diff --git a/src/models/entities/DistanceDonation.ts b/src/models/entities/DistanceDonation.ts
index a9b323e..848fba3 100644
--- a/src/models/entities/DistanceDonation.ts
+++ b/src/models/entities/DistanceDonation.ts
@@ -1,5 +1,5 @@
 import { IsInt, IsNotEmpty, IsPositive } from "class-validator";
-import { ChildEntity, Column, ManyToOne } from "typeorm";
+import { ChildEntity, Column, Index, ManyToOne } from "typeorm";
 import { ResponseDistanceDonation } from '../responses/ResponseDistanceDonation';
 import { Donation } from "./Donation";
 import { Runner } from "./Runner";
@@ -7,8 +7,9 @@ import { Runner } from "./Runner";
 /**
  * Defines the DistanceDonation entity.
  * For distanceDonations a donor pledges to donate a certain amount for each kilometer ran by a runner.
-*/
+ */
 @ChildEntity()
+@Index(['runner'])
 export class DistanceDonation extends Donation {
   /**
    * The donation's associated runner.
diff --git a/src/models/entities/Donation.ts b/src/models/entities/Donation.ts
index 363252d..f09cfa1 100644
--- a/src/models/entities/Donation.ts
+++ b/src/models/entities/Donation.ts
@@ -2,7 +2,7 @@ import {
   IsInt,
   IsPositive
 } from "class-validator";
-import { BeforeInsert, BeforeUpdate, Column, Entity, ManyToOne, PrimaryGeneratedColumn, TableInheritance } from "typeorm";
+import { BeforeInsert, BeforeUpdate, Column, Entity, Index, ManyToOne, PrimaryGeneratedColumn, TableInheritance } from "typeorm";
 import { ResponseDonation } from '../responses/ResponseDonation';
 import { Donor } from './Donor';
 
@@ -10,9 +10,10 @@ import { Donor } from './Donor';
  * Defines the Donation entity.
  * A donation just associates a donor with a donation amount.
  * The specifics of the amoun's determination has to be implemented in child classes.
-*/
+ */
 @Entity()
 @TableInheritance({ column: { name: "type", type: "varchar" } })
+@Index(['donor'])
 export abstract class Donation {
   /**
    * Autogenerated unique id (primary key).
diff --git a/src/models/entities/Participant.ts b/src/models/entities/Participant.ts
index 89fe4c2..6f4deea 100644
--- a/src/models/entities/Participant.ts
+++ b/src/models/entities/Participant.ts
@@ -9,18 +9,19 @@ import {
 
   IsString
 } from "class-validator";
-import { BeforeInsert, BeforeUpdate, Column, Entity, PrimaryGeneratedColumn, TableInheritance } from "typeorm";
+import { BeforeInsert, BeforeUpdate, Column, Entity, Index, PrimaryGeneratedColumn, TableInheritance } from "typeorm";
 import { config } from '../../config';
 import { ResponseParticipant } from '../responses/ResponseParticipant';
 import { Address } from "./Address";
 
-/**
- * Defines the Participant entity.
- * Participans can donate and therefor be associated with donation entities.
-*/
-@Entity()
-@TableInheritance({ column: { name: "type", type: "varchar" } })
-export abstract class Participant {
+/**
+ * Defines the Participant entity.
+ * Participans can donate and therefor be associated with donation entities.
+ */
+@Entity()
+@TableInheritance({ column: { name: "type", type: "varchar" } })
+@Index(['email'])
+export abstract class Participant {
   /**
    * Autogenerated unique id (primary key).
    */
diff --git a/src/models/entities/Runner.ts b/src/models/entities/Runner.ts
index 7b08593..0616006 100644
--- a/src/models/entities/Runner.ts
+++ b/src/models/entities/Runner.ts
@@ -1,5 +1,5 @@
 import { IsInt, IsNotEmpty, IsOptional, IsString } from "class-validator";
-import { ChildEntity, Column, ManyToOne, OneToMany } from "typeorm";
+import { ChildEntity, Column, Index, ManyToOne, OneToMany } from "typeorm";
 import { ResponseRunner } from '../responses/ResponseRunner';
 import { DistanceDonation } from "./DistanceDonation";
 import { Participant } from "./Participant";
@@ -11,8 +11,9 @@ import { Scan } from "./Scan";
  * Defines the runner entity.
  * Runners differ from participants in being able to actually accumulate a ran distance through scans.
  * Runner's get organized in groups.
-*/
+ */
 @ChildEntity()
+@Index(['group'])
 export class Runner extends Participant {
   /**
    * The runner's associated group.
diff --git a/src/models/entities/RunnerCard.ts b/src/models/entities/RunnerCard.ts
index 93aeecd..e4adc1a 100644
--- a/src/models/entities/RunnerCard.ts
+++ b/src/models/entities/RunnerCard.ts
@@ -6,7 +6,7 @@ import {
   IsOptional,
   IsPositive
 } from "class-validator";
-import { BeforeInsert, BeforeUpdate, Column, Entity, ManyToOne, OneToMany, PrimaryGeneratedColumn } from "typeorm";
+import { BeforeInsert, BeforeUpdate, Column, Entity, Index, ManyToOne, OneToMany, PrimaryGeneratedColumn } from "typeorm";
 import { RunnerCardIdOutOfRangeError } from '../../errors/RunnerCardErrors';
 import { ResponseRunnerCard } from '../responses/ResponseRunnerCard';
 import { Runner } from "./Runner";
@@ -16,8 +16,10 @@ import { TrackScan } from "./TrackScan";
  * Defines the RunnerCard entity.
  * A runnerCard is a physical representation for a runner.
  * It can be associated with a runner to create scans via the scan station's.
-*/
+ */
 @Entity()
+@Index(['runner'])
+@Index(['enabled'])
 export class RunnerCard {
   /**
    * Autogenerated unique id (primary key).
diff --git a/src/models/entities/RunnerTeam.ts b/src/models/entities/RunnerTeam.ts
index b8e224e..db9624e 100644
--- a/src/models/entities/RunnerTeam.ts
+++ b/src/models/entities/RunnerTeam.ts
@@ -1,5 +1,5 @@
 import { IsNotEmpty } from "class-validator";
-import { ChildEntity, ManyToOne } from "typeorm";
+import { ChildEntity, Index, ManyToOne } from "typeorm";
 import { ResponseRunnerTeam } from '../responses/ResponseRunnerTeam';
 import { RunnerGroup } from "./RunnerGroup";
 import { RunnerOrganization } from "./RunnerOrganization";
@@ -7,8 +7,9 @@ import { RunnerOrganization } from "./RunnerOrganization";
 /**
  * Defines the RunnerTeam entity.
  * This usually is a school class or department in a company.
-*/
+ */
 @ChildEntity()
+@Index(['parentGroup'])
 export class RunnerTeam extends RunnerGroup {
 
   /**
diff --git a/src/models/entities/Scan.ts b/src/models/entities/Scan.ts
index 3c53585..0a92bad 100644
--- a/src/models/entities/Scan.ts
+++ b/src/models/entities/Scan.ts
@@ -5,16 +5,19 @@ import {
 
   IsPositive
 } from "class-validator";
-import { BeforeInsert, BeforeUpdate, Column, Entity, ManyToOne, PrimaryGeneratedColumn, TableInheritance } from "typeorm";
+import { BeforeInsert, BeforeUpdate, Column, Entity, Index, ManyToOne, PrimaryGeneratedColumn, TableInheritance } from "typeorm";
 import { ResponseScan } from '../responses/ResponseScan';
 import { Runner } from "./Runner";
 
 /**
  * Defines the Scan entity.
  * A scan basicly adds a certain distance to a runner's total ran distance.
-*/
+ */
 @Entity()
 @TableInheritance({ column: { name: "type", type: "varchar" } })
+@Index(['runner'])
+@Index(['runner', 'created_at'])
+@Index(['valid'])
 export class Scan {
   /**
    * Autogenerated unique id (primary key).
diff --git a/src/models/entities/ScanStation.ts b/src/models/entities/ScanStation.ts
index 49ae740..db23220 100644
--- a/src/models/entities/ScanStation.ts
+++ b/src/models/entities/ScanStation.ts
@@ -6,7 +6,7 @@ import {
   IsPositive,
   IsString
 } from "class-validator";
-import { BeforeInsert, BeforeUpdate, Column, Entity, ManyToOne, OneToMany, PrimaryGeneratedColumn } from "typeorm";
+import { BeforeInsert, BeforeUpdate, Column, Entity, Index, ManyToOne, OneToMany, PrimaryGeneratedColumn } from "typeorm";
 import { ResponseScanStation } from '../responses/ResponseScanStation';
 import { Track } from "./Track";
 import { TrackScan } from "./TrackScan";
@@ -14,8 +14,11 @@ import { TrackScan } from "./TrackScan";
 /**
  * Defines the ScanStation entity.
  * ScanStations get used to create TrackScans for runners based on a scan of their runnerCard.
-*/
+ */
 @Entity()
+@Index(['track'])
+@Index(['prefix'])
+@Index(['enabled'])
 export class ScanStation {
   /**
    * Autogenerated unique id (primary key).
diff --git a/src/models/entities/TrackScan.ts b/src/models/entities/TrackScan.ts
index 17983f3..e6af00a 100644
--- a/src/models/entities/TrackScan.ts
+++ b/src/models/entities/TrackScan.ts
@@ -6,7 +6,7 @@ import {
 
   IsPositive
 } from "class-validator";
-import { ChildEntity, Column, ManyToOne } from "typeorm";
+import { ChildEntity, Column, Index, ManyToOne } from "typeorm";
 import { ResponseTrackScan } from '../responses/ResponseTrackScan';
 import { RunnerCard } from "./RunnerCard";
 import { Scan } from "./Scan";
@@ -16,8 +16,13 @@ import { Track } from "./Track";
 /**
  * Defines the TrackScan entity.
  * A track scan usaually get's generated by a scan station.
-*/
+ */
 @ChildEntity()
+@Index(['track'])
+@Index(['card'])
+@Index(['station'])
+@Index(['timestamp'])
+@Index(['station', 'timestamp'])
 export class TrackScan extends Scan {
   /**
    * The scan's associated track.
diff --git a/src/models/entities/User.ts b/src/models/entities/User.ts
index fc1b401..3408799 100644
--- a/src/models/entities/User.ts
+++ b/src/models/entities/User.ts
@@ -1,5 +1,5 @@
 import { IsBoolean, IsEmail, IsInt, IsNotEmpty, IsOptional, IsPhoneNumber, IsString, IsUrl, IsUUID } from "class-validator";
-import { ChildEntity, Column, JoinTable, ManyToMany, OneToMany } from "typeorm";
+import { ChildEntity, Column, Index, JoinTable, ManyToMany, OneToMany } from "typeorm";
 import { config } from '../../config';
 import { ResponsePrincipal } from '../responses/ResponsePrincipal';
 import { ResponseUser } from '../responses/ResponseUser';
@@ -8,12 +8,13 @@ import { Principal } from './Principal';
 import { UserAction } from './UserAction';
 import { UserGroup } from './UserGroup';
 
-/**
- * Defines the User entity.
- * Users are the ones that can use the "admin" webui and do stuff in the backend.
-*/
-@ChildEntity()
-export class User extends Principal {
+/**
+ * Defines the User entity.
+ * Users are the ones that can use the "admin" webui and do stuff in the backend.
+ */
+@ChildEntity()
+@Index(['enabled'])
+export class User extends Principal {
   /**
   * The user's uuid.
   * Mainly gets used as a per-user salt for the password hash.