PostgreSQL Error: relation "products" does not exist - sql

Question

I'm trying to create the following schema
While I execute the following code I get the relation "products" does not exist error.
CREATE TABLE Orders(
ORDERID serial NOT NULL PRIMARY KEY,
ORDERDATE text NOT NULL default'',
CUSTOMERID serial NOT NULL REFERENCES Customers(CUSTOMERID),
NETAMOUNT text NOT NULL default'',
TAX text NOT NULL default'',
TOTALAMOUNT text NOT NULL default''
);
CREATE TABLE Orderlines(
ORDERLINEID serial NOT NULL,
ORDERID serial NOT NULL REFERENCES Orders(ORDERID),
PROD_ID serial NOT NULL REFERENCES Products(PROD_ID),
QUANTITY text NOT NULL default'',
ORDERDATE text NOT NULL default'',
PRIMARY KEY(ORDERLINEID,ORDERID)
);
CREATE TABLE Products(
PROD_ID serial NOT NULL PRIMARY KEY,
CATEGORY text NOT NULL references Products(CATEGORY),
TITLE text NOT NULL default'',
ACTOR text NOT NULL default'',
PRICE text NOT NULL default''
);
I am doing this in http://sqlfiddle.com/ if it has anything to do with it.

Answer 1

When the table orderlines is created, the create table for the products table has not been executed. You need to add the foreign keys after all tables have been created.
You should only defined the primary key columns as serial, not the foreign key columns - they will be referencing the generated values from the target table. You don't want to generate a new value for the FK column when you insert.
The foreign key:
CATEGORY text NOT NULL references Products(CATEGORY)
is wrong because of two reasons: First because category is not the primary key of the products table. And secondly because it doesn't make sense that the category column references itself. You probably wanted to reference the categories table.
You script is also missing the customers table.
And you are choosing the wrong data types.
Number or dates should NEVER be stored in text (or varchar) columns.
Putting all that together, the script should be something like this:
create table customers
(
customerid serial primary key,
.... other columns
);
create table categories
(
category serial primary key,
categoryname text not null
);
CREATE TABLE Orders
(
ORDERID serial NOT NULL PRIMARY KEY,
ORDERDATE date NOT NULL, -- no text here!
CUSTOMERID integer NOT NULL, --- NO serial here!
NETAMOUNT decimal (22,4) NOT NULL, -- no text here!
TAX decimal(18,2) NOT NULL, -- no text here!
TOTALAMOUNT decimal (24,4) NOT NULL -- no text here!
);
CREATE TABLE Orderlines
(
ORDERLINEID serial NOT NULL,
ORDERID integer NOT NULL, -- NO serial here!
PROD_ID integer NOT NULL, -- NO serial here!
QUANTITY integer NOT NULL,
ORDERDATE date NOT NULL, -- NO text here!
PRIMARY KEY(ORDERLINEID,ORDERID)
);
CREATE TABLE Products
(
PROD_ID serial NOT NULL PRIMARY KEY,
CATEGORY integer NOT NULL references categories,
TITLE text NOT NULL,
ACTOR text NOT NULL,
PRICE decimal (18,2) NOT NULL
);
alter table orderlines add foreign key (orderid) REFERENCES Orders(ORDERID);
alter table orderlines add foreign key (prod_id) REFERENCES products(prod_id);
alter table orders add foreign key (customerid) REFERENCES Customers(CUSTOMERID);