I am new to oracle 11g release 2 Please help

Question

When i run sql script in oracle 11g R 2 sql plus. It returns me with an error "missing right parenthesis" Error in last line. Simply its not accepting contraints in which i run them. Details as follows
Thankful for the help
create table courses (code varchar2(8) constraint S_PK primary key, description varchar2(30) constraint S_DESC_NN not null, category char(3) constraint C_CAT_NN not null, duration number(2) constraint C_DUR_NN not null, constraint C_CODE_CHK check (code = upper(code)), constraint C_CAT_CHK check (category in (`GEN', `BLD', `DSG')));
If i run above sql script, it says missing right parenthesis in the last line i.e * constraint C_CAT_CHK check (category in (`GEN', `BLD', `DSG')))
AGAIN:
create table courses (code varchar2(8) constraint S_PK primary key, description varchar2(30) constraint S_DESC_NN not null, category char(3) constraint C_CAT_NN not null, duration number(2) constraint C_DUR_NN not null);
Again If i run the above without checks, it gives the error of missing the right parenthesis in the last line i.e * constraint C_DUR_NN not null

Answer 1

Hi
it seems, quotes problem.
pl.try this
create table courses (code varchar2(8) constraint S_PK primary key, description varchar2(30) constraint S_DESC_NN not null,
category char(3) constraint C_CAT_NN not null,
duration number(2) constraint C_DUR_NN not null,
constraint C_CODE_CHK check (code = upper(code)),
constraint C_CAT_CHK check (category in ('GEN', 'BLD', 'DSG')));
-- DJ