diff --git a/src/entity/trx_maintenance_groups.ts b/src/entity/trx_maintenance_groups.ts
index d8d23dc..806da41 100644
--- a/src/entity/trx_maintenance_groups.ts
+++ b/src/entity/trx_maintenance_groups.ts
@@ -1,4 +1,4 @@
-import { Column, CreateDateColumn, DeleteDateColumn, Entity, JoinColumn, ManyToOne, PrimaryGeneratedColumn, UpdateDateColumn } from "typeorm";
+import { Column, CreateDateColumn, DeleteDateColumn, Entity, JoinColumn, JoinTable, ManyToOne, OneToMany, PrimaryGeneratedColumn, UpdateDateColumn } from "typeorm";
 import { TrxMaintenancePosition, TrxMaintenanceStatus } from "../types/trx";
 import { TrxMaintenance } from "./trx_maintenances";
 import { Status } from "../types/status";
@@ -8,6 +8,10 @@ export class TrxMaintenanceGroup {
 	@PrimaryGeneratedColumn("uuid")
 	id: string;
 
+	@ManyToOne(() => TrxMaintenance, { onDelete: "RESTRICT" })
+	@JoinTable()
+	maintenance: TrxMaintenance;
+
 	@Column({
 		nullable: true,
 		length: 256,
diff --git a/src/entity/trx_maintenance_slas.ts b/src/entity/trx_maintenance_slas.ts
index 621c8eb..33c7013 100644
--- a/src/entity/trx_maintenance_slas.ts
+++ b/src/entity/trx_maintenance_slas.ts
@@ -1,15 +1,15 @@
 import { Column, CreateDateColumn, DeleteDateColumn, Entity, JoinColumn, ManyToOne, PrimaryGeneratedColumn, UpdateDateColumn } from "typeorm";
 import { TrxMaintenancePosition, TrxMaintenanceStatus } from "../types/trx";
-import { TrxMaintenanceGroup } from "./trx_maintenance_groups";
+import { TrxMaintenance } from "./trx_maintenances";
 
 @Entity("trx_maintenance_slas", { schema: "trx" })
 export class TrxMaintenanceSla {
 	@PrimaryGeneratedColumn("uuid")
 	id: string;
 
-	@ManyToOne(() => TrxMaintenanceGroup, { onDelete: "NO ACTION" })
+	@ManyToOne(() => TrxMaintenance, { onDelete: "NO ACTION" })
 	@JoinColumn()
-	maintenance_group: TrxMaintenanceGroup;
+	maintenance: TrxMaintenance;
 
 	@Column({
 		length: 256,
diff --git a/src/entity/trx_maintenances.ts b/src/entity/trx_maintenances.ts
index 620b5ca..dd83d4b 100644
--- a/src/entity/trx_maintenances.ts
+++ b/src/entity/trx_maintenances.ts
@@ -1,4 +1,4 @@
-import { Column, CreateDateColumn, DeleteDateColumn, Entity, JoinTable, ManyToOne, PrimaryGeneratedColumn, UpdateDateColumn } from "typeorm";
+import { Column, CreateDateColumn, DeleteDateColumn, Entity, JoinTable, ManyToOne, OneToMany, PrimaryGeneratedColumn, UpdateDateColumn } from "typeorm";
 import { TrxMaintenancePosition, TrxMaintenanceRemark, TrxMaintenanceStatus, TrxMaintenanceType } from "../types/trx";
 import { TrxCustomer } from "./trx_customers";
 import { TrxMaintenanceGroup } from "./trx_maintenance_groups";
@@ -15,9 +15,8 @@ export class TrxMaintenance {
 	})
 	code: string;
 
-	@ManyToOne(() => TrxMaintenanceGroup, { onDelete: "NO ACTION" })
-	@JoinTable()
-	maintenance_group: TrxMaintenanceGroup;
+	@OneToMany(() => TrxMaintenanceGroup, (mg) => mg.maintenance)
+	maintenance_groups: TrxMaintenanceGroup[];
 
 	@ManyToOne(() => TrxCustomer, { onDelete: "RESTRICT" })
 	@JoinTable()