diff --git a/README.md b/README.md
index 6a46ead..682dd5f 100644
--- a/README.md
+++ b/README.md
@@ -4,14 +4,16 @@ Apollo server written in typescript that handles business logic.
 [![Build Status](https://travis-ci.com/fLotte-meets-HWR-DB/apollo-server.svg?token=YfRmpHAXqyUafCgSEexw&branch=main)](https://travis-ci.com/fLotte-meets-HWR-DB/apollo-server)
 
 ## Assumptions
-Userserver and postgres are running e.g. with Julius' Docker Compose.
+The [flotte-user-management server](https://github.com/fLotte-meets-HWR-DB/flotte-user-management) and postgres are running. Set the [environment variables](#Environment-Variables) accordingly.
 ## Usage
 ### Docker
+You can build and run a docker image with
 ```bash
 docker build -t <image name> .
-docker run --rm -p 4000:4000 <image name>
+docker run --rm -p 4000:4000 <image name> -e ...
 ```
-### Compile and run
+Don't forget to pass all the [environment variables](#Environment-Variables) with the -e option.
+### Compile and Run
 Install gulp if not installed
 ```bash
 npm -g gulp
@@ -21,25 +23,28 @@ npm install
 gulp
 npm start
 ```
+You can set the [environment variables](#Environment-Variables) in a _.env_ file.
 ### For Development
 Install node\_modules and gulp
 ```bash
 npm -g gulp
 npm install
 ```
-And start gulp in watch mode
+Start gulp in watch mode to recompile the type script
 ```bash
-gulp watch
+gulp watchTs
 ```
-This will watch *.ts files in _./src_ and recompile to _./dist_ and finally restart the server.
+This will watch *.ts files in _./src_ and recompile to _./dist_. You will have to restart the server yourself.
 
 ## Environment Variables
 The following environment variables can be used to configure the server:
 ```bash
 RPC_HOST=host:port
-NODE_ENV=development/porduction
+NODE_ENV=develop/production
 POSTGRES_CONNECTION_URL=postgres://username:password@host:port/database_name
 ```
-- __RPC_HOST__ is used for the connection with the userserver.
+- __RPC_HOST__ is used for the connection with the [flotte-user-management server](https://github.com/fLotte-meets-HWR-DB/flotte-user-management).
 - __NODE_ENV__ will not check authentication if set to development
 - __POSTGRES_CONNECTION_URL__ for connection with the postgres database
+
+If the API server cannot connect to the [flotte-user-management server](https://github.com/fLotte-meets-HWR-DB/flotte-user-management) or the postgres data base. It will try to reconnect in an endless loop.
diff --git a/src/datasources/db/lendingstationAPI.ts b/src/datasources/db/lendingstationAPI.ts
index a0f84c6..52c08ad 100644
--- a/src/datasources/db/lendingstationAPI.ts
+++ b/src/datasources/db/lendingstationAPI.ts
@@ -183,10 +183,7 @@ export class LendingStationAPI extends DataSource {
 
     async createTimeFrame (timeFrame: any) {
         return await this.connection.transaction(async (entityManager: EntityManager) => {
-            if (timeFrame.to === undefined) {
-                timeFrame.to = '';
-            }
-            timeFrame.dateRange = '[' + timeFrame.from + ',' + timeFrame.to + ')';
+            genDateRange(timeFrame);
             // checking for overlapping time frames
             const overlapping = await entityManager.getRepository(TimeFrame)
                 .createQueryBuilder('timeframe')
diff --git a/src/datasources/db/utils.ts b/src/datasources/db/utils.ts
index be8fbf1..7262417 100644
--- a/src/datasources/db/utils.ts
+++ b/src/datasources/db/utils.ts
@@ -23,45 +23,48 @@ import { ActionLog, Actions } from '../../model/ActionLog';
 import { UserInputError } from 'apollo-server-express';
 
 export function genDateRange (struct: any) {
-    if (struct.to === undefined) {
-        struct.to = '';
-    }
-    struct.dateRange = '[' + struct.from + ',' + struct.to + ')';
-    if (struct.from === undefined) {
+    if (!struct.dateRange || !struct.dateRange.from) {
         delete struct.dateRange;
+        return;
+    } else if (!struct.dateRange?.to) {
+        struct.dateRange.to = '';
+    } else if (struct.dateRange.to === struct.dateRange.from) {
+        throw new UserInputError('Date Range can not be empty, provide different dates.');
     }
-    // delete these keys, so the struct can be used to update the engagement entity
-    delete struct.from;
-    delete struct.to;
+    struct.dateRange = `[${struct.dateRange.from},${struct.dateRange.to})`;
 }
 
 /**
- * This function prepares the cargoBike struct, to be used in an update or create.
+ * This function helps prepare the cargoBike struct, to be used in an update or create.
  * It creates the numrange attributes than can be understood by postgres.
- * @param from
- * @param to
+ * @param range
  */
-function genNumRange (from: number, to: number) {
-    if (from === null || from === undefined) {
-        from = to;
-    } else if (to === null || to === undefined) {
-        to = from;
+function genNumRange (range: { min: number, max: number}) :string {
+    if (!range || (!range.max && !range.min)) {
+        return null;
+    } else if (range.min === null || range.min === undefined) {
+        range.min = range.max;
+    } else if (range.max === null || range.max === undefined) {
+        range.max = range.min;
     }
-    return from ? '[' + from + ',' + to + ']' : null;
+    if (range.min < 0) {
+        throw new UserInputError('Minimal value must be greater or equal to 0');
+    }
+    return `[${range.min},${range.max}]`;
 }
 
+/**
+ * This function prepares the cargoBike struct, to be used in an update or create.
+ * It creates the numrange attributes than can be understood by postgres.
+ * @param cargoBike
+ */
 export function genBoxDimensions (cargoBike: any) {
-    cargoBike.dimensionsAndLoad.boxLengthRange = genNumRange(cargoBike.dimensionsAndLoad.minBoxLength, cargoBike.dimensionsAndLoad.maxBoxLength);
-    cargoBike.dimensionsAndLoad.boxWidthRange = genNumRange(cargoBike.dimensionsAndLoad.minBoxWidth, cargoBike.dimensionsAndLoad.maxBoxWidth);
-    cargoBike.dimensionsAndLoad.boxHeightRange = genNumRange(cargoBike.dimensionsAndLoad.minBoxHeight, cargoBike.dimensionsAndLoad.maxBoxHeight);
-    // delete this so update cargo bike works
-    delete cargoBike.dimensionsAndLoad.minBoxLength;
-    delete cargoBike.dimensionsAndLoad.maxBoxLength;
-    delete cargoBike.dimensionsAndLoad.minBoxWidth;
-    delete cargoBike.dimensionsAndLoad.maxBoxWidth;
-    delete cargoBike.dimensionsAndLoad.minBoxHeight;
-    delete cargoBike.dimensionsAndLoad.maxBoxHeight;
+    if (!cargoBike.dimensionsAndLoad) { return; }
+    cargoBike.dimensionsAndLoad.boxLengthRange = genNumRange(cargoBike.dimensionsAndLoad.boxLengthRange);
+    cargoBike.dimensionsAndLoad.boxWidthRange = genNumRange(cargoBike.dimensionsAndLoad.boxWidthRange);
+    cargoBike.dimensionsAndLoad.boxHeightRange = genNumRange(cargoBike.dimensionsAndLoad.boxHeightRange);
 }
+
 /**
  * Can be used in resolvers to specify, if entry is locked by other user.
  * Returns true if locked by other user.
@@ -273,10 +276,10 @@ export class ActionLogger {
             // sometimes updates[value] is an array, e.g. timePeriods that are saved as a simple array in postgres
             if (updates[value] && typeof updates[value] === 'object' && !Array.isArray(updates[value])) {
                 Object.keys(updates[value]).forEach(subValue => {
-                    ret.push(alias + '."' + value + subValue[0].toUpperCase() + subValue.substr(1).toLowerCase() + '"');
+                    ret.push(`${alias}."${value}${subValue[0].toUpperCase()}${subValue.substr(1).toLowerCase()}"`);
                 });
             } else {
-                ret.push(alias + '."' + value + '"');
+                ret.push(`${alias}."${value}"`);
             }
         });
         return ret;
diff --git a/src/model/CargoBike.ts b/src/model/CargoBike.ts
index 4193a41..965651a 100644
--- a/src/model/CargoBike.ts
+++ b/src/model/CargoBike.ts
@@ -30,7 +30,6 @@ import {
     DeleteDateColumn
 } from 'typeorm';
 import { Provider } from './Provider';
-import { Participant } from './Participant';
 import { InsuranceData } from './InsuranceData';
 import { TimeFrame } from './TimeFrame';
 import { Taxes } from './Taxes';
@@ -90,13 +89,19 @@ export class Security {
     adfcCoding: string;
 }
 export class TechnicalEquipment {
-    @Column()
+    @Column({
+        nullable: true
+    })
     bicycleShift: string;
 
-    @Column()
+    @Column({
+        nullable: true
+    })
     isEBike: boolean;
 
-    @Column()
+    @Column({
+        nullable: true
+    })
     hasLightSystem: boolean;
 
     @Column({
@@ -106,10 +111,14 @@ export class TechnicalEquipment {
 }
 
 export class DimensionsAndLoad {
-    @Column()
+    @Column({
+        nullable: true
+    })
     hasCoverBox: boolean;
 
-    @Column()
+    @Column({
+        nullable: true
+    })
     lockable:boolean;
 
     @Column({
@@ -156,7 +165,7 @@ export class DimensionsAndLoad {
 
     @Column({
         nullable: true,
-        type: 'numrange'
+        type: 'decimal'
 
     })
     bikeWidth: number;
@@ -195,6 +204,11 @@ export class CargoBike implements Lockable {
     })
     name: string;
 
+    @Column({
+        nullable: true
+    })
+    state: string;
+
     @OneToMany(type => Equipment, equipment => equipment.cargoBikeId, {
         nullable: true,
         eager: true
diff --git a/src/model/ContactInformation.ts b/src/model/ContactInformation.ts
index 0e80f27..64e17aa 100644
--- a/src/model/ContactInformation.ts
+++ b/src/model/ContactInformation.ts
@@ -42,9 +42,7 @@ export class ContactInformation implements Lockable {
     })
     participantId: number;
 
-    @Column(type => {
-        return Address;
-    })
+    @Column(type => { return Address; })
     address: Address;
 
     @Column({
diff --git a/src/model/InsuranceData.ts b/src/model/InsuranceData.ts
index ef7c0fd..27fe256 100644
--- a/src/model/InsuranceData.ts
+++ b/src/model/InsuranceData.ts
@@ -20,22 +20,34 @@ This file is part of fLotte-API-Server.
 import { Column } from 'typeorm';
 
 export class InsuranceData {
-    @Column()
+    @Column({
+        nullable: true
+    })
     name: string;
 
-    @Column()
+    @Column({
+        nullable: true
+    })
     benefactor: string;
 
-    @Column()
+    @Column({
+        nullable: true
+    })
     billing: string;
 
-    @Column()
+    @Column({
+        nullable: true
+    })
     noPnP: string;
 
-    @Column()
+    @Column({
+        nullable: true
+    })
     maintenanceResponsible: string;
 
-    @Column()
+    @Column({
+        nullable: true
+    })
     maintenanceBenefactor: string;
 
     @Column({
diff --git a/src/model/Taxes.ts b/src/model/Taxes.ts
index 3c0f033..449cf27 100644
--- a/src/model/Taxes.ts
+++ b/src/model/Taxes.ts
@@ -25,7 +25,9 @@ export enum OrganisationArea {
     ZB = 'ZB'
 }
 export class Taxes {
-    @Column()
+    @Column({
+        nullable: true
+    })
     costCenter: string;
 
     @Column({
diff --git a/src/resolvers/cargoBikeResolver.ts b/src/resolvers/cargoBikeResolver.ts
index 502f181..b90b372 100644
--- a/src/resolvers/cargoBikeResolver.ts
+++ b/src/resolvers/cargoBikeResolver.ts
@@ -161,45 +161,12 @@ export default {
         isLockedByMe: (parent: any, __: any, { req }: { req: any }) => isLockedByMe(parent, { req }),
         isLocked: (parent: any, __: any, { req }: { req: any }) => isLocked(parent, { req })
     },
-    DimensionsAndLoad: {
-        minBoxLength: (parent: any) => {
-            if (!parent.boxLengthRange || parent.boxLengthRange === 'empty') {
-                return null;
-            }
-            return parent.boxLengthRange ? (parent.boxLengthRange as string).split(',')[0].replace('[', '') : null;
-        },
-        maxBoxLength: (parent: any) => {
-            if (!parent.boxLengthRange || parent.boxLengthRange === 'empty') {
-                return null;
-            }
-            const str = (parent.boxLengthRange as string).split(',')[1].replace(']', '');
-            return (str.length > 0) ? str : null;
-        },
-        minBoxWidth: (parent: any) => {
-            if (!parent.boxWidthRange || parent.boxWidthRange === 'empty') {
-                return null;
-            }
-            return parent.boxWidthRange ? (parent.boxWidthRange as string).split(',')[0].replace('[', '') : null;
+    NumRange: {
+        min: (parent: string) => {
+            return parent.replace(/^\[(.*),.*]$/, '$1');
         },
-        maxBoxWidth: (parent: any) => {
-            if (!parent.boxWidthRange || parent.boxWidthRange === 'empty') {
-                return null;
-            }
-            const str = (parent.boxWidthRange as string).split(',')[1].replace(']', '');
-            return (str.length > 0) ? str : null;
-        },
-        minBoxHeight: (parent: any) => {
-            if (!parent.boxHeightRange || parent.boxHeightRange === 'empty') {
-                return null;
-            }
-            return parent.boxHeightRange ? (parent.boxHeightRange as string).split(',')[0].replace('[', '') : null;
-        },
-        maxBoxHeight: (parent: any) => {
-            if (!parent.boxHeightRange || parent.boxHeightRange === 'empty') {
-                return null;
-            }
-            const str = (parent.boxHeightRange as string).split(',')[1].replace(']', '');
-            return (str.length > 0) ? str : null;
+        max: (parent: string) => {
+            return parent.replace(/^\[.*,(.*)]$/, '$1');
         }
     },
     Equipment: {
diff --git a/src/resolvers/lendingStationResolvers.ts b/src/resolvers/lendingStationResolvers.ts
index eb26f62..91d25bb 100644
--- a/src/resolvers/lendingStationResolvers.ts
+++ b/src/resolvers/lendingStationResolvers.ts
@@ -104,14 +104,15 @@ export default {
             return parent.loanTimes ? parent.loanTimes : [];
         }
     },
-    TimeFrame: {
-        from (parent: any) {
-            return (parent.dateRange as string).split(',')[0].replace('[', '');
-        },
-        to (parent: any) {
-            const str = (parent.dateRange as string).split(',')[1].replace(')', '');
-            return (str.length > 0) ? str : null;
+    DateRange: {
+        from (parent: string) {
+            return parent.replace(/^\[(.*),.*\)$/, '$1');
         },
+        to (parent: string) {
+            return parent.replace(/^\[.*,(.*)\)$/, '$1');
+        }
+    },
+    TimeFrame: {
         cargoBike (parent: any, __: any, { dataSources, req }: { dataSources: any, req: any }) {
             if (req.permissions.includes(Permission.ReadBike)) {
                 return dataSources.cargoBikeAPI.cargoBikeByTimeFrameId(parent.id);
diff --git a/src/schema/type-defs.ts b/src/schema/type-defs.ts
index d92729d..af19618 100644
--- a/src/schema/type-defs.ts
+++ b/src/schema/type-defs.ts
@@ -33,12 +33,14 @@ export default gql`
     The kind of currency depends on the database.
     """
     scalar Money
+    
     "The CargoBike type is central to the graph. You could call it the root."
     type CargoBike {
         id: ID!
         "see column A in info tabelle"
         group: Group
-        name: String
+        name: String!
+        state: BikeState
         modelName: String
         numberOfWheels: Int
         forCargo: Boolean
@@ -56,7 +58,7 @@ export default gql`
         """
         Does not refer to an extra table in the database.
         """
-        dimensionsAndLoad: DimensionsAndLoad!
+        dimensionsAndLoad: DimensionsAndLoad
         "If offset or limit is not provided, both values are ignored"
         bikeEvents(offset: Int, limit: Int): [BikeEvent]
         "If offset or limit is not provided, both values are ignored"
@@ -69,7 +71,7 @@ export default gql`
         provider: Provider
         "all participants currently engaged with the cargoBike"
         participants:  [Participant]
-        insuranceData: InsuranceData!
+        insuranceData: InsuranceData
         lendingStation: LendingStation
         taxes: Taxes
         currentEngagements: [Engagement]
@@ -83,6 +85,15 @@ export default gql`
         lockedUntil: Date
     }
 
+    """
+    Status of the CargoBike. More fields will be added, or removed.
+    """
+    enum BikeState {
+        ACTIVE
+        INACTIVE
+        INPREPARATION
+    }
+    
     """
     if you want to add bike to a lending station, create a new timeFrame with to: Date = null
     """
@@ -90,6 +101,7 @@ export default gql`
         "see column A in info tabelle"
         group: Group!
         name: String!
+        state: BikeState
         modelName: String!
         numberOfWheels: Int!
         forCargo: Boolean!
@@ -102,11 +114,11 @@ export default gql`
         """
         Does not refer to an extra table in the database.
         """
-        technicalEquipment: TechnicalEquipmentCreateInput!
+        technicalEquipment: TechnicalEquipmentCreateInput
         """
         Does not refer to an extra table in the database.
         """
-        dimensionsAndLoad: DimensionsAndLoadCreateInput!
+        dimensionsAndLoad: DimensionsAndLoadCreateInput
         """
         Refers to equipment that is not unique. See kommentierte info tabelle -> Fragen -> Frage 2
         When set to null or [], no relations will be added.
@@ -122,8 +134,8 @@ export default gql`
         stickerBikeNameState: StickerBikeNameState
         note: String
         providerId: ID
-        insuranceData: InsuranceDataCreateInput!
-        taxes: TaxesCreateInput!
+        insuranceData: InsuranceDataCreateInput
+        taxes: TaxesCreateInput
     }
 
     """
@@ -134,6 +146,7 @@ export default gql`
         "see column A in info tabelle"
         group: Group
         name: String
+        state: BikeState
         modelName: String
         numberOfWheels: Int
         forCargo: Boolean
@@ -180,15 +193,15 @@ export default gql`
         """
         Eventually, this field will become an enum or a separate data table and user can choose from a pool of insurance companies.
         """
-        name: String!
-        benefactor: String!
-        billing: String!
-        noPnP: String!
+        name: String
+        benefactor: String
+        billing: String
+        noPnP: String
         "eg. Anbieter, flotte, eigenleistung"
-        maintenanceResponsible: String!
-        maintenanceBenefactor: String!
+        maintenanceResponsible: String
+        maintenanceBenefactor: String
         maintenanceAgreement: String
-        hasFixedRate: Boolean!
+        hasFixedRate: Boolean
         fixedRate: Float
         """
         Projektzuschuss:
@@ -206,15 +219,15 @@ export default gql`
         """
         Eventually, this field will become an enum or a separate data table and user can choose from a pool of insurance companies.
         """
-        name: String!
-        benefactor: String!
-        billing: String!
-        noPnP: String!
+        name: String
+        benefactor: String
+        billing: String
+        noPnP: String
         "eg. Anbieter, flotte, eigenleistung"
-        maintenanceResponsible: String!
-        maintenanceBenefactor: String!
+        maintenanceResponsible: String
+        maintenanceBenefactor: String
         maintenanceAgreement: String
-        hasFixedRate: Boolean!
+        hasFixedRate: Boolean
         fixedRate: Float
         """
         Projektzuschuss:
@@ -254,17 +267,28 @@ export default gql`
         notes: String
     }
 
+    type NumRange {
+        min: Float
+        max: Float
+    }
+    
+    """
+    If min or max is omitted, the omitted value will be the same as the other given value
+    So if you pass one as null, both values with be over written with null.
+    """
+    input NumRangeInput {
+        min: Float
+        max: Float
+    }
+    
     "How are the dimensions and how much weight can handle a bike. This data is merged in the CargoBike table and the BikeModel table."
     type DimensionsAndLoad {
-        hasCoverBox: Boolean!
+        hasCoverBox: Boolean
         "cover box can be locked"
-        lockable: Boolean!
-        minBoxLength: Float
-        maxBoxLength: Float
-        minBoxWidth: Float
-        maxBoxWidth: Float
-        minBoxHeight: Float
-        maxBoxHeight: Float
+        lockable: Boolean
+        boxLengthRange: NumRange
+        boxWidthRange: NumRange
+        boxHeightRange: NumRange
         maxWeightBox: Float
         maxWeightLuggageRack: Float
         maxWeightTotal: Float
@@ -275,14 +299,11 @@ export default gql`
     }
 
     input DimensionsAndLoadCreateInput {
-        hasCoverBox: Boolean!
-        lockable: Boolean!
-        minBoxLength: Float
-        maxBoxLength: Float
-        minBoxWidth: Float
-        maxBoxWidth: Float
-        minBoxHeight: Float
-        maxBoxHeight: Float
+        hasCoverBox: Boolean
+        lockable: Boolean
+        boxLengthRange: NumRangeInput
+        boxWidthRange: NumRangeInput
+        boxHeightRange: NumRangeInput
         maxWeightBox: Float
         maxWeightLuggageRack: Float
         maxWeightTotal: Float
@@ -295,12 +316,9 @@ export default gql`
     input DimensionsAndLoadUpdateInput {
         hasCoverBox: Boolean
         lockable: Boolean
-        minBoxLength: Float
-        maxBoxLength: Float
-        minBoxWidth: Float
-        maxBoxWidth: Float
-        minBoxHeight: Float
-        maxBoxHeight: Float
+        boxLengthRange: NumRangeInput
+        boxWidthRange: NumRangeInput
+        boxHeightRange: NumRangeInput
         maxWeightBox: Float
         maxWeightLuggageRack: Float
         maxWeightTotal: Float
@@ -316,16 +334,16 @@ export default gql`
     So no id needed for mutation. One Mutation for the CargoBike will be enough.
     """
     type TechnicalEquipment {
-        bicycleShift: String!
-        isEBike: Boolean!
-        hasLightSystem: Boolean!
+        bicycleShift: String
+        isEBike: Boolean
+        hasLightSystem: Boolean
         specialFeatures: String
     }
 
     input TechnicalEquipmentCreateInput {
-        bicycleShift: String!
-        isEBike: Boolean!
-        hasLightSystem: Boolean!
+        bicycleShift: String
+        isEBike: Boolean
+        hasLightSystem: Boolean
         specialFeatures: String
     }
 
@@ -563,12 +581,12 @@ export default gql`
     }
 
     type Taxes {
-        costCenter: String!
+        costCenter: String
         organisationArea: OrganisationArea
     }
 
     input TaxesCreateInput {
-        costCenter: String!
+        costCenter: String
         organisationArea: OrganisationArea
     }
 
@@ -643,7 +661,7 @@ export default gql`
         keepLock: Boolean
     }
 
-    "An Event is a point in time, when the state of the bike somehow changed."
+    "An Event is a point in time concerning one cargo bike of an event type. For example a chain swap."
     type BikeEvent {
         id: ID!
         bikeEventType: BikeEventType!
@@ -923,13 +941,26 @@ export default gql`
         loanTimes: [String!]
     }
 
-    "(dt. Zeitscheibe) When was a bike where"
-    type TimeFrame {
-        id: ID!
-        "format YYYY-MM-dd"
+    type DateRange{
         from: Date!
+        "will be infinity of not omitted"
+        to: Date
+    }
+    
+    input DateRangeInput {
         "format YYYY-MM-dd"
+        from: Date!
+        """
+        format YYYY-MM-dd
+        will be infinity of not omitted
+        """
         to: Date
+    }
+    
+    "(dt. Zeitscheibe) When was a bike where"
+    type TimeFrame {
+        id: ID!
+        dateRange: DateRange!
         note: String
         lendingStation: LendingStation!
         cargoBike: CargoBike!
@@ -941,8 +972,7 @@ export default gql`
     }
 
     input TimeFrameCreateInput {
-        from: Date!
-        to: Date
+        dateRange: DateRangeInput!
         note: String
         lendingStationId: ID!
         cargoBikeId: ID!
@@ -950,8 +980,7 @@ export default gql`
 
     input TimeFrameUpdateInput {
         id: ID!
-        from: Date
-        to: Date
+        dateRange: DateRangeInput
         note: String
         lendingStationId: ID
         cargoBikeId: ID