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Drop table cdvdtab;
Drop table booktab;
Drop table loantab;
Drop table itemtab;
Drop table copytab;
Drop table custab;
create table custab (customer_id integer primary key ,customer_name varchar(20),customer_sex varchar(10), customer_adress varchar(20),customer_rented_item varchar(20), customer_overdue_item varchar(10), customer_phone_No integer,customer_account_info varchar(10));
create table copytab (copy_id integer primary key,integer_of_copies integer, integer_of_rented_copies integer,integer_of_remaining_copy integer);
create table itemtab( item_id integer primary key,item_name varchar(20),item_purchase_date date,item_price varchar(10),item_loan_type integer,copy_id INTEGER REFERENCES copytab(copy_id) ON DELETE cascade);
create table booktab (Book_id integer primary key,book_name varchar(20),book_author_name varchar(20),book_published_year date)inherits(itemtab);create table cdvdtab (cdvd_id integer primary key,cdvd_name varchar(20),cdvd_manfc_name varchar(20),cdvd_release_year Date )inherits(itemtab);
create table loantab (loan_id integer primary key,loan_day integer,loan_date date,due_date date,return_date date,customer_id INTEGER REFERENCES custab(customer_id) ON DELETE cascade,item_id INTEGER REFERENCES itemtab(item_id) ON DELETE cascade);