Explanation/Reference:
Explanation:
Box 1: Define general information
1. Start Microsoft SharePoint Designer 2013.
2. Click Open Site, and then enter the appropriate site name.
3. In the Navigation pane, under Site Objects, select External Content Types.
4. To open the External Content Type Designer, on the ribbon, click External Content Type.
5. On the New External Content Type page, do the following:
Next to Name, click New external content type, and then enter a unique name for the external

content type.7
Next to Display Name, enter a different name if you want a more descriptive display name.

Note: The external content type is a core concept of Business Connectivity Services (BCS). Used throughout the functionality and services offered by BCS, external content types are reusable metadata descriptions of connectivity information and data definitions plus the behaviors you want to apply to a certain category of external data.
Box 2: SharePoint designer does not support building ECT against Oracle.
You will either have to build the model by hand in Microsoft Visual Studio or use a third-party tool.
Reference: How to: Create external content types for SQL Server in SharePoint 2013