Is there a datatype that allows me to store more than one item at a time

Question

Hello Everyone,
Is there a datatype that allows me to store more than one item at a time , in a column in a row?
I have to prepare a monthly account purchase system. Basically in this system a customer purchases items in an entire month as and when required on credit and then pays at the end of the month to clear the dues. So, i need to search the item from the inventory and then add it to the customer. So that when i want to see all the items purchased by a customer in the current month i get to see them. Later i calculate the bill and then ask him to pay and flushout old items which customer has purchased.
I am having great difficulty in preparing the database.
Please can anyone guide me! i have to finish this project in a weeks time.
Item Database:
SQL> desc items;
Name Null? Type
ITEMID VARCHAR2(10)
ITEMCODE VARCHAR2(10)
ITEMPRICE NUMBER(10)
ITEMQUAN NUMBER(10)
Customer Database:
SQL> desc customerdb;
Name Null? Type
CUSTID VARCHAR2(10)
CUSTFNAME VARCHAR2(20)
CUSTLNAME VARCHAR2(20)
CUSTMOBNO NUMBER(10)
CUSTADD VARCHAR2(20)
I need to store for every customer the items he has purchased in a month. But if i add a items purchased by a customer to the customer table entries look this.
SQL> select * from customerdb;
CUSTID CUSTFNAME CUSTLNAME CUSTMOBNO CUSTADD ITEM ITEMPRICE ITEMQUANTITY
123 abc xyz 9988556677 a1/8,hill dales soap 10 1
123 abc xyz 9988556677 " toothbrush 18 1
I can create a itempurchase table similar to above table without columns custfname,csutlnamecustmobno,custadd
ItemPurchaseTable :
CUSTID ITEM ITEMPRICE ITEMQUANTITY
123 soap 10 1
123 toothbrush 18 1
ill just have it as follows. But still the CUSTID FK from CustomerDB repeats for every row. I dont know how to solve this issue. Please can anyone help me.
I need to map 1 customer to the many items he has purchased in a month.
Edited by: Yukta Lolap on Oct 8, 2012 10:58 PM
Edited by: Yukta Lolap on Oct 8, 2012 11:00 PM

Answer 1

You must seriously read and learn about Normalization of tables; It improves your database design (at times may increase or decrease performance, subjective cases) and eases the Understanding efforts for a new person.
See the below tables and compare to the tables you have created
create table customers
  customer_id       number      primary key,
  fname             varchar2(50)  not null,
  mname             varchar2(50),
  lname             varchar2(50)  not null,
  join_date         date          default sysdate not null,
  is_active         char(1)     default 'N',
  constraint chk_active check (is_active in ('Y', 'N')) enable
create table customer_address
  address_id        number      primary key,
  customer_id       number      not null,
  line_1            varchar2(100)   not null,
  line_2            varchar2(100),
  line_3            varchar2(100),
  city              varchar2(100)   not null,
  state             varchar2(100)   not null,
  zip_code          number          not null,
  is_active         char(1)         default 'N' not null,
  constraint chk_add_active check (is_active in ('Y', 'N')),
  constraint fk_cust_id foreign key (customer_id) references customers(customer_id)
create table customer_contact
  contact_id        number      primary key,
  address_id        number      not null,
  area_code         number,
  landline          number,
  mobile            number,
  is_active         char(1)   default 'N' not null,
  constraint chk_cont_active check (is_active in ('Y', 'N'))
  constraint fk_add_id foreign key (address_id) references customer_address(address_id)
create table inventory
  inventory_id          number        primary key,
  item_code             varchar2(25)    not null,
  item_name             varchar2(100)   not null,
  item_price            number(8, 2)    default 0,
  item_quantity         number          default 0,
  constraint chk_item_quant check (item_quantity >= 0)
);You may have to improvise and adapt these tables according to your data and design to add or remove Columns/Constraints/Foreign Keys etc. I created them according to my understanding.
--Edit:- Added Purchases table and sample data;
create table purchases
  purchase_id           number        primary key,
  purchase_lot          number        unique key  not null,     --> Unique Key to map all the Purchases, at a time, for a customer
  customer_id           number        not null,
  item_code             number        not null,
  item_price            number(8,2)   not null,
  item_quantity         number        not null,
  discount              number(3,1)   default 0,
  purchase_date         date          default sysdate   not null,
  payment_mode          varchar2(20),
  constraint fk_cust_id foreign key (customer_id) references customers(customer_id)
insert into purchases values (1, 1001, 1, 'AZ123', 653, 10, 0, sysdate, 'Cash');
insert into purchases values (2, 1001, 1, 'AZ124', 225.5, 15, 2, sysdate, 'Cash');
insert into purchases values (3, 1001, 1, 'AZ125', 90, 20, 3.5, sysdate, 'Cash');
insert into purchases values (4, 1002, 2, 'AZ126', 111, 10, 0, sysdate, 'Cash');
insert into purchases values (5, 1002, 2, 'AZ127', 100, 10, 0, sysdate, 'Cash');
insert into purchases values (6, 1003, 1, 'AZ123', 101.25, 2, 0, sysdate, 'Cash');
insert into purchases values (7, 1003, 1, 'AZ121', 1000, 1, 0, sysdate, 'Cash');Edited by: Purvesh K on Oct 9, 2012 12:22 PM (Added Price Column and modified sample data.)