Kundeninventar-Nummern kollisionsfrei vergeben

backend/src/routes/resources/main.ts

@@ -1035,7 +1035,25 @@ export default async function resourceRoutes(server: FastifyInstance) {
 
             if (config.numberRangeHolder && !body[config.numberRangeHolder]) {
                 const numberRangeResource = resource === "members" ? "customers" : resource
-                const result = await useNextNumberRangeNumber(server, req.user.tenant_id, numberRangeResource)
+                const numberRangeColumn = table[config.numberRangeHolder]
+                const tenantColumn = getTenantColumn(resource, table)
+                const result = await useNextNumberRangeNumber(
+                    server,
+                    req.user.tenant_id,
+                    numberRangeResource,
+                    async (candidate, tx) => {
+                        const existing = await tx
+                            .select({ id: table.id })
+                            .from(table)
+                            .where(and(
+                                eq(tenantColumn, req.user!.tenant_id),
+                                eq(numberRangeColumn, candidate)
+                            ))
+                            .limit(1)
+
+                        return existing.length === 0
+                    }
+                )
                 createData[config.numberRangeHolder] = result.usedNumber
             }