MxiDev's questions

I am trying to implement code in Prolog that will split a list into two parts. Basically, if it is of even length the result is trivial, since the halves are the same size. But for the odd case the left part must contain one more element than the one on the right. It is explained with the following example:

?- div([1,2,3,4,5],X,Y). %Largo impar
X = [1,2,3]
Y = [4,5]

The implementation I thought of, watching some videos and tutorials, was the following:

div(L, A, B) :-
    append(A, B, L),
    length(A, N),
    length(B, N).

div(L, A, B) :-
    append(A, B, L),
    length(A, N),
    N1 is N + 1,
    length(B, N1).

However, for cases where the list is of odd length, it returns:

?- div([1,2,3,4,5],X,Y).
X = [1,2]
Y = [3,4,5]

I don't know what I may be missing to organize the elements well in the odd length lists. I hope someone can guide me.

I am trying to create a table in my database to simulate an application. The issue is that it throws me the error

ORA-00907: missing right parenthesis

and I don't know why it occurs (it clearly mentions the right parenthesis, but according to me it is said parenthesis). What I want to achieve is that the id_game attribute is automatically incremented. I tell you that I am working on Oracle 18c XE. I present the code below:

CREATE TABLE BIBLIOTECA(
        id_game INTEGER PRIMARY KEY DEFAULT nextval('serial'),
        rank INTEGER NOT NULL,
        name VARCHAR(64) NOT NULL
    );