ride db cannot publish

[xuyae573]

When I trigger BikeSharing.Services.Rides.Database project to publish, encounter below error,

Creating [EventsReferenceData]...
(87,1): SQL72014: .Net SqlClient Data Provider: Msg 102, Level 15, State 1, Line 1 Incorrect syntax near 'EXTERNAL'.
(87,0): SQL72045: Script execution error. The executed script:
CREATE EXTERNAL DATA SOURCE [EventsReferenceData]
WITH (
TYPE = RDBMS,
LOCATION = N'(localdb)\MSSQLLocalDB.database.windows.net',
DATABASE_NAME = N'bikesharing-services-events',
CREDENTIAL = [SQL_Credential]
);

An error occurred while the batch was being executed.