diff --git a/packages/3-extensions/sql-orm-client/src/collection-contract.ts b/packages/3-extensions/sql-orm-client/src/collection-contract.ts
index e139a58181..ee0569536d 100644
--- a/packages/3-extensions/sql-orm-client/src/collection-contract.ts
+++ b/packages/3-extensions/sql-orm-client/src/collection-contract.ts
@@ -322,6 +322,25 @@ export function resolvePrimaryKeyColumn(contract: Contract<SqlStorage>, tableNam
   return contract.storage.tables[tableName]?.primaryKey?.columns[0] ?? 'id';
 }
 
+export function resolveRowIdentityColumns(
+  contract: Contract<SqlStorage>,
+  tableName: string,
+): readonly string[] {
+  const table = contract.storage.tables[tableName];
+  if (!table) {
+    return [];
+  }
+  if (table.primaryKey && table.primaryKey.columns.length > 0) {
+    return table.primaryKey.columns;
+  }
+  for (const unique of table.uniques) {
+    if (unique.columns.length > 0) {
+      return unique.columns;
+    }
+  }
+  return [];
+}
+
 export function assertReturningCapability(contract: Contract<SqlStorage>, action: string): void {
   if (hasContractCapability(contract, 'returning')) {
     return;
diff --git a/packages/3-extensions/sql-orm-client/src/collection.ts b/packages/3-extensions/sql-orm-client/src/collection.ts
index 2367ae3523..29ee044b2a 100644
--- a/packages/3-extensions/sql-orm-client/src/collection.ts
+++ b/packages/3-extensions/sql-orm-client/src/collection.ts
@@ -2,6 +2,7 @@ import type { Contract } from '@prisma-next/contract/types';
 import { AsyncIterableResult } from '@prisma-next/framework-components/runtime';
 import type { SqlStorage } from '@prisma-next/sql-contract/types';
 import {
+  type AnyExpression,
   BinaryExpr,
   ColumnRef,
   isWhereExpr,
@@ -25,6 +26,7 @@ import {
   resolveModelTableName,
   resolvePolymorphismInfo,
   resolvePrimaryKeyColumn,
+  resolveRowIdentityColumns,
   resolveUpsertConflictColumns,
 } from './collection-contract';
 import { dispatchCollectionRows } from './collection-dispatch';
@@ -107,6 +109,7 @@ import {
   type RelatedModelName,
   type RelationNames,
   type ResolvedCreateInput,
+  type RuntimeQueryable,
   type ShorthandWhereFilter,
   type UniqueConstraintCriterion,
   type VariantModelRow,
@@ -1038,12 +1041,20 @@ export class Collection<
       return this.#reloadMutationRowByPrimaryKey(pkCriterion);
     }
 
-    const rows = await this.updateAll(
-      data as State['hasWhere'] extends true
-        ? Partial<DefaultModelRow<TContract, ModelName>>
-        : never,
-    );
-    return rows[0] ?? null;
+    return withMutationScope(this.ctx.runtime, async (scope) => {
+      const scoped = this.#withRuntime(scope);
+      const identityWhere = await scoped.#findFirstMatchingRowIdentityWhere();
+      if (!identityWhere) {
+        return null;
+      }
+      const narrowed = scoped.#clone({ filters: [identityWhere] });
+      const rows = await narrowed.updateAll(
+        data as State['hasWhere'] extends true
+          ? Partial<DefaultModelRow<TContract, ModelName>>
+          : never,
+      );
+      return rows[0] ?? null;
+    });
   }
 
   updateAll(
@@ -1115,15 +1126,26 @@ export class Collection<
     this: State['hasWhere'] extends true ? Collection<TContract, ModelName, Row, State> : never,
   ): Promise<Row | null> {
     assertReturningCapability(this.contract, 'delete()');
-    const rows = await this.deleteAll().toArray();
-    return rows[0] ?? null;
+    return withMutationScope(this.ctx.runtime, async (scope) => {
+      const scoped = this.#withRuntime(scope);
+      const identityWhere = await scoped.#findFirstMatchingRowIdentityWhere();
+      if (!identityWhere) {
+        return null;
+      }
+      const narrowed = scoped.#clone({ filters: [identityWhere] });
+      const rows = await narrowed.#executeDeleteReturning().toArray();
+      return rows[0] ?? null;
+    });
   }
 
   deleteAll(
     this: State['hasWhere'] extends true ? Collection<TContract, ModelName, Row, State> : never,
   ): AsyncIterableResult<Row> {
     assertReturningCapability(this.contract, 'deleteAll()');
+    return this.#executeDeleteReturning();
+  }
 
+  #executeDeleteReturning(): AsyncIterableResult<Row> {
     const parentJoinColumns = this.state.includes.map((include) => include.localColumn);
     const { selectedForQuery: selectedForDelete, hiddenColumns } = augmentSelectionForJoinColumns(
       this.state.selectedFields,
@@ -1188,6 +1210,41 @@ export class Collection<
     return criterion;
   }
 
+  async #findFirstMatchingRowIdentityWhere(): Promise<AnyExpression | null> {
+    const identityColumns = resolveRowIdentityColumns(this.contract, this.tableName);
+    if (identityColumns.length === 0) {
+      throw new Error(
+        `update()/delete() on model "${this.modelName}" requires the table to have a primary key or unique constraint`,
+      );
+    }
+    const firstRow = await this.#clone({
+      selectedFields: [...identityColumns],
+      includes: [],
+    }).first();
+    if (!firstRow) {
+      return null;
+    }
+    const columnToField = getColumnToFieldMap(this.contract, this.modelName);
+    const criterion: Record<string, unknown> = {};
+    for (const column of identityColumns) {
+      const fieldName = columnToField[column] ?? column;
+      const value = (firstRow as Record<string, unknown>)[fieldName];
+      if (value === undefined) {
+        throw new Error(
+          `Missing identity field "${fieldName}" while resolving single-row scope for model "${this.modelName}"`,
+        );
+      }
+      criterion[fieldName] = value;
+    }
+    return (
+      shorthandToWhereExpr(
+        this.ctx.context,
+        this.modelName,
+        criterion as ShorthandWhereFilter<TContract, ModelName>,
+      ) ?? null
+    );
+  }
+
   async #reloadMutationRowByPrimaryKey(criterion: Record<string, unknown>): Promise<Row | null> {
     return this.#reloadMutationRowByCriterion(criterion, 'primary key');
   }
@@ -1242,6 +1299,16 @@ export class Collection<
     });
   }
 
+  #withRuntime(runtime: RuntimeQueryable): Collection<TContract, ModelName, Row, State> {
+    const Ctor = this.constructor as CollectionConstructor<TContract>;
+    return new Ctor({ ...this.ctx, runtime }, this.modelName, {
+      tableName: this.tableName,
+      state: this.state,
+      registry: this.registry,
+      includeRefinementMode: this.includeRefinementMode,
+    }) as unknown as Collection<TContract, ModelName, Row, State>;
+  }
+
   #cloneWithRow<NextRow, NextState extends CollectionTypeState = State>(
     overrides: Partial<CollectionState>,
   ): Collection<TContract, ModelName, NextRow, NextState> {
diff --git a/packages/3-extensions/sql-orm-client/test/collection-contract.test.ts b/packages/3-extensions/sql-orm-client/test/collection-contract.test.ts
index f74ccbc6ce..5f0edc5326 100644
--- a/packages/3-extensions/sql-orm-client/test/collection-contract.test.ts
+++ b/packages/3-extensions/sql-orm-client/test/collection-contract.test.ts
@@ -7,6 +7,7 @@ import {
   resolveModelTableName,
   resolvePolymorphismInfo,
   resolvePrimaryKeyColumn,
+  resolveRowIdentityColumns,
   resolveUpsertConflictColumns,
 } from '../src/collection-contract';
 import { buildMixedPolyContract, getTestContract } from './helpers';
@@ -235,6 +236,63 @@ describe('collection-contract capability detection', () => {
     expect(isToOneCardinality('M:N')).toBe(false);
     expect(isToOneCardinality(undefined)).toBe(false);
   });
+
+  describe('resolveRowIdentityColumns()', () => {
+    const buildContract = (table: {
+      primaryKey?: { columns: readonly string[] };
+      uniques?: ReadonlyArray<{ columns: readonly string[] }>;
+    }) =>
+      ({
+        storage: {
+          tables: {
+            t: {
+              primaryKey: table.primaryKey,
+              uniques: table.uniques ?? [],
+            },
+          },
+        },
+      }) as unknown as Parameters<typeof resolveRowIdentityColumns>[0];
+
+    it('returns primary key columns when present', () => {
+      expect(
+        resolveRowIdentityColumns(buildContract({ primaryKey: { columns: ['id'] } }), 't'),
+      ).toEqual(['id']);
+    });
+
+    it('returns composite primary key columns when present', () => {
+      expect(
+        resolveRowIdentityColumns(buildContract({ primaryKey: { columns: ['a', 'b'] } }), 't'),
+      ).toEqual(['a', 'b']);
+    });
+
+    it('falls back to first unique constraint when no primary key', () => {
+      expect(
+        resolveRowIdentityColumns(
+          buildContract({ uniques: [{ columns: ['email'] }, { columns: ['handle'] }] }),
+          't',
+        ),
+      ).toEqual(['email']);
+    });
+
+    it('returns composite unique columns when no primary key', () => {
+      expect(
+        resolveRowIdentityColumns(
+          buildContract({ uniques: [{ columns: ['tenant_id', 'slug'] }] }),
+          't',
+        ),
+      ).toEqual(['tenant_id', 'slug']);
+    });
+
+    it('returns empty array when neither primary key nor uniques are defined', () => {
+      expect(resolveRowIdentityColumns(buildContract({}), 't')).toEqual([]);
+    });
+
+    it('returns empty array for unknown tables', () => {
+      expect(
+        resolveRowIdentityColumns(buildContract({ primaryKey: { columns: ['id'] } }), 'missing'),
+      ).toEqual([]);
+    });
+  });
 });
 
 describe('resolvePolymorphismInfo()', () => {
diff --git a/packages/3-extensions/sql-orm-client/test/integration/delete.test.ts b/packages/3-extensions/sql-orm-client/test/integration/delete.test.ts
index 8c89c542fc..a0336d9b4a 100644
--- a/packages/3-extensions/sql-orm-client/test/integration/delete.test.ts
+++ b/packages/3-extensions/sql-orm-client/test/integration/delete.test.ts
@@ -65,6 +65,36 @@ describe('integration/delete', () => {
     timeouts.spinUpPpgDev,
   );
 
+  it(
+    'delete() affects only one row even when where() matches several',
+    async () => {
+      await withCollectionRuntime(async (runtime) => {
+        const users = createReturningUsersCollection(runtime);
+
+        await seedUsers(runtime, [
+          { id: 1, name: 'Remove', email: 'a@example.com' },
+          { id: 2, name: 'Remove', email: 'b@example.com' },
+          { id: 3, name: 'Keep', email: 'c@example.com' },
+        ]);
+
+        const returned = await users.where({ name: 'Remove' }).delete();
+
+        expect(returned).not.toBeNull();
+        expect(returned?.name).toBe('Remove');
+        expect([1, 2]).toContain(returned?.id);
+
+        const rows = await runtime.query<{ id: number; name: string }>(
+          'select id, name from users order by id',
+        );
+        const remainingRemove = rows.filter((row) => row.name === 'Remove');
+        expect(remainingRemove).toHaveLength(1);
+        expect(remainingRemove[0]?.id).not.toBe(returned?.id);
+        expect(rows).toContainEqual({ id: 3, name: 'Keep' });
+      });
+    },
+    timeouts.spinUpPpgDev,
+  );
+
   it(
     'deleteAll() returns all deleted rows',
     async () => {
diff --git a/packages/3-extensions/sql-orm-client/test/integration/update.test.ts b/packages/3-extensions/sql-orm-client/test/integration/update.test.ts
index 17dd9fda4f..084088bf7c 100644
--- a/packages/3-extensions/sql-orm-client/test/integration/update.test.ts
+++ b/packages/3-extensions/sql-orm-client/test/integration/update.test.ts
@@ -37,6 +37,38 @@ describe('integration/update', () => {
     timeouts.spinUpPpgDev,
   );
 
+  it(
+    'update() affects only one row even when where() matches several',
+    async () => {
+      await withCollectionRuntime(async (runtime) => {
+        const users = createReturningUsersCollection(runtime);
+
+        await seedUsers(runtime, [
+          { id: 1, name: 'Stale', email: 'a@example.com' },
+          { id: 2, name: 'Stale', email: 'b@example.com' },
+          { id: 3, name: 'Fresh', email: 'c@example.com' },
+        ]);
+
+        const returned = await users.where({ name: 'Stale' }).update({ name: 'Updated' });
+
+        expect(returned).not.toBeNull();
+        expect(returned?.name).toBe('Updated');
+        expect([1, 2]).toContain(returned?.id);
+
+        const rows = await runtime.query<{ id: number; name: string }>(
+          'select id, name from users order by id',
+        );
+        const updatedRows = rows.filter((row) => row.name === 'Updated');
+        const staleRows = rows.filter((row) => row.name === 'Stale');
+        expect(updatedRows).toHaveLength(1);
+        expect(staleRows).toHaveLength(1);
+        expect(rows).toContainEqual({ id: 3, name: 'Fresh' });
+        expect(updatedRows[0]?.id).toBe(returned?.id);
+      });
+    },
+    timeouts.spinUpPpgDev,
+  );
+
   it(
     'updateAll() returns all updated rows',
     async () => {