldSchema =
   | FormulaFieldMetadata
   | NumberFieldMetadata
   | LongFormFieldMetadata
-  | AttachmentFieldMetadata
   | BBReferenceFieldMetadata
   | JsonFieldMetadata
+  | AttachmentFieldMetadata
 
 export interface TableSchema {
   [key: string]: FieldSchema
@@ -213,3 +213,9 @@ export function isBBReferenceField(
 ): field is BBReferenceFieldMetadata {
   return field.type === FieldType.BB_REFERENCE
 }
+
+export function isAttachmentField(
+  field: FieldSchema
+): field is AttachmentFieldMetadata {
+  return field.type === FieldType.ATTACHMENT
+}