diff --git a/backend/src/config/index.ts b/backend/src/config/index.ts
index 1eee1b9a4..eed4278d2 100644
--- a/backend/src/config/index.ts
+++ b/backend/src/config/index.ts
@@ -10,7 +10,7 @@ Decimal.set({
 })
 
 const constants = {
-  DB_VERSION: '0035-admin_pending_creations_decimal',
+  DB_VERSION: '0036-unique_previous_in_transactions',
   DECAY_START_TIME: new Date('2021-05-13 17:46:31'), // GMT+0
   CONFIG_VERSION: {
     DEFAULT: 'DEFAULT',
diff --git a/backend/src/graphql/resolver/AdminResolver.test.ts b/backend/src/graphql/resolver/AdminResolver.test.ts
index 6842f09ca..ca6bf0fe7 100644
--- a/backend/src/graphql/resolver/AdminResolver.test.ts
+++ b/backend/src/graphql/resolver/AdminResolver.test.ts
@@ -1053,6 +1053,53 @@ describe('AdminResolver', () => {
               expect(transaction[0].typeId).toEqual(1)
             })
           })
+
+          describe('confirm two creations one after the other quickly', () => {
+            let c1: AdminPendingCreation | void
+            let c2: AdminPendingCreation | void
+
+            beforeAll(async () => {
+              const now = new Date()
+              c1 = await creationFactory(testEnv, {
+                email: 'bibi@bloxberg.de',
+                amount: 50,
+                memo: 'Herzlich Willkommen bei Gradido liebe Bibi!',
+                creationDate: new Date(now.getFullYear(), now.getMonth() - 2, 1).toISOString(),
+              })
+              c2 = await creationFactory(testEnv, {
+                email: 'bibi@bloxberg.de',
+                amount: 50,
+                memo: 'Herzlich Willkommen bei Gradido liebe Bibi!',
+                creationDate: new Date(now.getFullYear(), now.getMonth() - 2, 1).toISOString(),
+              })
+            })
+
+            // In the futrue this should not throw anymore
+            it('throws an error for the second confirmation', async () => {
+              const r1 = mutate({
+                mutation: confirmPendingCreation,
+                variables: {
+                  id: c1 ? c1.id : -1,
+                },
+              })
+              const r2 = mutate({
+                mutation: confirmPendingCreation,
+                variables: {
+                  id: c2 ? c2.id : -1,
+                },
+              })
+              await expect(r1).resolves.toEqual(
+                expect.objectContaining({
+                  data: { confirmPendingCreation: true },
+                }),
+              )
+              await expect(r2).resolves.toEqual(
+                expect.objectContaining({
+                  errors: [new GraphQLError('Unable to confirm creation.')],
+                }),
+              )
+            })
+          })
         })
       })
     })
diff --git a/backend/src/graphql/resolver/AdminResolver.ts b/backend/src/graphql/resolver/AdminResolver.ts
index 78cbf3fc8..8da92a61c 100644
--- a/backend/src/graphql/resolver/AdminResolver.ts
+++ b/backend/src/graphql/resolver/AdminResolver.ts
@@ -361,7 +361,9 @@ export class AdminResolver {
     transaction.balanceDate = receivedCallDate
     transaction.decay = decay ? decay.decay : new Decimal(0)
     transaction.decayStart = decay ? decay.start : null
-    await transaction.save()
+    await transaction.save().catch(() => {
+      throw new Error('Unable to confirm creation.')
+    })
 
     await AdminPendingCreation.delete(pendingCreation)
 
diff --git a/database/entity/0036-unique_previous_in_transactions/Transaction.ts b/database/entity/0036-unique_previous_in_transactions/Transaction.ts
new file mode 100644
index 000000000..99202eee4
--- /dev/null
+++ b/database/entity/0036-unique_previous_in_transactions/Transaction.ts
@@ -0,0 +1,94 @@
+import Decimal from 'decimal.js-light'
+import { BaseEntity, Entity, PrimaryGeneratedColumn, Column } from 'typeorm'
+import { DecimalTransformer } from '../../src/typeorm/DecimalTransformer'
+
+@Entity('transactions')
+export class Transaction extends BaseEntity {
+  @PrimaryGeneratedColumn('increment', { unsigned: true })
+  id: number
+
+  @Column({ name: 'user_id', unsigned: true, nullable: false })
+  userId: number
+
+  @Column({ type: 'int', unsigned: true, unique: true, nullable: true, default: null })
+  previous: number | null
+
+  @Column({ name: 'type_id', unsigned: true, nullable: false })
+  typeId: number
+
+  @Column({
+    type: 'decimal',
+    precision: 40,
+    scale: 20,
+    nullable: false,
+    transformer: DecimalTransformer,
+  })
+  amount: Decimal
+
+  @Column({
+    type: 'decimal',
+    precision: 40,
+    scale: 20,
+    nullable: false,
+    transformer: DecimalTransformer,
+  })
+  balance: Decimal
+
+  @Column({
+    name: 'balance_date',
+    type: 'datetime',
+    default: () => 'CURRENT_TIMESTAMP',
+    nullable: false,
+  })
+  balanceDate: Date
+
+  @Column({
+    type: 'decimal',
+    precision: 40,
+    scale: 20,
+    nullable: false,
+    transformer: DecimalTransformer,
+  })
+  decay: Decimal
+
+  @Column({
+    name: 'decay_start',
+    type: 'datetime',
+    nullable: true,
+    default: null,
+  })
+  decayStart: Date | null
+
+  @Column({ length: 255, nullable: false, collation: 'utf8mb4_unicode_ci' })
+  memo: string
+
+  @Column({ name: 'creation_date', type: 'datetime', nullable: true, default: null })
+  creationDate: Date | null
+
+  @Column({
+    name: 'linked_user_id',
+    type: 'int',
+    unsigned: true,
+    nullable: true,
+    default: null,
+  })
+  linkedUserId?: number | null
+
+  @Column({
+    name: 'linked_transaction_id',
+    type: 'int',
+    unsigned: true,
+    nullable: true,
+    default: null,
+  })
+  linkedTransactionId?: number | null
+
+  @Column({
+    name: 'transaction_link_id',
+    type: 'int',
+    unsigned: true,
+    nullable: true,
+    default: null,
+  })
+  transactionLinkId?: number | null
+}
diff --git a/database/entity/Transaction.ts b/database/entity/Transaction.ts
index 3515202d0..5365b0f70 100644
--- a/database/entity/Transaction.ts
+++ b/database/entity/Transaction.ts
@@ -1 +1 @@
-export { Transaction } from './0032-add-transaction-link-to-transaction/Transaction'
+export { Transaction } from './0036-unique_previous_in_transactions/Transaction'
diff --git a/database/migrations/0036-unique_previous_in_transactions.ts b/database/migrations/0036-unique_previous_in_transactions.ts
new file mode 100644
index 000000000..f05b044bb
--- /dev/null
+++ b/database/migrations/0036-unique_previous_in_transactions.ts
@@ -0,0 +1,13 @@
+/* MIGRATION TO SET previous COLUMN UNIQUE in TRANSACTION table
+ */
+
+/* eslint-disable @typescript-eslint/explicit-module-boundary-types */
+/* eslint-disable @typescript-eslint/no-explicit-any */
+
+export async function upgrade(queryFn: (query: string, values?: any[]) => Promise<Array<any>>) {
+  await queryFn('ALTER TABLE `transactions` ADD UNIQUE(`previous`);')
+}
+
+export async function downgrade(queryFn: (query: string, values?: any[]) => Promise<Array<any>>) {
+  await queryFn('ALTER TABLE  `transactions` DROP INDEX `previous`;')
+}