diff --git a/packages/bindx/src/handles/EntityHandle.ts b/packages/bindx/src/handles/EntityHandle.ts
index d5db13a..27f653e 100644
--- a/packages/bindx/src/handles/EntityHandle.ts
+++ b/packages/bindx/src/handles/EntityHandle.ts
@@ -490,8 +490,12 @@ export class EntityHandle<T extends object = object, TSelected = T> extends Enti
 				}
 
 				if (fieldDef.type === 'hasOne') {
-					// Has-one relation - return HasOneHandle
-					return this.hasOne(fieldName, nestedSelection)
+					// Has-one relation - return HasOneHandle or null for nullable disconnected
+					const handle = this.hasOne(fieldName, nestedSelection)
+					if (fieldDef.nullable && handle.$state === 'disconnected') {
+						return null
+					}
+					return handle
 				}
 
 				if (fieldDef.type === 'hasMany') {
diff --git a/packages/bindx/src/handles/HasOneHandle.ts b/packages/bindx/src/handles/HasOneHandle.ts
index 2afbce6..b678590 100644
--- a/packages/bindx/src/handles/HasOneHandle.ts
+++ b/packages/bindx/src/handles/HasOneHandle.ts
@@ -202,6 +202,19 @@ export class HasOneHandle<TEntity extends object = object, TSelected = TEntity>
 		return this.entity.$fields
 	}
 
+	/**
+	 * Gets a has-one handle for a nested relation on the related entity.
+	 * Delegates to the underlying EntityHandle.
+	 * Enables entity.author.$hasOne('avatar') pattern.
+	 */
+	hasOne<TRelated extends object>(fieldName: string, nestedSelection?: SelectionMeta): HasOneAccessor<TRelated> {
+		const raw = this.entityRaw
+		if (raw instanceof EntityHandle) {
+			return raw.hasOne<TRelated>(fieldName, nestedSelection)
+		}
+		throw new Error(`Cannot access has-one relation "${fieldName}" on a disconnected placeholder entity`)
+	}
+
 	/**
 	 * Gets the raw (unproxied) related entity handle.
 	 * Returns raw EntityHandle or raw PlaceholderHandle.
diff --git a/packages/bindx/src/handles/types.ts b/packages/bindx/src/handles/types.ts
index 5627632..c1e4687 100644
--- a/packages/bindx/src/handles/types.ts
+++ b/packages/bindx/src/handles/types.ts
@@ -78,6 +78,8 @@ export type HasOneKeys<T> = {
 			: never
 }[keyof T]
 
+type NullableHasOne<T, TAccessor> = null extends T ? TAccessor | null : TAccessor
+
 // ============================================================================
 // Symbols
 // ============================================================================
@@ -341,7 +343,21 @@ export type EntityAccessor<
 > = EntityRef<TEntity, TSelected, TBrand, TEntityName, TSchema, TRoleMap> & {
 	readonly $fields: EntityFieldsAccessor<TEntity, TSelected, TSchema>
 	readonly $data: TSelected | null
-} & EntityFieldsAccessor<TEntity, TSelected, TSchema>
+} & EntityFieldsAccessor<TEntity, TSelected, TSchema> & EntityHasOneMethods<TEntity, TSchema>
+
+/**
+ * Provides $hasOne(fieldName) method that always returns HasOneAccessor (never null).
+ * Used for mutation access (connect/disconnect) on nullable has-one relations.
+ */
+type EntityHasOneMethods<TEntity, TSchema extends Record<string, object>> = {
+	$hasOne<K extends HasOneKeys<TEntity> & keyof TEntity & string>(fieldName: K): HasOneAccessor<
+		NonNullable<TEntity[K]>,
+		NonNullable<TEntity[K]>,
+		AnyBrand,
+		EntityNameFromType<TSchema, NonNullable<TEntity[K]>>,
+		TSchema
+	>
+}
 
 // ============================================================================
 // ENTITY FIELDS MAPPING TYPES
@@ -359,7 +375,7 @@ export type EntityFields<T> = {
 			: never
 		: never
 } & {
-	[K in HasOneKeys<T>]: HasOneAccessor<NonNullable<T[K]>>
+	[K in HasOneKeys<T>]: NullableHasOne<T[K], HasOneAccessor<NonNullable<T[K]>>>
 }
 
 /**
@@ -372,13 +388,13 @@ type FieldRefType<TEntity, TSelected, TSchema extends Record<string, object>, K
 			? HasManyRef<U, ExtractNestedSelection<TSelected, K> extends (infer S)[] ? S : U, AnyBrand, EntityNameFromType<TSchema, U>, TSchema>
 			: never
 		: never) :
-	K extends HasOneKeys<TEntity> ? HasOneRef<
+	K extends HasOneKeys<TEntity> ? NullableHasOne<TEntity[K], HasOneRef<
 		NonNullable<TEntity[K]>,
 		ExtractNestedSelection<TSelected, K> extends object ? ExtractNestedSelection<TSelected, K> : NonNullable<TEntity[K]>,
 		AnyBrand,
 		EntityNameFromType<TSchema, NonNullable<TEntity[K]>>,
 		TSchema
-	> :
+	>> :
 	never
 
 /**
@@ -391,13 +407,13 @@ type FieldAccessorType<TEntity, TSelected, TSchema extends Record<string, object
 			? HasManyAccessor<U, ExtractNestedSelection<TSelected, K> extends (infer S)[] ? S : U, AnyBrand, EntityNameFromType<TSchema, U>, TSchema>
 			: never
 		: never) :
-	K extends HasOneKeys<TEntity> ? HasOneAccessor<
+	K extends HasOneKeys<TEntity> ? NullableHasOne<TEntity[K], HasOneAccessor<
 		NonNullable<TEntity[K]>,
 		ExtractNestedSelection<TSelected, K> extends object ? ExtractNestedSelection<TSelected, K> : NonNullable<TEntity[K]>,
 		AnyBrand,
 		EntityNameFromType<TSchema, NonNullable<TEntity[K]>>,
 		TSchema
-	> :
+	>> :
 	never
 
 /**
diff --git a/tests/react/dataview/createRelationColumn.test.tsx b/tests/react/dataview/createRelationColumn.test.tsx
index 501f452..16ac9af 100644
--- a/tests/react/dataview/createRelationColumn.test.tsx
+++ b/tests/react/dataview/createRelationColumn.test.tsx
@@ -98,7 +98,7 @@ describe('createRelationColumn — hasOne', () => {
 	test('produces leaf with correct metadata', () => {
 		const proxy = createProjectProxy()
 		const jsx = (
-			<HeadlessHasOneColumn field={proxy.organization} header="Org">
+			<HeadlessHasOneColumn field={proxy.organization!} header="Org">
 				{(org: any) => org.name.value}
 			</HeadlessHasOneColumn>
 		)
@@ -120,7 +120,7 @@ describe('createRelationColumn — hasOne', () => {
 	test('filter is enabled by default', () => {
 		const proxy = createProjectProxy()
 		const jsx = (
-			<HeadlessHasOneColumn field={proxy.organization}>
+			<HeadlessHasOneColumn field={proxy.organization!}>
 				{(org: any) => org.name.value}
 			</HeadlessHasOneColumn>
 		)
@@ -132,7 +132,7 @@ describe('createRelationColumn — hasOne', () => {
 	test('filter can be disabled', () => {
 		const proxy = createProjectProxy()
 		const jsx = (
-			<HeadlessHasOneColumn field={proxy.organization} filter={false}>
+			<HeadlessHasOneColumn field={proxy.organization!} filter={false}>
 				{(org: any) => org.name.value}
 			</HeadlessHasOneColumn>
 		)
@@ -144,7 +144,7 @@ describe('createRelationColumn — hasOne', () => {
 	test('headless column has no renderFilter', () => {
 		const proxy = createProjectProxy()
 		const jsx = (
-			<HeadlessHasOneColumn field={proxy.organization}>
+			<HeadlessHasOneColumn field={proxy.organization!}>
 				{(org: any) => org.name.value}
 			</HeadlessHasOneColumn>
 		)
@@ -159,7 +159,7 @@ describe('createRelationColumn — hasOne', () => {
 		})
 		const proxy = createProjectProxy()
 		const jsx = (
-			<StyledHasOneColumn field={proxy.organization}>
+			<StyledHasOneColumn field={proxy.organization!}>
 				{(org: any) => org.name.value}
 			</StyledHasOneColumn>
 		)
@@ -174,7 +174,7 @@ describe('createRelationColumn — hasOne', () => {
 		})
 		const proxy = createProjectProxy()
 		const jsx = (
-			<StyledHasOneColumn field={proxy.organization}>
+			<StyledHasOneColumn field={proxy.organization!}>
 				{(org: any) => org.name.value}
 			</StyledHasOneColumn>
 		)
@@ -190,7 +190,7 @@ describe('createRelationColumn — hasOne', () => {
 		})
 		const proxy = createProjectProxy()
 		const jsx = (
-			<StyledHasOneColumn field={proxy.organization} renderCellWrapper={userWrapper}>
+			<StyledHasOneColumn field={proxy.organization!} renderCellWrapper={userWrapper}>
 				{(org: any) => org.name.value}
 			</StyledHasOneColumn>
 		)
@@ -201,7 +201,7 @@ describe('createRelationColumn — hasOne', () => {
 	test('relatedSelection captures fields from children', () => {
 		const proxy = createProjectProxy()
 		const jsx = (
-			<HeadlessHasOneColumn field={proxy.organization}>
+			<HeadlessHasOneColumn field={proxy.organization!}>
 				{(org: any) => org.name.value}
 			</HeadlessHasOneColumn>
 		)
diff --git a/tests/react/dataview/dataGrid.test.tsx b/tests/react/dataview/dataGrid.test.tsx
index 432ae93..3daa1a1 100644
--- a/tests/react/dataview/dataGrid.test.tsx
+++ b/tests/react/dataview/dataGrid.test.tsx
@@ -177,7 +177,7 @@ describe('DataGrid', () => {
 						{it => (
 							<>
 								<DataGridTextColumn field={it.title} header="Title" />
-								<DataGridHasOneColumn field={it.author} header="Author">
+								<DataGridHasOneColumn field={it.author!} header="Author">
 									{(author: any) => author.name}
 								</DataGridHasOneColumn>
 								<TestTable />
diff --git a/tests/react/dataview/dataGridColumns.test.tsx b/tests/react/dataview/dataGridColumns.test.tsx
index 50abec7..04d1aa1 100644
--- a/tests/react/dataview/dataGridColumns.test.tsx
+++ b/tests/react/dataview/dataGridColumns.test.tsx
@@ -501,7 +501,7 @@ describe('DataGrid layout via DataGridLayout marker', () => {
 									<div>
 										<span data-testid="tile-title"><Field field={item.title} /></span>
 										<span data-testid="tile-author">
-											<HasOne field={item.author}>
+											<HasOne field={item.author!}>
 												{(author: any) => <Field field={author.name} />}
 											</HasOne>
 										</span>
diff --git a/tests/react/dataview/select.test.tsx b/tests/react/dataview/select.test.tsx
index d06819b..9b6f63e 100644
--- a/tests/react/dataview/select.test.tsx
+++ b/tests/react/dataview/select.test.tsx
@@ -137,7 +137,7 @@ describe('Select', () => {
 			}
 
 			return (
-				<Select relation={article.category} options={entities.Category}>
+				<Select relation={article.category!} options={entities.Category}>
 					<div>
 						<SelectPlaceholder>
 							<span data-testid="placeholder">Select category</span>
@@ -180,7 +180,7 @@ describe('Select', () => {
 			}
 
 			return (
-				<Select relation={article.category} options={entities.Category}>
+				<Select relation={article.category!} options={entities.Category}>
 					<div>
 						<SelectPlaceholder>
 							<span data-testid="placeholder">Select category</span>
@@ -221,19 +221,19 @@ describe('Select', () => {
 			}
 
 			return (
-				<Select relation={article.category} options={entities.Category}>
+				<Select relation={article.category!} options={entities.Category}>
 					<div>
-						<span data-testid="state">{article.category.$state}</span>
-						<span data-testid="cat-id">{article.category.$state === 'connected' ? article.category.$id : 'none'}</span>
+						<span data-testid="state">{article.category!.$state}</span>
+						<span data-testid="cat-id">{article.category!.$state === 'connected' ? article.category!.$id : 'none'}</span>
 						<button
 							data-testid="connect-cat-2"
-							onClick={() => article.category.$connect('cat-2')}
+							onClick={() => article.category!.$connect('cat-2')}
 						>
 							Connect
 						</button>
 						<button
 							data-testid="disconnect"
-							onClick={() => article.category.$disconnect()}
+							onClick={() => article.category!.$disconnect()}
 						>
 							Disconnect
 						</button>
@@ -285,7 +285,7 @@ describe('Select', () => {
 			}
 
 			return (
-				<Select relation={article.category} options={entities.Category}>
+				<Select relation={article.category!} options={entities.Category}>
 					<SelectDataView selection={it => <span>{(it as unknown as { name: { value: string } }).name.value}</span>}>
 						<DataViewLoaderState loaded>
 							<DataViewEachRow>
diff --git a/tests/react/hooks/useEntity/relations.test.tsx b/tests/react/hooks/useEntity/relations.test.tsx
index 40b2bd1..09227a2 100644
--- a/tests/react/hooks/useEntity/relations.test.tsx
+++ b/tests/react/hooks/useEntity/relations.test.tsx
@@ -36,8 +36,8 @@ describe('useEntity hook - relation field handles', () => {
 			return (
 				<div>
 					<h1 data-testid="title">{article.title.value}</h1>
-					<p data-testid="author-name-field">{article.author.name.value}</p>
-					<p data-testid="author-email-field">{article.author.email.value}</p>
+					<p data-testid="author-name-field">{article.author!.name.value}</p>
+					<p data-testid="author-email-field">{article.author!.email.value}</p>
 				</div>
 			)
 		}
diff --git a/tests/react/hooks/useEntity/rendering.test.tsx b/tests/react/hooks/useEntity/rendering.test.tsx
index cee1466..eec999b 100644
--- a/tests/react/hooks/useEntity/rendering.test.tsx
+++ b/tests/react/hooks/useEntity/rendering.test.tsx
@@ -253,7 +253,7 @@ describe('useEntity hook - data rendering', () => {
 			return (
 				<div data-testid="editor">
 					<span data-testid="editor-title">{article.title.value}</span>
-					<span data-testid="editor-author">{article.author.name.value}</span>
+					<span data-testid="editor-author">{article.author!.name.value}</span>
 					<span data-testid="editor-location">{article.$data!.location?.label ?? 'N/A'}</span>
 					<span data-testid="editor-tags">{article.$data!.tags?.length ?? 0}</span>
 				</div>
diff --git a/tests/react/jsx/HasOne.test.tsx b/tests/react/jsx/HasOne.test.tsx
index fef11cb..724b087 100644
--- a/tests/react/jsx/HasOne.test.tsx
+++ b/tests/react/jsx/HasOne.test.tsx
@@ -120,7 +120,7 @@ describe('HasOne component', () => {
 
 				return (
 					<div>
-						<HasOne field={article.author}>
+						<HasOne field={article.author!}>
 							{author => <AuthorNameEmail author={author} />}
 						</HasOne>
 					</div>
@@ -160,7 +160,7 @@ describe('HasOne component', () => {
 				// Use $id and $fields.$name.value for proper access
 				return (
 					<div>
-						<span data-testid="author-id">{article.author.$id ?? 'placeholder'}</span>
+						<span data-testid="author-id">{article.author!.$id ?? 'placeholder'}</span>
 						<span data-testid="title">{article.title.value}</span>
 					</div>
 				)
@@ -202,7 +202,7 @@ describe('HasOne component', () => {
 
 				return (
 					<div>
-						<HasOne field={article.author}>
+						<HasOne field={article.author!}>
 							{author => <AuthorInfo author={author} />}
 						</HasOne>
 					</div>
@@ -237,7 +237,7 @@ describe('HasOne component', () => {
 
 				return (
 					<div>
-						<HasOne field={article.author}>
+						<HasOne field={article.author!}>
 							{author => <AuthorNameWithUpdate author={author} testIdName="author-name" testIdBtn="update-btn" newName="Jane Doe" />}
 						</HasOne>
 					</div>
@@ -279,7 +279,7 @@ describe('HasOne component', () => {
 
 				return (
 					<div>
-						<HasOne field={article.author}>
+						<HasOne field={article.author!}>
 							{author => (
 								<div data-testid="author-id">{author.id}</div>
 							)}
@@ -322,7 +322,7 @@ describe('HasOne component', () => {
 
 				return (
 					<div>
-						<HasOne field={article.location}>
+						<HasOne field={article.location!}>
 							{location => <LocationInfo location={location} />}
 						</HasOne>
 					</div>
@@ -363,7 +363,7 @@ describe('HasOne component', () => {
 
 				return (
 					<div>
-						<HasOne field={article.author}>
+						<HasOne field={article.author!}>
 							{author => <AuthorCard author={author} />}
 						</HasOne>
 					</div>
@@ -407,7 +407,7 @@ describe('HasOne component', () => {
 
 				return (
 					<div>
-						<HasOne field={article.author}>
+						<HasOne field={article.author!}>
 							{author => <AuthorNameWithUpdate author={author} testIdName="author-name" testIdBtn="update-btn" newName="Updated Name" />}
 						</HasOne>
 					</div>
@@ -453,8 +453,8 @@ describe('HasOne component', () => {
 
 				return (
 					<div>
-						<span data-testid="author-id">{article.author.$id ?? 'null'}</span>
-						<HasOne field={article.author}>
+						<span data-testid="author-id">{article.author!.$id ?? 'null'}</span>
+						<HasOne field={article.author!}>
 							{author => <AuthorName author={author} testId="author-name" />}
 						</HasOne>
 					</div>
diff --git a/tests/react/relations/hasOne/connect.test.tsx b/tests/react/relations/hasOne/connect.test.tsx
index 3aa96fa..4754703 100644
--- a/tests/react/relations/hasOne/connect.test.tsx
+++ b/tests/react/relations/hasOne/connect.test.tsx
@@ -5,7 +5,6 @@ import React from 'react'
 import {
 	BindxProvider,
 	MockAdapter,
-	isPlaceholderId,
 	isPersistedId,
 	useEntity,
 	useEntityList,
@@ -32,14 +31,16 @@ describe('HasOne Relations - Connect Operations', () => {
 				return <div data-testid="loading">Loading...</div>
 			}
 
+			const authorHandle = article.$hasOne('author')
+
 			return (
 				<div>
-					<span data-testid="author-id">{article.author.$id ?? 'null'}</span>
-					<span data-testid="author-name">{article.author.$entity.$fields.name.value ?? 'N/A'}</span>
-					<span data-testid="is-dirty">{article.author.$isDirty ? 'dirty' : 'clean'}</span>
+					<span data-testid="author-id">{article.author?.$id ?? 'null'}</span>
+					<span data-testid="author-name">{article.author?.$entity.$fields.name.value ?? 'N/A'}</span>
+					<span data-testid="is-dirty">{authorHandle.$isDirty ? 'dirty' : 'clean'}</span>
 					<button
 						data-testid="connect-author-2"
-						onClick={() => article.author.$connect('author-2')}
+						onClick={() => authorHandle.$connect('author-2')}
 					>
 						Connect author-2
 					</button>
@@ -87,18 +88,20 @@ describe('HasOne Relations - Connect Operations', () => {
 				return <div data-testid="loading">Loading...</div>
 			}
 
+			const authorHandle = article.$hasOne('author')
+
 			return (
 				<div>
-					<span data-testid="author-id">{article.author.$id ?? 'null'}</span>
+					<span data-testid="author-id">{article.author?.$id ?? 'null'}</span>
 					<button
 						data-testid="connect-author-2"
-						onClick={() => article.author.$connect('author-2')}
+						onClick={() => authorHandle.$connect('author-2')}
 					>
 						Connect
 					</button>
 					<button
 						data-testid="disconnect"
-						onClick={() => article.author.$disconnect()}
+						onClick={() => authorHandle.$disconnect()}
 					>
 						Disconnect
 					</button>
@@ -128,7 +131,8 @@ describe('HasOne Relations - Connect Operations', () => {
 			;(getByTestId(container, 'disconnect') as HTMLButtonElement).click()
 		})
 
-		expect(isPlaceholderId(getByTestId(container, 'author-id').textContent!)).toBe(true)
+		// Nullable has-one returns null when disconnected
+		expect(getByTestId(container, 'author-id').textContent).toBe('null')
 	})
 
 	test('4. Disconnect + Connect different - new entity should be connected', async () => {
@@ -146,18 +150,20 @@ describe('HasOne Relations - Connect Operations', () => {
 				return <div data-testid="loading">Loading...</div>
 			}
 
+			const authorHandle = article.$hasOne('author')
+
 			return (
 				<div>
-					<span data-testid="author-id">{article.author.$id ?? 'null'}</span>
+					<span data-testid="author-id">{article.author?.$id ?? 'null'}</span>
 					<button
 						data-testid="disconnect"
-						onClick={() => article.author.$disconnect()}
+						onClick={() => authorHandle.$disconnect()}
 					>
 						Disconnect
 					</button>
 					<button
 						data-testid="connect-author-2"
-						onClick={() => article.author.$connect('author-2')}
+						onClick={() => authorHandle.$connect('author-2')}
 					>
 						Connect author-2
 					</button>
@@ -183,7 +189,8 @@ describe('HasOne Relations - Connect Operations', () => {
 			;(getByTestId(container, 'disconnect') as HTMLButtonElement).click()
 		})
 
-		expect(isPlaceholderId(getByTestId(container, 'author-id').textContent!)).toBe(true)
+		// Nullable has-one returns null when disconnected
+		expect(getByTestId(container, 'author-id').textContent).toBe('null')
 
 		// Connect to author-2
 		act(() => {
@@ -208,18 +215,20 @@ describe('HasOne Relations - Connect Operations', () => {
 				return <div data-testid="loading">Loading...</div>
 			}
 
+			const authorHandle = article.$hasOne('author')
+
 			return (
 				<div>
-					<span data-testid="author-id">{article.author.$id ?? 'null'}</span>
+					<span data-testid="author-id">{article.author?.$id ?? 'null'}</span>
 					<button
 						data-testid="connect-author-1"
-						onClick={() => article.author.$connect('author-1')}
+						onClick={() => authorHandle.$connect('author-1')}
 					>
 						Connect author-1
 					</button>
 					<button
 						data-testid="connect-author-2"
-						onClick={() => article.author.$connect('author-2')}
+						onClick={() => authorHandle.$connect('author-2')}
 					>
 						Connect author-2
 					</button>
@@ -271,16 +280,18 @@ describe('HasOne Relations - Connect Operations', () => {
 				return <div>Error</div>
 			}
 
+			const authorHandle = article.$hasOne('author')
+
 			return (
 				<div>
-					<span data-testid="author-id">{article.author.$id ?? 'null'}</span>
-					<span data-testid="author-name">{article.author.$entity.$fields.name.value ?? 'N/A'}</span>
+					<span data-testid="author-id">{article.author?.$id ?? 'null'}</span>
+					<span data-testid="author-name">{article.author?.$entity.$fields.name.value ?? 'N/A'}</span>
 					<select
 						data-testid="author-select"
-						value={article.author.$id ?? ''}
+						value={article.author?.$id ?? ''}
 						onChange={e => {
 							if (e.target.value) {
-								article.author.$connect(e.target.value)
+								authorHandle.$connect(e.target.value)
 							}
 						}}
 					>
@@ -338,10 +349,10 @@ describe('HasOne Relations - Connect Operations', () => {
 				return <div>Error</div>
 			}
 
-			// Pattern from ArticleWithAuthorSelectExample
-			const currentAuthorId = article.author.$id
-			const isConnected = isPersistedId(currentAuthorId)
-			const authorEntity = article.author.$entity
+			const authorHandle = article.$hasOne('author')
+			const author = article.author
+			const currentAuthorId = author?.$id
+			const isConnected = currentAuthorId !== undefined && isPersistedId(currentAuthorId)
 
 			return (
 				<div>
@@ -350,9 +361,9 @@ describe('HasOne Relations - Connect Operations', () => {
 						value={isConnected ? currentAuthorId : ''}
 						onChange={e => {
 							if (e.target.value === '') {
-								article.author.$disconnect()
+								authorHandle.$disconnect()
 							} else {
-								article.author.$connect(e.target.value)
+								authorHandle.$connect(e.target.value)
 							}
 						}}
 					>
@@ -363,9 +374,9 @@ describe('HasOne Relations - Connect Operations', () => {
 							</option>
 						))}
 					</select>
-					<span data-testid="author-id">{currentAuthorId}</span>
+					<span data-testid="author-id">{currentAuthorId ?? 'null'}</span>
 					<span data-testid="author-name">
-						{isConnected ? authorEntity.$fields.name.value : 'N/A'}
+						{isConnected ? author?.$entity.$fields.name.value : 'N/A'}
 					</span>
 				</div>
 			)
@@ -400,7 +411,8 @@ describe('HasOne Relations - Connect Operations', () => {
 			select.value = ''
 			select.dispatchEvent(new Event('change', { bubbles: true }))
 		})
-		expect(isPlaceholderId(getByTestId(container, 'author-id').textContent!)).toBe(true)
+		// Nullable has-one returns null when disconnected
+		expect(getByTestId(container, 'author-id').textContent).toBe('null')
 		expect(getByTestId(container, 'author-name').textContent).toBe('N/A')
 
 		// Reconnect to author-1
diff --git a/tests/react/relations/hasOne/dirtyState.test.tsx b/tests/react/relations/hasOne/dirtyState.test.tsx
index 28ba6a4..2c9a0e7 100644
--- a/tests/react/relations/hasOne/dirtyState.test.tsx
+++ b/tests/react/relations/hasOne/dirtyState.test.tsx
@@ -5,7 +5,6 @@ import React from 'react'
 import {
 	BindxProvider,
 	MockAdapter,
-	isPlaceholderId,
 	useEntity,
 	useEntityList,
 } from '@contember/bindx-react'
@@ -32,14 +31,16 @@ describe('HasOne Relations - Dirty State Tracking', () => {
 				return <div>Error</div>
 			}
 
+			const authorHandle = article.$hasOne('author')
+
 			return (
 				<div>
-					<span data-testid="author-id">{article.author.$id ?? 'null'}</span>
-					<span data-testid="relation-dirty">{article.author.$isDirty ? 'dirty' : 'clean'}</span>
+					<span data-testid="author-id">{article.author?.$id ?? 'null'}</span>
+					<span data-testid="relation-dirty">{authorHandle.$isDirty ? 'dirty' : 'clean'}</span>
 					<span data-testid="entity-dirty">{article.$isDirty ? 'dirty' : 'clean'}</span>
 					<button
 						data-testid="connect-author-2"
-						onClick={() => article.author.$connect('author-2')}
+						onClick={() => authorHandle.$connect('author-2')}
 					>
 						Connect Author 2
 					</button>
@@ -88,14 +89,16 @@ describe('HasOne Relations - Dirty State Tracking', () => {
 				return <div data-testid="loading">Loading...</div>
 			}
 
+			const authorHandle = article.$hasOne('author')
+
 			return (
 				<div>
-					<span data-testid="author-id">{article.author.$id ?? 'null'}</span>
-					<span data-testid="relation-dirty">{article.author.$isDirty ? 'dirty' : 'clean'}</span>
+					<span data-testid="author-id">{article.author?.$id ?? 'null'}</span>
+					<span data-testid="relation-dirty">{authorHandle.$isDirty ? 'dirty' : 'clean'}</span>
 					<span data-testid="entity-dirty">{article.$isDirty ? 'dirty' : 'clean'}</span>
 					<button
 						data-testid="disconnect"
-						onClick={() => article.author.$disconnect()}
+						onClick={() => authorHandle.$disconnect()}
 					>
 						Disconnect
 					</button>
@@ -123,8 +126,8 @@ describe('HasOne Relations - Dirty State Tracking', () => {
 			;(getByTestId(container, 'disconnect') as HTMLButtonElement).click()
 		})
 
-		// Should be dirty
-		expect(isPlaceholderId(getByTestId(container, 'author-id').textContent!)).toBe(true)
+		// Nullable has-one returns null when disconnected
+		expect(getByTestId(container, 'author-id').textContent).toBe('null')
 		expect(getByTestId(container, 'relation-dirty').textContent).toBe('dirty')
 		expect(getByTestId(container, 'entity-dirty').textContent).toBe('dirty')
 	})
@@ -145,19 +148,21 @@ describe('HasOne Relations - Dirty State Tracking', () => {
 				return <div>Error</div>
 			}
 
+			const authorHandle = article.$hasOne('author')
+
 			return (
 				<div>
-					<span data-testid="author-id">{article.author.$id ?? 'null'}</span>
-					<span data-testid="relation-dirty">{article.author.$isDirty ? 'dirty' : 'clean'}</span>
+					<span data-testid="author-id">{article.author?.$id ?? 'null'}</span>
+					<span data-testid="relation-dirty">{authorHandle.$isDirty ? 'dirty' : 'clean'}</span>
 					<button
 						data-testid="connect-author-2"
-						onClick={() => article.author.$connect('author-2')}
+						onClick={() => authorHandle.$connect('author-2')}
 					>
 						Connect Author 2
 					</button>
 					<button
 						data-testid="connect-author-1"
-						onClick={() => article.author.$connect('author-1')}
+						onClick={() => authorHandle.$connect('author-1')}
 					>
 						Connect Author 1
 					</button>
@@ -207,14 +212,16 @@ describe('HasOne Relations - Dirty State Tracking', () => {
 				return <div>Error</div>
 			}
 
+			const authorHandle = article.$hasOne('author')
+
 			return (
 				<div>
-					<span data-testid="author-id">{article.author.$id ?? 'null'}</span>
-					<span data-testid="relation-dirty">{article.author.$isDirty ? 'dirty' : 'clean'}</span>
+					<span data-testid="author-id">{article.author?.$id ?? 'null'}</span>
+					<span data-testid="relation-dirty">{authorHandle.$isDirty ? 'dirty' : 'clean'}</span>
 					<span data-testid="entity-dirty">{article.$isDirty ? 'dirty' : 'clean'}</span>
 					<button
 						data-testid="connect-author-2"
-						onClick={() => article.author.$connect('author-2')}
+						onClick={() => authorHandle.$connect('author-2')}
 					>
 						Connect Author 2
 					</button>
@@ -274,19 +281,21 @@ describe('HasOne Relations - Dirty State Tracking', () => {
 				return <div>Error</div>
 			}
 
+			const authorHandle = article.$hasOne('author')
+
 			return (
 				<div>
-					<span data-testid="author-id">{article.author.$id ?? 'null'}</span>
-					<span data-testid="relation-dirty">{article.author.$isDirty ? 'dirty' : 'clean'}</span>
+					<span data-testid="author-id">{article.author?.$id ?? 'null'}</span>
+					<span data-testid="relation-dirty">{authorHandle.$isDirty ? 'dirty' : 'clean'}</span>
 					<button
 						data-testid="disconnect"
-						onClick={() => article.author.$disconnect()}
+						onClick={() => authorHandle.$disconnect()}
 					>
 						Disconnect
 					</button>
 					<button
 						data-testid="connect-author-1"
-						onClick={() => article.author.$connect('author-1')}
+						onClick={() => authorHandle.$connect('author-1')}
 					>
 						Connect Author 1
 					</button>
@@ -312,7 +321,8 @@ describe('HasOne Relations - Dirty State Tracking', () => {
 		act(() => {
 			;(getByTestId(container, 'disconnect') as HTMLButtonElement).click()
 		})
-		expect(isPlaceholderId(getByTestId(container, 'author-id').textContent!)).toBe(true)
+		// Nullable has-one returns null when disconnected
+		expect(getByTestId(container, 'author-id').textContent).toBe('null')
 		expect(getByTestId(container, 'relation-dirty').textContent).toBe('dirty')
 
 		// Connect back to original - should be clean
@@ -338,15 +348,17 @@ describe('HasOne Relations - Dirty State Tracking', () => {
 				return <div>Error</div>
 			}
 
+			const authorHandle = article.$hasOne('author')
+
 			return (
 				<div>
-					<span data-testid="author-name">{article.author.$fields.name.value}</span>
-					<span data-testid="author-field-dirty">{article.author.$fields.name.isDirty ? 'dirty' : 'clean'}</span>
-					<span data-testid="relation-dirty">{article.author.$isDirty ? 'dirty' : 'clean'}</span>
+					<span data-testid="author-name">{article.author?.$fields.name.value}</span>
+					<span data-testid="author-field-dirty">{article.author?.$fields.name.isDirty ? 'dirty' : 'clean'}</span>
+					<span data-testid="relation-dirty">{authorHandle.$isDirty ? 'dirty' : 'clean'}</span>
 					<span data-testid="entity-dirty">{article.$isDirty ? 'dirty' : 'clean'}</span>
 					<button
 						data-testid="change-name"
-						onClick={() => article.author.$fields.name.setValue('Updated Name')}
+						onClick={() => authorHandle.$entity.$fields.name.setValue('Updated Name')}
 					>
 						Change Name
 					</button>
@@ -399,18 +411,20 @@ describe('HasOne Relations - Dirty State Tracking', () => {
 				return <div>Error</div>
 			}
 
+			const authorHandle = article.$hasOne('author')
+
 			return (
 				<div>
 					<span data-testid="entity-dirty">{article.$isDirty ? 'dirty' : 'clean'}</span>
 					<button
 						data-testid="connect-author-2"
-						onClick={() => article.author.$connect('author-2')}
+						onClick={() => authorHandle.$connect('author-2')}
 					>
 						Connect Author 2
 					</button>
 					<button
 						data-testid="connect-author-1"
-						onClick={() => article.author.$connect('author-1')}
+						onClick={() => authorHandle.$connect('author-1')}
 					>
 						Connect Author 1
 					</button>
diff --git a/tests/react/relations/hasOne/disconnect.test.tsx b/tests/react/relations/hasOne/disconnect.test.tsx
index 22ae4ed..38bba19 100644
--- a/tests/react/relations/hasOne/disconnect.test.tsx
+++ b/tests/react/relations/hasOne/disconnect.test.tsx
@@ -5,7 +5,6 @@ import React from 'react'
 import {
 	BindxProvider,
 	MockAdapter,
-	isPlaceholderId,
 	useEntity,
 } from '@contember/bindx-react'
 import { getByTestId, queryByTestId, createMockData, entityDefs, schema } from './setup'
@@ -15,7 +14,7 @@ afterEach(() => {
 })
 
 describe('HasOne Relations - Disconnect Operations', () => {
-	test('2. Disconnect - entity should become null/placeholder, isDirty=true', async () => {
+	test('2. Disconnect - entity should become null, isDirty=true', async () => {
 		const adapter = new MockAdapter(createMockData(), { delay: 0 })
 
 		function TestComponent(): React.ReactElement {
@@ -30,13 +29,15 @@ describe('HasOne Relations - Disconnect Operations', () => {
 				return <div data-testid="loading">Loading...</div>
 			}
 
+			const authorHandle = article.$hasOne('author')
+
 			return (
 				<div>
-					<span data-testid="author-id">{article.author.$id ?? 'null'}</span>
-					<span data-testid="is-dirty">{article.author.$isDirty ? 'dirty' : 'clean'}</span>
+					<span data-testid="author-id">{article.author?.$id ?? 'null'}</span>
+					<span data-testid="is-dirty">{authorHandle.$isDirty ? 'dirty' : 'clean'}</span>
 					<button
 						data-testid="disconnect"
-						onClick={() => article.author.$disconnect()}
+						onClick={() => authorHandle.$disconnect()}
 					>
 						Disconnect
 					</button>
@@ -63,12 +64,12 @@ describe('HasOne Relations - Disconnect Operations', () => {
 			;(getByTestId(container, 'disconnect') as HTMLButtonElement).click()
 		})
 
-		// Should now be null
-		expect(isPlaceholderId(getByTestId(container, 'author-id').textContent!)).toBe(true)
+		// Nullable has-one returns null when disconnected
+		expect(getByTestId(container, 'author-id').textContent).toBe('null')
 		expect(getByTestId(container, 'is-dirty').textContent).toBe('dirty')
 	})
 
-	test('8. Placeholder fields - can write to placeholder fields when disconnected', async () => {
+	test('8. Placeholder fields - can write to placeholder fields via $hasOne when disconnected', async () => {
 		const adapter = new MockAdapter(createMockData(), { delay: 0 })
 
 		function TestComponent(): React.ReactElement {
@@ -83,15 +84,19 @@ describe('HasOne Relations - Disconnect Operations', () => {
 				return <div data-testid="loading">Loading...</div>
 			}
 
+			// Nullable has-one returns null when disconnected
+			// Use $hasOne to access placeholder entity for writes
+			const authorHandle = article.$hasOne('author')
+
 			return (
 				<div>
-					<span data-testid="author-id">{article.author.$id ?? 'null'}</span>
+					<span data-testid="author-null">{article.author === null ? 'yes' : 'no'}</span>
 					<span data-testid="placeholder-name">
-						{article.author.$entity.$fields.name.value ?? 'empty'}
+						{authorHandle.$entity.$fields.name.value ?? 'empty'}
 					</span>
 					<button
 						data-testid="set-name"
-						onClick={() => article.author.$entity.$fields.name.setValue('New Author')}
+						onClick={() => authorHandle.$entity.$fields.name.setValue('New Author')}
 					>
 						Set Name
 					</button>
@@ -106,14 +111,14 @@ describe('HasOne Relations - Disconnect Operations', () => {
 		)
 
 		await waitFor(() => {
-			expect(queryByTestId(container, 'author-id')).not.toBeNull()
+			expect(queryByTestId(container, 'author-null')).not.toBeNull()
 		})
 
-		// No author initially
-		expect(isPlaceholderId(getByTestId(container, 'author-id').textContent!)).toBe(true)
+		// No author initially — nullable has-one returns null
+		expect(getByTestId(container, 'author-null').textContent).toBe('yes')
 		expect(getByTestId(container, 'placeholder-name').textContent).toBe('empty')
 
-		// Set placeholder name
+		// Set placeholder name via $hasOne handle
 		act(() => {
 			;(getByTestId(container, 'set-name') as HTMLButtonElement).click()
 		})
@@ -139,11 +144,11 @@ describe('HasOne Relations - Disconnect Operations', () => {
 
 			return (
 				<div>
-					<span data-testid="author-name">{article.author.$entity.$fields.name.value ?? 'N/A'}</span>
-					<span data-testid="author-email">{article.author.$entity.$fields.email.value ?? 'N/A'}</span>
+					<span data-testid="author-name">{article.author?.$entity.$fields.name.value ?? 'N/A'}</span>
+					<span data-testid="author-email">{article.author?.$entity.$fields.email.value ?? 'N/A'}</span>
 					<button
 						data-testid="set-name"
-						onClick={() => article.author.$entity.$fields.name.setValue('Jane Updated')}
+						onClick={() => article.$hasOne('author').$entity.$fields.name.setValue('Jane Updated')}
 					>
 						Set Name
 					</button>
@@ -188,15 +193,17 @@ describe('HasOne Relations - Disconnect Operations', () => {
 				return <div data-testid="loading">Loading...</div>
 			}
 
+			const authorHandle = article.$hasOne('author')
+
 			return (
 				<div>
-					<span data-testid="author-name">{article.author.$entity.$fields.name.value ?? 'N/A'}</span>
-					<span data-testid="author-email">{article.author.$entity.$fields.email.value ?? 'N/A'}</span>
+					<span data-testid="author-name">{article.author?.$entity.$fields.name.value ?? 'N/A'}</span>
+					<span data-testid="author-email">{article.author?.$entity.$fields.email.value ?? 'N/A'}</span>
 					<button
 						data-testid="set-both"
 						onClick={() => {
-							article.author.$entity.$fields.name.setValue('New Name')
-							article.author.$entity.$fields.email.setValue('new@email.com')
+							authorHandle.$entity.$fields.name.setValue('New Name')
+							authorHandle.$entity.$fields.email.setValue('new@email.com')
 						}}
 					>
 						Set Both
diff --git a/tests/react/relations/hasOne/persist.test.tsx b/tests/react/relations/hasOne/persist.test.tsx
index 56b87b8..01ff1c9 100644
--- a/tests/react/relations/hasOne/persist.test.tsx
+++ b/tests/react/relations/hasOne/persist.test.tsx
@@ -5,7 +5,6 @@ import React from 'react'
 import {
 	BindxProvider,
 	MockAdapter,
-	isPlaceholderId,
 	useEntity,
 	useEntityList,
 } from '@contember/bindx-react'
@@ -32,14 +31,16 @@ describe('HasOne Relations - Persistence', () => {
 				return <div>Error</div>
 			}
 
+			const authorHandle = article.$hasOne('author')
+
 			return (
 				<div>
-					<span data-testid="author-id">{article.author.$id ?? 'null'}</span>
+					<span data-testid="author-id">{article.author?.$id ?? 'null'}</span>
 					<span data-testid="is-dirty">{article.$isDirty ? 'dirty' : 'clean'}</span>
 					<span data-testid="is-persisting">idle</span>
 					<button
 						data-testid="connect-author-2"
-						onClick={() => article.author.$connect('author-2')}
+						onClick={() => authorHandle.$connect('author-2')}
 					>
 						Connect Author 2
 					</button>
@@ -101,11 +102,13 @@ describe('HasOne Relations - Persistence', () => {
 				return <div data-testid="loading">Loading...</div>
 			}
 
+			const authorHandle = article.$hasOne('author')
+
 			return (
 				<div>
-					<span data-testid="author-id">{article.author.$id ?? 'null'}</span>
+					<span data-testid="author-id">{article.author?.$id ?? 'null'}</span>
 					<span data-testid="is-dirty">{article.$isDirty ? 'dirty' : 'clean'}</span>
-					<button data-testid="disconnect" onClick={() => article.author.$disconnect()}>
+					<button data-testid="disconnect" onClick={() => authorHandle.$disconnect()}>
 						Disconnect
 					</button>
 					<button data-testid="persist" onClick={() => article.$persist()}>
@@ -132,7 +135,8 @@ describe('HasOne Relations - Persistence', () => {
 		act(() => {
 			;(getByTestId(container, 'disconnect') as HTMLButtonElement).click()
 		})
-		expect(isPlaceholderId(getByTestId(container, 'author-id').textContent!)).toBe(true)
+		// Nullable has-one returns null when disconnected
+		expect(getByTestId(container, 'author-id').textContent).toBe('null')
 		expect(getByTestId(container, 'is-dirty').textContent).toBe('dirty')
 
 		// Persist changes
diff --git a/tests/react/relations/hasOne/reset.test.tsx b/tests/react/relations/hasOne/reset.test.tsx
index 62b11c5..3f449e1 100644
--- a/tests/react/relations/hasOne/reset.test.tsx
+++ b/tests/react/relations/hasOne/reset.test.tsx
@@ -5,7 +5,6 @@ import React from 'react'
 import {
 	BindxProvider,
 	MockAdapter,
-	isPlaceholderId,
 	useEntity,
 } from '@contember/bindx-react'
 import { getByTestId, queryByTestId, createMockData, entityDefs, schema } from './setup'
@@ -30,17 +29,19 @@ describe('HasOne Relations - Reset Operations', () => {
 				return <div data-testid="loading">Loading...</div>
 			}
 
+			const authorHandle = article.$hasOne('author')
+
 			return (
 				<div>
-					<span data-testid="author-id">{article.author.$id ?? 'null'}</span>
-					<span data-testid="is-dirty">{article.author.$isDirty ? 'dirty' : 'clean'}</span>
+					<span data-testid="author-id">{article.author?.$id ?? 'null'}</span>
+					<span data-testid="is-dirty">{authorHandle.$isDirty ? 'dirty' : 'clean'}</span>
 					<button
 						data-testid="connect-author-2"
-						onClick={() => article.author.$connect('author-2')}
+						onClick={() => authorHandle.$connect('author-2')}
 					>
 						Connect
 					</button>
-					<button data-testid="reset" onClick={() => article.author.$reset()}>
+					<button data-testid="reset" onClick={() => authorHandle.$reset()}>
 						Reset
 					</button>
 				</div>
@@ -90,17 +91,19 @@ describe('HasOne Relations - Reset Operations', () => {
 				return <div data-testid="loading">Loading...</div>
 			}
 
+			const authorHandle = article.$hasOne('author')
+
 			return (
 				<div>
-					<span data-testid="author-id">{article.author.$id ?? 'null'}</span>
-					<span data-testid="is-dirty">{article.author.$isDirty ? 'dirty' : 'clean'}</span>
+					<span data-testid="author-id">{article.author?.$id ?? 'null'}</span>
+					<span data-testid="is-dirty">{authorHandle.$isDirty ? 'dirty' : 'clean'}</span>
 					<button
 						data-testid="disconnect"
-						onClick={() => article.author.$disconnect()}
+						onClick={() => authorHandle.$disconnect()}
 					>
 						Disconnect
 					</button>
-					<button data-testid="reset" onClick={() => article.author.$reset()}>
+					<button data-testid="reset" onClick={() => authorHandle.$reset()}>
 						Reset
 					</button>
 				</div>
@@ -122,7 +125,8 @@ describe('HasOne Relations - Reset Operations', () => {
 			;(getByTestId(container, 'disconnect') as HTMLButtonElement).click()
 		})
 
-		expect(isPlaceholderId(getByTestId(container, 'author-id').textContent!)).toBe(true)
+		// Nullable has-one returns null when disconnected
+		expect(getByTestId(container, 'author-id').textContent).toBe('null')
 		expect(getByTestId(container, 'is-dirty').textContent).toBe('dirty')
 
 		// Reset
diff --git a/tests/react/relations/hasOne/setup.ts b/tests/react/relations/hasOne/setup.ts
index 9d2c280..25f2829 100644
--- a/tests/react/relations/hasOne/setup.ts
+++ b/tests/react/relations/hasOne/setup.ts
@@ -35,7 +35,7 @@ export const schema = defineSchema<TestSchema>({
 			fields: {
 				id: scalar(),
 				title: scalar(),
-				author: hasOne('Author'),
+				author: hasOne('Author', { nullable: true }),
 			},
 		},
 		Author: {