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Implement Create Entity and Linking Entities in an MDK App

Create relationship between two OData entities.
You will learn
  • How to create relationship between parent and child entities
  • How to create a child entity to an existing parent entity
  • How to create a parent entity first and then a child entity
  • How to implement dynamic data subscription
jitendrakansalJitendra KansalJuly 8, 2022
Created by
jitendrakansal
August 5, 2019
Contributors
jitendrakansal
jitendrakansal
jitendrakansal

You may clone an existing project from GitHub repository to start with this tutorial.

For this tutorial, you will use Mobile Services sample backend (step 3) which has parent-child relationship setup among entities. For example, A customer can have n (>=0) number of sales orders.

To create an entity and then link it to another entity, you need to carry out the following tasks:

  • Create a new page for creating an order
  • Add an action bar item to the new page for cancelling the current activity
  • Create a new CreateRelatedEntity OData action to create a new sales order
  • Create a new message action for displaying failure message if order creation fails
  • Create a navigation action to show order creation page from Customer detail page
  • Implement data subscription to update count value when a new sales order is created
MDK
  • Step 1

    In this step, you will create the Create Order page as a Form Cell Page. This type of page allows for form input style changes. The page will provide only a subset of items available on the Customer Detail page. You will add the fields that will be editable by the end-user.

    1. Right-click the Pages folder | MDK: New Page | Form Cell Page | Next.

      MDK

      A Form Cell Page is suitable for pages that generate new objects or modify existing objects. It includes a form cell container by default. You can add form sections, multiple containers or action controls to this page. Under each container section, you can add various container items.

    2. Enter the Page Name SalesOrderHeaders_Create and click Next and the Finish on the Confirmation step.

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    3. In the Properties pane, set the Caption to Create Order.

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    4. Now, you will add the fields (like Currency Code, Net Amount, Tax Amount, Gross Amount, Life cycle status, Life cycle status name and order creation date) for creating a new sales order record by the end-user.

      In the Layout Editor, expand the Controls group. Drag and drop a Simple Property onto the Page area.

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    5. Drag and drop five additional Simple Property controls and one Date Picker control onto the page so you have seven total controls.

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    6. Select the first Simple Property control and provide the below information:

      Property Value
      NameFCCreateCurrencyCode
      Caption CurrencyCode
      ValueEUR
      MDK

      Under Value property, you can set some default values.

    7. Select the second Simple Property control and provide the below information:

      Property Value
      NameFCCreateNetAmount
      Caption NetAmount
      Value18.010
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    8. Select the third Simple Property control and provide the below information:

      Property Value
      NameFCCreateTaxAmount
      Caption TaxAmount
      Value108.010
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    9. Select the forth Simple Property control and provide the below information:

      Property Value
      NameFCCreateGrossAmount
      Caption GrossAmount
      Value126.02
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    10. Select the fifth Simple Property control and provide the below information:

      Property Value
      NameFCCreateLifeCycleStatus
      Caption LifeCycleStatus
      ValueN
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    11. Select the sixth Simple Property control and provide the below information:

      Property Value
      NameFCCreateLifeCycleStatusName
      Caption LifeCycleStatusName
      ValueNew
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    12. Select the last control Date Picker and provide the below information:

      Property Value
      NameFCCreatedate
      Caption Creation Date
      ModeSelect Datetime from the dropdown if not selected by default
      MDK
  • Step 2

    Now, you will add a button on the Create Order page and set its onPress to CloseModalPage_Cancel.action.

    1. Drag and drop an Action Bar Item to the upper left corner of the action bar.

      Action Bar Item is a button that users can use to fire actions when pressed. You can add an Action Bar Item only to the Action Bar (at the top of the page).

      MDK
    2. In the Properties pane, click the link icon to open the object browser for the System Item property.

      Double click the Cancel type and click OK.

      MDK

      System Item are predefined system-supplied icon or text. Overwrites Text and Icon if specified.

    3. Now, you will set the onPress event to CloseModalPage_Cancel.action.

      In Events tab, click the 3 dots icon for the OnPress property to open the Object Browser.

      Double click the CloseModalPage_Cancel.action and click OK to set it as the OnPress Action.

      MDK
  • Step 3
    1. Now, create a navigation action that will open the SalesOrderHeaders_Create.page when executed.

      Right-click the Actions folder | MDK: New Action | choose MDK UI Actions in Category | click Navigation Action | Next.

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    2. Provide the below information:

      Property Value
      Action NameNavToSalesOrderHeaders_Create
      PageToOpen Select SalesOrderHeaders_Create.page from the dropdown
      ModalPageSelect true from the dropdown
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    3. Click Next and then Finish on the confirmation step.

  • Step 4

    You will add a toolbar item to the Customers_Detail.page called Create Order. You will link this button to the navigation action you just created. This event will open the SalesOrderHeaders_Create.page when the Add button is pressed by the end-user.

    1. In Customers_Detail.page, drag and drop a Toolbar Item to the lower left of the page.

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    2. In the Properties pane, set Caption to Create Order.

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    3. In the Properties pane, click the Events tab, click the 3 dots icon for the OnPress property to open the Object Browser.

      Double click the NavToSalesOrderHeaders_Create.action and click OK to set it as the OnPress Action.

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  • Step 5

    The next step is to store newly created record locally for an offline application or send the new record directly back to the backed for online applications. You will now create an action to map the changes received from the Create Order page to the corresponding field in the OData service. You will also show a failure message if the create action fails to save the changes.

    1. Define a failure message.

      Right-click the Actions folder | MDK: New Action | choose MDK Message Actions in Category | click Message Action | Next.

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      Provide the below information:

      Property Value
      Action NameCreateSalesOrderHeaderEntityFailureMessage
      Type Select Message from the dropdown
      Message Failed to Create Sales Order record
      Title Create Sales Order
      OKCaption OK
      OnOK --None--
      CancelCaption leave it blank
      OnCancel --None--
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      Click Next and then Finish on the Confirmation step.

    2. You will create the OData action to create a sales order entity.

      You can find more details about Create Related Entity Action.

      Right-click the Actions folder | MDK: New Action | choose MDK Data Actions in Category | click OData Action | Next.

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      In Operation and Service Selection step, provide the below information:

      Property Value
      Action NameSalesOrderHeaders_CreateEntity
      Type Select CreateRelatedEntity from the dropdown
      ServiceSelect SampleServiceV2.service from the dropdown
      EntitySet Select SalesOrderHeaders from the dropdown
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      CreateRelatedEntity action creates the new entity against the navigation property of an existing entity with which the relationship is to be established.

    3. Click Next.

    4. In Parent Link and Properties Selection step, provide the below information:

      Property Value
      ParentLinkLinkItem Reference
      Target EntitySet Select Customers from the dropdown
      ReadLinkclick link icon and double click readLink
      Property Select SalesOrders from the dropdown
      MDK

      In Mobile Services sample backend, click Metadata URL and you will find SalesOrders navigation property for Customers entity.

    5. Since in SalesOrderHeaders_Create.page, we have defined seven properties (Currency Code, Net Amount, Tax Amount, Gross Amount, Life Cycle Status, Life Cycle Status Name and Creation Date) to be added, now in Properties section, you will bind them to respective UI Controls.

      Check the CreatedAt property and click the link icon to open the object browser.

      Change the drop down in the object browser to Controls & ClientData, click the Current Page radio button.

      In the search box start typing the control name FCCreatedate. The list will filter down to show the matching values. Double click the Value (Value) entry under the FCCreatedate field and click OK to set binding.

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    6. Repeat the above step for remaining properties: CurrencyCode, GrossAmount, LifeCycleStatus, LifeCycleStatusName, NetAmount and TaxAmount.

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      Click Next and Finish on the confirmation screen. The action editor will open with the SalesOrderHeaders_CreateEntity.action loaded.

    7. Define Success and Failure actions for SalesOrderHeaders_CreateEntity.action.

      In the action editor for the new action, expand the Common Action Properties and provide the below information:

      Property Value
      Success Action Click the link icon and bind it to CloseModalPage_Complete.action
      Failure Action Click the link icon and bind it to CreateSalesOrderHeaderEntityFailureMessage.action

      When SalesOrderHeaders_CreateEntity.action gets executed successfully then CloseModalPage_Complete.action will be triggered or if SalesOrderHeaders_CreateEntity.action fails then CreateSalesOrderHeaderEntityFailureMessage.action will be triggered.

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    8. Now, that the SalesOrderHeaders_CreateEntity.action has been created, you will need to call this action when the end-user presses the Save button. You will add a Save button on the SalesOrderHeaders_Create.page and link it to the SalesOrderHeaders_CreateEntity.action.

      In SalesOrderHeaders_Create.page, drag and drop an Action Bar Item to the upper right corner of the action bar.

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      Click the link icon to open the object browser for the System Item property.

      Double click the Save type and click OK.

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      In the Properties pane | Events tab, click the 3 dots icon for the OnPress property to open the Object Browser, bind it to SalesOrderHeaders_CreateEntity.action.

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    What is the CustomerDetails property in CreateOrder action being referred to ?

  • Step 6

    In Customers_Detail.page you added total number of order counts for a given customer. When a new SalesOrder is created, this count doesn’t get updated automatically unless you navigate back and forth to this page.

    DataSubscriptions : it is a way to listen to data changes that when triggers should cause a UI element to redraw. If your control or section has a target, that target is automatically subscribed for data change events. Otherwise you can also explicitly subscribe to DataSubscriptions by specifying an entity set name or readLink in an array. You can find more details here.

    In Customers_Detail.page, select Customer Orders Object Table control. In Properties section, click + icon under Misc | DataSubscriptions and double click SalesOrderHeaders and click OK.

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  • Step 7

    Deploy the updated application to your MDK client.

    1. Right-click Application.app and select MDK: Deploy.

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    2. Select deploy target as Mobile & Cloud.

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      You should see success message for both deployments.

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      Alternatively, you can select MDK: Redeploy in the command palette (View menu>Find Command OR press Command+Shift+p on Mac OR press Ctrl+Shift+P on Windows machine), it will perform the last deployment.

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  • Step 8

    Make sure you are choosing the right device platform tab above.

    Once you complete this tutorial, you can continue with Level Up with the Mobile Development Kit mission.

    What are the various "Mode" options available in the MDK Date Picker control?

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