I want to create a calculated amount field in the sales table that will accept the total of the items related to this order, but I ran into a problem.
"subqueries cannot be used in the generated column expression."
Please tell me how you can do this, taking into account the fact that the architecture cannot be changed.
CREATE TABLE products (
id bigserial PRIMARY KEY,
name varchar(255) NOT NULL,
description varchar(255) NOT NULL,
price decimal NOT NULL
);
CREATE TABLE sales (
id bigserial PRIMARY KEY,
employee_id int NOT NULL,
created_at timestamp NOT NULL,
amount decimal GENERATED ALWAYS AS ( /* subqueris */ ) STORED
);
CREATE TABLE products_sales (
sales_id int NOT NULL,
product_id int NOT NULL,
PRIMARY KEY (sales_id, product_id)
);
Related
can have in this case foreign key duplicated value? Or better just have an index on column?
Here is my table structure:
CREATE TABLE customers(
id INT (10) NOT NULL,
name VARCHAR (50) NOT NULL,
city VARCHAR (50) NOT NULL
);
CREATE TABLE orders(
cus_id INT (10) NOT NULL ,
order_date DATETIME NOT NULL
);
CREATE TABLE products(
id INT (5) NOT NULL,
product_name VARCHAR(50) NOT NULL,
product_price INT(10) NOT NULL
);
But in orderitems table (Where I have stored the ordered products, the customer can have multiple products ordered so the foreign key value (cus_id) can be duplicated)
CREATE TABLE ordered_items(
id INT (10) NOT NULL,
cus_id INT (10) NOT NULL,
product_id INT(5) NOT NULL
);
ALTER TABLE customers ADD CONSTRAINT customer_id PRIMARY KEY ( id ) ;
ALTER TABLE orders ADD CONSTRAINT customers_id_fr FOREIGN KEY ( cus_id ) REFERENCES customers ( id );
ALTER TABLE ordered_items ADD CONSTRAINT ordered_items_fr FOREIGN KEY ( cus_id ) REFERENCES customers ( id );
EDIT:
Sorry the ordered_items table have a unique ID column as well.
Yes! you can have multiple value of cus_id inside ordered_items. however, your intention is better served if you replace cus_id by order_id from orders, Thus your relationship would sound like,
a **customer** can have multiple *orders*,
an **order** can have multiple *order items*,
and an **order item** can only have single *product*
your sql would look like this
CREATE TABLE customers(
id INT (10) NOT NULL,
name VARCHAR (50) NOT NULL,
city VARCHAR (50) NOT NULL
);
ALTER TABLE customers ADD CONSTRAINT customer_id PRIMARY KEY ( id ) ;
CREATE TABLE orders(
id INT (5) NOT NULL,
cus_id INT (10) NOT NULL ,
order_date DATETIME NOT NULL
);
ALTER TABLE orders ADD CONSTRAINT order_id PRIMARY KEY ( id ) ;
ALTER TABLE orders ADD CONSTRAINT customers_id_fr FOREIGN KEY ( cus_id ) REFERENCES customers ( id );
CREATE TABLE products(
id INT (5) NOT NULL,
product_name VARCHAR(50) NOT NULL,
product_price DOUBLE NOT NULL
);
ALTER TABLE products ADD CONSTRAINT product_id PRIMARY KEY ( id ) ;
CREATE TABLE ordered_items(
id INT (10) NOT NULL,
order_id INT (10) NOT NULL,
product_id INT(5) NOT NULL
);
ALTER TABLE ordered_items ADD CONSTRAINT ordrItm_id PRIMARY KEY ( id ) ;
ALTER TABLE ordered_items ADD CONSTRAINT ordrItm_order_frK FOREIGN KEY ( order_id ) REFERENCES orders ( id );
ALTER TABLE ordered_items ADD CONSTRAINT ordrItm_prd_frK FOREIGN KEY ( product_id) REFERENCES products ( id );
I try to create three tables by using website suport compiler any code but I have a problem in the table of the bill.
When I run it I get to error show me it is near in foreign key
These are codes of three tables
CREATE TABLE patient (
Patient Id (5) Primary key,
Name Varchar (20) Not null ,
Age Int Not null ,
Weight Int Not null ,
Gender Varchar (10) Not null,
Address Varchar (50) Not null ,
Disease Varchar (20) Not null
);
CREATE TABLE doctors (
DoctorId Varchar (5) Primary key,
Doctorname Varchar (15) Not null,
Dept Varchar (15) Not null
);
CREATE TABLE bill (
Bill_no Varchar (50) Primary key,
Patient_Id Varchar (5) Foreign key,,
doctor_charge Int Not null,
patient_type Varchar (10) null,
no_of_days Int null,
lab_charge Int null,
bill Int Not null
);
Patient Table
CREATE TABLE patient
(
patient_id VARCHAR (5) PRIMARY KEY,
name VARCHAR (20) NOT NULL,
age INT NOT NULL,
weight INT NOT NULL,
gender VARCHAR (10) NOT NULL,
address VARCHAR (50) NOT NULL,
disease VARCHAR (20) NOT NULL
);
Errors
No data type has been assigned in Patient id column (Patient Id (5)
Primary key)
Patient id column name contains spaces. You need to
enclose the column name in double quotes or replace space with something else
(ex: _). It's not recommended to use spaces.
A column name with space
CREATE TABLE tablename ("column name" datatype);
Doctors Table
CREATE TABLE doctors
(
doctorid VARCHAR (5) PRIMARY KEY,
doctorname VARCHAR (15) NOT NULL,
dept VARCHAR (15) NOT NULL
);
Bill Table
CREATE TABLE bill
(
bill_no VARCHAR (50) PRIMARY KEY,
patient_id VARCHAR (5),
doctor_charge INT NOT NULL,
patient_type VARCHAR (10) NULL,
no_of_days INT NULL,
lab_charge INT NULL,
bill INT NOT NULL,
FOREIGN KEY (patient_id) REFERENCES patient(patient_id)
);
Errors
The way you have assigned foreign key is wrong. Please refer this and this article for more information. (Patient_Id Varchar (5) Foreign key,,)
There are two commans in the Patient_Id column (Patient_Id Varchar (5) Foreign key,,)
You have to provide reference of the table for which you want to use the reference key.
For example, you have table Persons which has Primary key PersonID, in that case if you want to use that as foreign key in another table, lets say Orders.
In Oracle
CREATE TABLE Orders (
OrderID numeric(10) not null,
OrderNumber numeric(10) not null,
PersonID numeric(10) not null,
CONSTRAINT fk_person_id
FOREIGN KEY (PersonID )
REFERENCES Persons(PersonID )
Your Case :
CREATE TABLE bill
( Bill_no Varchar (50) Primary key,
Patient_Id Varchar (5),
doctor_charge Int Not null,
patient_type Varchar (10) null,
no_of_days Int null,
lab_charge Int null,
bill Int Not null,
CONSTRAINT fk_patient_id
FOREIGN KEY (Patient_Id)
REFERENCES patient(Patient_Id)
);
Remove the 'Foreign Key' from the table creation script.
Add this to your SQL script:
ALTER TABLE [Bill] WITH CHECK ADD CONSTRAINT [FK_Bill_Patient] FOREIGN KEY([Patient_Id])
REFERENCES [Patient] ([Patient_Id])
GO
ALTER TABLE [Bill] CHECK CONSTRAINT [FK_Bill_Patient]
GO
The words FOREIGN KEY are only needed for introducing the name of the FK constraint. Since your other constraints are not named, you might as well skip that part and go straight to REFERENCES.
If you specify a foreign key constraint as part of the column definition, you can omit the datatype to allow it to inherit from its parent at the time of creation, which I think is good practice as the types will automatically match.
We use VARCHAR2 in Oracle, not VARCHAR.
You don't need to specify NULL for columns that are allowed to be null.
I am not sure a 5-character string is a good datatype for a unique ID. How will you generate the values? Normally an auto-incrementing sequence number simplifies this.
create table doctors
( doctorid varchar2(5) primary key
, doctorname varchar2(15) not null
, dept varchar2(15) not null );
create table patients
( patient_id varchar2(5) primary key
, name varchar2(20) not null
, age integer not null
, weight integer not null
, gender varchar2(10) not null
, address varchar2(50) not null
, disease varchar2(20) not null );
create table bills
( bill_no varchar2(50) primary key
, patient_id references patients -- Allow datatype to inherit from parent
, patient_type varchar2(10)
, no_of_days integer
, lab_charge integer
, bill integer not null );
I'm creating a database design for our water refilling system and I'm just new to databases. I am stuck with creating table that provides two different prices for a product. To further explain my problem, here's an example, a product's ('5 GALLON') price changes when it is delivered or bought on point by a customer. For example a delivered ('5 GALLON') is 45 pesos while a bought on point gallon is only 40 pesos. Can someone help me please?
Here's my codes so far
create table Product (
product_id int primary key,
prodtype_id int,
product_name varchar(55),
product_quantity int
)
-----NOT SURE IF THESE TWO TABLES ARE CORRECT
create table DeliveryPrice (
prod_id int,
product_price money,
foreign key (prod_id) references Product
)
create table OnPointPrice(
prod_id int,
product_price money,
foreign key (prod_id) references Product
)
You're likely better off just having the two prices in the Product table. They are attributes of the product, so that's where they belong.
Also, you should specify which columns are NOT NULL in your database (which should be most of them).
So is this correct?
create table Product(
product_id int primary key,
product_name varchar(55) not null,
product_quantity int not null,
pickup_price money not null,
delivery_price money not null
)
create table Customer(
customer_id int primary key,
customer_name varchar (255) not null,
customer_address varchar(200),
customer_phone int
)
create table INVOICE(
inv_number int primary key,
customer_id varchar(5),
foreign key (customer_id) references Customer,
inv_date date not null,
bought_mode char(10) not null
)
create table LINE(
INV_NUMBER int,
foreign key (INV_NUMBER) references INVOICE,
LINE_NUMBER INT not null,
PRIMARY KEY (INV_NUMBER, LINE_NUMBER),
line_quantity int not null,
line_price money not null
)
For some reason I'm getting an error* in my code. I'm quite new to PostgreSQL, and simply SQL. What is causing this error?
*there is no unique constraint matching given keys for referenced table "tech".
BEGIN;
CREATE TABLE Person (
person_id SERIAL PRIMARY KEY,
firstname VARCHAR(128),
lastname VARCHAR(128),
email_adr VARCHAR(128),
UNIQUE(person_id, email_adr)
);
CREATE TABLE Phone (
person_id INT REFERENCES Person(person_id),
phone_nr INT PRIMARY KEY,
UNIQUE(phone_nr)
);
CREATE TABLE Tech (
tech_id INT REFERENCES Person(person_id),
username VARCHAR(80) PRIMARY KEY,
password VARCHAR(80) NOT NULL,
location Varchar(128),
UNIQUE(username, tech_id)
);
CREATE TABLE Customer (
customer_id INT REFERENCES Persons(person_id),
addresse VARCHAR(255) NOT NULL,
UNIQUE(customer_id)
);
CREATE TABLE Task (
task_id SERIAL PRIMARY KEY,
payment MONEY,
tech INT REFERENCES Tech(tech_id) NOT NULL,
customer INT REFERENCES Customer(customer_id) NOT NULL,
start_date DATE NOT NULL,
end_dato DATE,
UNIQUE(tech, customer, start_date, end_date)
);
COMMIT;
In table Task you trying to reference to table Tech by tech_id. To do that you must add UNIQUE CONSTRAINT to tech_id in Tech.
Right now in table Tech you have UNIQUE(username, tech_id) that means that values in column tech_id could by doubled Ex.
Tech
-------------------------------
tech_id username, ....
------------------------------
1 'John'
2 'Tony'
1 'Nataly'
Acctually the better idea is to set reference by PRIMARY KEY, so in your case username in table Tech.
If you want to leave structure the way present in question, you should just add UNIQUE(tech_id) in column Tech.
What do you think of this code?
BEGIN;
CREATE TABLE Person (
person_id SERIAL PRIMARY KEY,
firstname VARCHAR(128),
lastname VARCHAR(128),
email_adr VARCHAR(128),
UNIQUE(person_id),
UNIQUE(email_adr)
);
CREATE TABLE Phone (
person_id INT,
phone_nr INT PRIMARY KEY,
);
CREATE TABLE Tech (
tech_id INT,
username VARCHAR(80) PRIMARY KEY,
password VARCHAR(80) NOT NULL,
location Varchar(128),
FOREIGN KEY(tech_id) REFERENCES Person(person_id),
UNIQUE(username),
UNIQUE(tech_id)
);
CREATE TABLE Customer (
customer_id INT REFERENCES Persons(person_id),
addresse VARCHAR(255) NOT NULL,
FOREIGN KEY(tech_id) REFERENCES Person(person_id),
UNIQUE(customer_id)
);
CREATE TABLE Task (
task_id SERIAL PRIMARY KEY,
payment MONEY,
tech varchar(80) REFERENCES Tech(username) NOT NULL,
customer INT REFERENCES Customer(customer_id) NOT NULL,
start_date DATE NOT NULL,
end_dato DATE,
UNIQUE(tech, customer, start_date, end_date)
);
COMMIT;
I have the following problem to solve in SQL :
d) A query that provides management information on take up of the various types of activities on offer. For each type of activity, the query should show the total number of individuals who took that type of activity and the average number of individuals taking each type of activity.
Here are my tables :
CREATE TABLE accommodations
(
chalet_number int PRIMARY KEY,
chalet_name varchar(40) NOT NULL,
no_it_sleeps number(2) NOT NULL,
indivppw number(4) NOT NULL
)
CREATE TABLE supervisors
(
supervisor_number int PRIMARY KEY,
supervisor_forename varchar(30) NOT NULL,
supervisor_surname varchar(30) NOT NULL,
mobile_number varchar(11) NOT NULL
)
CREATE TABLE visitors
(
visitor_ID int PRIMARY KEY,
group_ID int NOT NULL,
forename varchar(20) NOT NULL,
surname varchar(20) NOT NULL,
dob date NOT NULL,
gender varchar(1) NOT NULL
)
CREATE TABLE activities
(
activity_code varchar(10) PRIMARY KEY,
activity_title varchar(20) NOT NULL,
"type" varchar(20) NOT NULL
)
CREATE TABLE "groups"
(
group_ID int PRIMARY KEY,
group_leader varchar(20) NOT NULL,
group_name varchar(30)
number_in_group number(2) NOT NULL
)
CREATE TABLE bookings
(
group_ID int NOT NULL,
start_date date NOT NULL,
chalet_number int NOT NULL,
no_in_chalet number(2) NOT NULL,
start_date date NOT NULL,
end_date date NOT NULL,
CONSTRAINT bookings_pk PRIMARY KEY(group_ID, chalet_number));
CREATE TABLE schedule
(
schedule_ID int PRIMARY KEY,
activity_code varchar(10) NOT NULL,
time_of_activity number(4,2) NOT NULL,
am_pm varchar(2) NOT NULL,
"date" date NOT NULL
)
CREATE TABLE activity_bookings
(
visitor_ID int NOT NULL,
schedule_ID int NOT NULL,
supervisor_number int NOT NULL,
comments varchar(200),
CONSTRAINT event_booking_pk PRIMARY KEY(visitor_ID, schedule_ID));
ALTER TABLE visitors
ADD FOREIGN KEY (group_ID)
REFERENCES "groups"(group_ID)
ALTER TABLE Schedule
ADD FOREIGN KEY (activity_code)
REFERENCES activities(activity_code)
ALTER TABLE bookings
ADD FOREIGN KEY (group_ID)
REFERENCES "groups"(group_ID)
ALTER TABLE bookings
ADD FOREIGN KEY (chalet_number)
REFERENCES accommodations(chalet_number)
ALTER TABLE activity_bookings
ADD FOREIGN KEY (visitor_ID)
REFERENCES visitors(visitor_ID)
ALTER TABLE activity_bookings
ADD FOREIGN KEY (schedule_ID)
REFERENCES schedule(schedule_ID)
ALTER TABLE activity_bookings
ADD FOREIGN KEY (supervisor_number)
REFERENCES supervisors(supervisor_number)
I have the following solution:
SELECT activities."type", 'overalltotal' AS OT, ('overalltotal' / 'activities') AS AVG
FROM activities, schedule
WHERE 'overalltotal' = (SELECT SUM(COUNT(schedule_ID))
FROM activities, schedule
WHERE schedule.activity_code = activities.activity_code
GROUP BY activities."type"
)
AND 'activities' = (SELECT COUNT(DISTINCT activities."type")
FROM activities
)
AND schedule.activity_code = activities.activity_code
GROUP BY activities."type";
I have implemented sample data and code to check the variables above:
SELECT SUM(COUNT(schedule_ID))
FROM activities, schedule
WHERE schedule.activity_code = activities.activity_code
GROUP BY activities."type";
Result : 20
SELECT COUNT(DISTINCT activities."type")
FROM activities;
Result : 5
However when running the code :
ORA-01722: invalid number
01722. 00000 - "invalid number"
*Cause:
*Action:
EDIT:
Using Dave's Code i have the following output:
Snowboarding 15
sledding 19
Snowmobiling 6
Ice Skating 5
Skiing 24
How would i do the final part of the question?
and the average number of individuals taking each type of activity.
You must use double quotes around column names in Oracle, not single quotes. For example, "overalltotal". Single quotes are for text strings, which is why you're getting an invalid number error.
EDIT: This is probably the type of query you want to use:
SELECT activities."type", COUNT(*) AS total, COUNT(*)/(COUNT(*) OVER ()) AS "avg"
FROM activities a
JOIN schedule s ON a.activity_code=s.activity_code
JOIN activity_bookings ab ON s.schedule_ID=ab.schedule_ID
GROUP BY activities."type";
Basically, because each activity booking has one visitor id, we want to get all the activity bookings for each activity. We have to go through schedule to do that. They we group the rows by the activity type and count how many activity bookings we have for each type.