Bug? BOOLEAN data type as PRIMARY KEY field

[Pranas]

Hello,

SAP DB 7.4 allows insert duplicate rows it to following table:

CREATE TABLE "DBA"."TABLE"
(
 "Charr"          CHAR(10)     ASCII NOT NULL,
  "Small"              Smallint     NOT NULL,
    "booll"             Boolean      NOT NULL DEFAULT TRUE,
...
 PRIMARY KEY (Charr,Small,booll),
...)

Regards,
Pranas