Mapping unique constraints or alternate key - Please!

[Sebastião Carlos Santos <sc...@bol.com.br>]

  There are some days am studying OJB, with the main objective of using in a project that we will begin the development of here four weeks ago. In some tests that I accomplished, following the available material in the site, I didn't have great problems. However when coming across with the example below, I was in doubt as for the mapping of the table:

CREATE TABLE "TEST_TABLE" (
  "FIELD_A" NUMBER NOT NULL,
  "FIELD_B" NUMBER NOT NULL,
  "FIELD_C" VARCHAR2(128) NOT NULL,
  "FIELD_D" DATE NOT NULL,
  CONSTRAINT "TEST_TABLE_PK" PRIMARY KEY("FIELD_A"),
  CONSTRAINT "TEST_TABLE_UN01" UNIQUE("FIELD_B", "FIELD_C"),
  CONSTRAINT "TEST_TABLE_UN02" UNIQUE("FIELD_D"),
  CONSTRAINT "TEST_TABLE_CH01" CHECK(FIELD_A > 0),
  CONSTRAINT "TEST_TABLE_CH02" CHECK(FIELD_B > 0),
  CONSTRAINT "TEST_TABLE_CH03" CHECK(LENGTH(FIELD_C) > 64))

My great doubt in the present moment is as mapping the unique constraint. Could anybody feel an example?  
  
I advance gratitudes.