Question

You have been given a univerity business plan that produced the
following information:
    PERSON: lname, fname, rname, idnum, private, linkblue
        lname, fname, rname are variable length strings
        idnum is type INT and is a key attribute
        private is BOOLEAN
        linkblue is string of 8 characters 

    ADDR:  idnum, adtype, streetaddr, city, state, country, zip
        idnum is a foreign key to PERSON.idnum
        adtype is a string in the set {"bill","permanent","local"}
        streetaddr is a variable length string that includes #, 
            street, and maybe apt #
        state is a 2 letter char denoting the state
        country is a 2 letter char denoting country
        zip is string no bigger than 10 characters.

    ADVISOR: student, advisor
        student is a foreign key to PERSON.idnum
        advisor is a foreign key to PERSON.idnum

    DIGITAL: smtype, idnum, smaddr
        smtype is a string in the set {"email", "facebook", "twitter"}
        idnum is a foreign key to PERSON.idnum
        smaddr is a variable length string

        There is a primary key on the pair (smtype, idnum)

    BILLING: idnum, txnum, postdate, amount, paid
        idnum is a foreign key to PERSON.idnum
        txnum is an INT and a key attribute, this is the transaction #
        postdate is type DATE and is the date the bill was posted
        amount is a DECIMAL(10,2) and is not null
        paid is boolean, true=paid, false=unpaid

#2 Write the DDL statement to alter the DIGITAL table to make both
   smtype and smaddr not allowed to be NULL.

The question is in bold.

Answer 1

Please find the SQL Query below.

QUERY

ALTER TABLE DIGITAL MODIFY COLUMN smtype VARCHAR2(20) NOT NULL;

ALTER TABLE DIGITAL MODIFY COLUMN smaddr VARCHAR2(100) NOT NULL;