DATASET( row )

This form is only used in an expression context. It allows you to in-line a single record dataset.

Example:

//the following examples demonstrate 4 ways to do the same thing:
personRecord := RECORD
  STRING20 surname;
  STRING10 forename;
  INTEGER2 age := 25;
END;
         
namesRecord := RECORD
  UNSIGNED     id;
  personRecord;
END;
          
namesTable := DATASET('~LR::TestRow',namesRecord,THOR);
//simple dataset file declaration form
         
addressRecord := RECORD
  UNSIGNED         id;
  DATASET(personRecord) people;   //child dataset form
  STRING40       street;
  STRING40       town;
  STRING2        st;
END;
         
personRecord tc0(namesRecord L) := TRANSFORM
  SELF := L;
END;
 
//** 1st way - using in-line dataset form in an expression  context
addressRecord t0(namesRecord L) := TRANSFORM
  SELF.people := PROJECT(DATASET([{L.id,L.surname,L.forename,L.age}],
                                 namesRecord),
                         tc0(LEFT));
  SELF.id := L.id;
  SELF := [];
END;
 
p0 := PROJECT(namesTable, t0(LEFT));
OUTPUT(p0);
 
//** 2nd way - using single-row dataset form
addressRecord t1(namesRecord L) := TRANSFORM
  SELF.people := PROJECT(DATASET(L), tc0(LEFT));
  SELF.id := L.id;
  SELF := [];
END;

p1 := PROJECT(namesTable, t1(LEFT));
OUTPUT(p1);

//** 3rd way - using single-row dataset form and ROW function
addressRecord t2(namesRecord L) := TRANSFORM
  SELF.people := DATASET(ROW(L,personRecord));
  SELF.id := L.id;
  SELF := [];
END;

p2 := PROJECT(namesTable, t2(LEFT));
OUTPUT(p2);

//** 4th way - using in-line dataset form in an expression context
addressRecord t4(namesRecord l) := TRANSFORM
  SELF.people := PROJECT(DATASET([L], namesRecord), tc0(LEFT));
  SELF.id := L.id;
  SELF := [];
END;
p3 := PROJECT(namesTable, t4(LEFT));
OUTPUT(p3);