과제

create table phoneInfo_basic (
        idx             number(6)       primary key,
        fr_name         varchar2(20)    not null,
        fr_phonenumber  varchar2(20)    not null,
        fr_email        varchar2(20)    default '-',
        fr_address      varchar2(20)    default '-',
        fr_regdate      DATE            default sysdate
);

create table phoneInfo_univ (
        idx             number(6)       primary key,
        fr_u_major      varchar2(20)    default 'N',
        fr_u_year       number(1)       check (5>=fr_u_year AND fr_u_year>=1),
        fr_ref          number(7)       references phoneinfo_basic(idx)
);


create table phoneinfo_com(
        idx             number(6)       primary key,
        fr_c_company    varchar2(20)    default 'N',
        fr_ref          number(6)       references phoneinfo_basic(idx)
);



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create table fr_type(
    friendty      varchar2(5)    unique
);

insert into fr_type values ('univ');
insert into fr_type values ('com');
insert into fr_type values ('cafe');


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create table phonebook(
    pidx            number(6)        primary key,
    friendtype      varchar2(5)      references fr_type(friendty)
);

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