drop table t1 cascade constraints
/

create table t1
 (id    number(15,0),
  tm    number(15,0),
  dt    date,
  value number(15,0))
/

create unique index t1_pk on t1(id)
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create unique index t1_uk on t1(tm)
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alter table t1 add constraint t1_pk primary key (id) using index
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alter table t1 add constraint t1_uk unique (tm)  using index
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alter table t1 add constraint t1_ck check (dt is not null)
/