Unlike creating MySQL tables, to create tables of an SQLServer, PostgreSQL, or Oracle database, you need to specify the schema name and table name in table_mapping.
create external table person (
id int,
name varchar(1023),
age int
) tblproperties(
table_mapping = 'test_oracle.person'
);
Then, you can connect the Oracle client to Data Lake Analytics (DLA) to read data from the Oracle database.