i have a product table with a composite primary key and the composite primary key is working as excpected but whenever i try to use this composite primary key as a foreign key in another table , it dosent work
primary table product:
create table product
(
product_id number(4) ,
sub_product_id number(3) ,
category_id references category,
product_name varchar2(40),
product_brand varchar2(30),
price varchar2(15) ,
image_url varchar2(200) ,
color varchar2(30) ,
intmemory varchar2(30) ,
extmemory varchar2(30) ,
primary key(product_id,sub_product_id)
)
foreign key table cart :
create table cart
(
userid references register1 ,
product_id,
sub_product_id,
quantity number(3) ,
delivery_time varchar2(100) ,
foreign key(product_id ,sub_product_id) references product(product_id ,sub_product_id)
)
primary table is working fine but foreign keys are not working , they dont give error when i insert same (product_id , sub_product_id)
All I want is that the cart table dosen't have multiply entries of the same product_id, sub_product_id
As Jens mentioned, a foreign key is not the same as a unique key. You can create a unique key simply:
ALTER TABLE cart
ADD CONSTRAINT constraint_name
UNIQUE (product_id , sub_product_id);
Related
I have to write a query with the following criteria:
Write a query to list the title and artist of ONLY the items that have been ordered. Only list each title once.
Here are the CREATE tables that were made that cannot be changed.
CREATE TABLE artists
(
artist_id INT NOT NULL,
artist_name VARCHAR(30),
CONSTRAINT artist_pk PRIMARY KEY (artist_id)
);
CREATE TABLE items
(
item_id INT NOT NULL,
title VARCHAR(50) NOT NULL,
artist_id INT NOT NULL,
unit_price DECIMAL(9,2) NOT NULL,
CONSTRAINT items_pk PRIMARY KEY (item_id),
CONSTRAINT items_fk_artists
FOREIGN KEY (artist_id) REFERENCES artists (artist_id)
);
CREATE TABLE orders
(
order_id INT NOT NULL,
customer_id INT NOT NULL,
order_date DATE NOT NULL,
shipped_date DATE,
employee_id INT,
CONSTRAINT orders_pk PRIMARY KEY (order_id),
CONSTRAINT orders_fk_customers
FOREIGN KEY (customer_id) REFERENCES customers (customer_id),
CONSTRAINT orders_fk_employees
FOREIGN KEY (employee_id) REFERENCES employees (employee_id)
);
Here is what I have done for my script.
SELECT
items.title, artists.artist_name, orders.order_date
FROM
items
JOIN
orders
JOIN
artists;
Please let me know how I can consolidate.
You should say the structures of tables with respect to keys between tables.
I've been given the code below:
-- Create Customers table
CREATE TABLE Customers
(
cust_id char(10) NOT NULL ,
cust_name char(50) NOT NULL ,
cust_address char(50) NULL ,
cust_city char(50) NULL ,
cust_state char(5) NULL ,
cust_zip char(10) NULL ,
cust_country char(50) NULL ,
cust_contact char(50) NULL ,
cust_email char(255) NULL
);
-- Create OrderItems table
CREATE TABLE OrderItems
(
order_num int NOT NULL ,
order_item int NOT NULL ,
prod_id char(10) NOT NULL ,
quantity int NOT NULL ,
item_price decimal(8,2) NOT NULL
);
-- Create Orders table
CREATE TABLE Orders
(
order_num int NOT NULL ,
order_date datetime NOT NULL ,
cust_id char(10) NOT NULL
);
-- Create Products table
CREATE TABLE Products
(
prod_id char(10) NOT NULL ,
vend_id char(10) NOT NULL ,
prod_name char(255) NOT NULL ,
prod_price decimal(8,2) NOT NULL ,
prod_desc varchar(1000) NULL
);
-- Create Vendors table
CREATE TABLE Vendors
(
vend_id char(10) NOT NULL ,
vend_name char(50) NOT NULL ,
vend_address char(50) NULL ,
vend_city char(50) NULL ,
vend_state char(5) NULL ,
vend_zip char(10) NULL ,
vend_country char(50) NULL
);
-- Define primary keys
ALTER TABLE Customers WITH NOCHECK ADD CONSTRAINT PK_Customers PRIMARY KEY CLUSTERED (cust_id);
ALTER TABLE OrderItems WITH NOCHECK ADD CONSTRAINT PK_OrderItems PRIMARY KEY CLUSTERED (order_num, order_item);
ALTER TABLE Orders WITH NOCHECK ADD CONSTRAINT PK_Orders PRIMARY KEY CLUSTERED (order_num);
ALTER TABLE Products WITH NOCHECK ADD CONSTRAINT PK_Products PRIMARY KEY CLUSTERED (prod_id);
ALTER TABLE Vendors WITH NOCHECK ADD CONSTRAINT PK_Vendors PRIMARY KEY CLUSTERED (vend_id);
-- Define foreign keys
ALTER TABLE OrderItems ADD
CONSTRAINT FK_OrderItems_Orders FOREIGN KEY (order_num) REFERENCES Orders (order_num),
CONSTRAINT FK_OrderItems_Products FOREIGN KEY (prod_id) REFERENCES Products (prod_id);
ALTER TABLE Orders ADD
CONSTRAINT FK_Orders_Customers FOREIGN KEY (cust_id) REFERENCES Customers (cust_id);
ALTER TABLE Products ADD
CONSTRAINT FK_Products_Vendors FOREIGN KEY (vend_id) REFERENCES Vendors (vend_id);
I have a couple of questions:
What's the purpose of the Composite Key in table Orders?
Since order_num is a Primary Key as well as Foreign Key, I can't
understand how it can be Clustered in one table and
Non-Clustered in another.
Also, I don't understand the purpose of WITH NOCHECK when defining
the Primary Keys.
Thanks
What does order_item mean? From the look of things, you can remove it from the PK.
An FK basically says "the value here must be one of the values in that other table". Think of a dropdown box: the list of available choices is provided that the column in the REFERENCES ... (...) clause. CLUSTERED has no impact on it. You can make an FK references non-primary key column too.
When you create the primary key, SQL Server checks the table to ensure that the PK column contains no duplicate value. WITH NOCHECK disables check on existing data, but will check for any new data coming into the table. Its usage is not recommended.
create table customer(
custno number(10) constraint foo primary key,
custname character(15),
city character(15),
phone number(10));
create table invoice(
invo number(10) constraint inv primary key,
invdate date(10),
constarint c references customer(custno));
I cannot able to create the second table and am having doubt of the data type date and If I neglected that attribute(invdate) still I cannot able to create the second table.Reason please.
create table customer
( custno int constraint foo primary key
,custname character(15)
,city character(15)
,phone int
)
go
create table invoice
( invo int constraint inv primary key
constraint ck references customer(custno)
,invdate date
)
create table productinfotwo
(
productId number(10),
CONSTRAINT primary_pk Primary Key(productId),
productname varchar2(100),
SUBCATEGORYID number(10),
CONSTRAINT subcategory_fk Foreign Key(SUBCATEGORYID ) REFERENCES ProductSubCategory(SUBCATEGORYID ),
COMPANYID varchar2(20),
CONSTRAINT company_fk Foreign Key(COMPANYID ) References CompanyInfo(COMPANYID ),
price float,
quantity number(10),
description varchar2(1000),
);
You need to have them in order
Create ProductSubCategory table
Create CompanyInfo table
There is no datatype called float in Oracle. You can use NUMBER(4,2) instead
Remove the comma after description
The code should be
CREATE TABLE productinfotwo
(
productid NUMBER(10),
CONSTRAINT primary_pk PRIMARY KEY(productid),
productname VARCHAR2(100),
subcategoryid NUMBER(10),
CONSTRAINT subcategory_fk FOREIGN KEY(subcategoryid ) REFERENCES
productsubcategory(subcategoryid ),
companyid VARCHAR2(20),
CONSTRAINT company_fk FOREIGN KEY(companyid ) REFERENCES companyinfo(
companyid ),
price NUMBER(4, 2),
quantity NUMBER(10),
description VARCHAR2(1000)
);
I have Assignment due in which i'm stuck on a question.
Add a “Sales Detail” table to your database. This table is related to the Orders and Products tables. It shows the product and quantity ordered at least (add other fields if you wish but explain why you added them on your paper).
There is no description of this table on the diagram provided. Use your best database design skills here!
Create Table SalesDetail
(
SaleDetailID int,
ProductID char(5),
ManufactureID char(3) not null,
OrderNo int,
qtyOrdered int
PRIMARY
)
Alter Table SalesDetail
Add FOREIGN KEY (ProductID)
REFERENCES Products(ProductID)
My Error is I can not get it to link SalesDetail table to Products table.
Msg 1776, Level 16, State 0, Line 1
There are no primary or candidate keys in the referenced table 'Products' that match the referencing column list in the foreign key 'FK__SalesDeta__Produ__5EBF139D'.
Msg 1750, Level 16, State 0, Line 1
Could not create constraint. See previous errors.
Create Table Customers
(
CustomerNo char(4)
Constraint ck_CustomerNoHas4positionsWithNumbers
Check(CustomerNo like'[0-9],[0-9],[0-9],[0-9]'),
Company varchar(50) not null,
CustomerRep char(3),
CreditLimt money default(20000.00),
PRIMARY KEY(CustomerNo)
)
Create Table Salesreps
(
EmployeeNo char(3)
Constraint ck_EmployeeNoHasDigits check(EmployeeNo like'[0-9],[0-9],[0-9]'),
FirstName varchar(25) not null,
LastName varchar(25) not null,
Age int,
SalesRepOffice char(2) not null,
Title varchar(50),
HireDate Date not null,
Manager char(3) not null,
Quota money,
Sales money not null,
PRIMARY KEY(EmployeeNo)
)
Create Table Offices
(
Office char(2) Constraint ck_checkOfficeHasNumbersOnly check(Office like'[0-9],[0-9]'),
City varchar(25) not null,
Region varchar(10) not null,
Manager char(3) not null,
Target money,
Sales money not null
PRIMARY KEY(Office)
)
Create Table Orders
(
OrderNo int,
OrderDate Date not null,
CustomerNo char(4) not null,
SalesRep char(3) not null
PRIMARY KEY(OrderNo)
)
Create Table Products
(
ManufactureID char(3)
Constraint ck_ManufactureIDifItHasLettersOnly check(ManufactureID like'[a-z],[a-z],[a-z]'),
ProductID char(5)
Constraint ck_ProductIDhasTwoLettersAndThreeNumbers check(ProductID like'[0-9],[0-9],[a-z],[a-z],[a-z]'),
Description varchar(50) not null,
Price money not null,
QtyOnHand int not null,
PRIMARY KEY(ManufactureID, ProductID)
)
--Add Foreign Keys to all tables who needs them
Alter Table Customers
Add constraint fk_customerrep
FOREIGN KEY (CustomerRep)
REFERENCES Salesreps(EmployeeNo)
Alter Table Salesreps
Add constraint fk_salesrepoffice
FOREIGN KEY (SalesRepOffice)
REFERENCES Offices(Office),
constraint fk_manager
FOREIGN KEY (Manager)
REFERENCES Salesreps(EmployeeNo)
Alter Table Offices
Add constraint fk_officesmanger
FOREIGN KEY (Manager)
REFERENCES Salesreps(EmployeeNo)
Alter Table Orders
Add constraint fk_customerno
FOREIGN KEY (CustomerNo)
REFERENCES Customers(CustomerNo),
constraint fk_salesrep
FOREIGN KEY (SalesRep)
REFERENCES Salesreps(EmployeeNo)
The table Products has a composite key (ManufactureID, ProductID), so you cannot uniquely identify a product by just the ProductId. Therefore you have to create a composite foreign key that references to both ManufactureId and ProductID:
Alter Table SalesDetail
Add FOREIGN KEY (ManufactureId, ProductID)
REFERENCES Products(ManufactureID, ProductID)
ProductID is not a primary key like the error says. In your code
PRIMARY KEY(ManufactureID, ProductID)
This creates a primary key that both of those columns combined.
The primary key for Products is (ManufactureID, ProductID). So the SalesDetail table should contain both these columns, and both should be part of the foreign key constraint:
Alter Table SalesDetail
Add FOREIGN KEY (ManufactureID, ProductID)
REFERENCES Products(ManufactureID, ProductID)