Defining contracts/interfaces

In Denodo, an interface is a special type of view that consist only of a definition of fields and its data types. The most common usage is in a top-down design where you first define the fields and later associate the implementation(data) of the interface.

How to Create a New Interface

Follow these steps to create an interface view:

  1. Create a new folder under the tutorial database called "2 - data services".
  2. Right-click on this new folder and select New > Interface (or press Ctrl + Alt+ N).
  3. This will open the Interface view dialog. This dialog has three tabs, but we are only going to use the first one (Definition) to define your final view.
  4. Change the name of the interface view to: i_client_info.
  5. To add a new field to the interface, click the New field button. In the box to the right of the name of the new field, you can select the type of the field. Create the following structure:
    • client_id: text
    • full_name: text
    • client_type: text
    • full_address: text
    • phone: text
    • billing_due_date: localdate
    • balance: decimal

    To delete a field from the interface, select the check box beside the type of the field and click on Remove selected.

    TIP
  6. Finally click on (you will see a dialog warning "You have not set an implementation view for this interface. Queries that involve this interface view will fail.", but don't worry you will add it later in this tutorial.
  7. Press Ok to create the interface view!

By default, you can add fields with basic data types (int, float, text, etc.). If you want to select a compound field, select the Enable compound types check box.

NOTE

In the next section you will learn how to create Data Services using this interface.