PostgreSQL

Customer Order Example

S511

SLIS Postgresql server

• PHP PGAdmin– https://ella.slis.indiana.edu/adm/phppgadmin/– Get your username and password from SLIS IT

department

Create Schema

Create Schema

Create Table Schema

Create Tables

CUSTOMER order ORDERINFO1 M

has ORDERLINE1 M

ITEM

has

1

1

has

has

STOCK

BARCODE

1

1

M

M

Create Tablescreate table customer( customer_id serial , title char(4) , fname varchar(32) , lname varchar(32) not null, addressline varchar(64) , town varchar(32) , zipcode char(10) not null, phone varchar(16) , CONSTRAINT customer_pk PRIMARY KEY(customer_id));

Create Tablescreate table item( item_id serial , description varchar(64) not null, cost_price numeric(7,2) , sell_price numeric(7,2) , CONSTRAINT item_pk PRIMARY KEY(item_id));

create table orderinfo( orderinfo_id serial , customer_id integer not null, date_placed date not null, date_shipped date , shipping numeric(7,2) , CONSTRAINT orderinfo_pk PRIMARY KEY(orderinfo_id));

Create Tablescreate table stock( item_id integer not null, quantity integer not null, CONSTRAINT stock_pk PRIMARY KEY(item_id));

create table orderline( orderinfo_id integer not null, item_id integer not null, quantity integer not null, CONSTRAINT orderline_pk PRIMARY KEY(orderinfo_id, item_id));

create table barcode( barcode_ean char(13) not null, item_id integer not null, CONSTRAINT barcode_pk PRIMARY KEY(barcode_ean));

Insert values-- Customers

insert into customer(title, fname, lname, addressline, town, zipcode, phone) values('Miss','Jenny','Stones','27 Rowan Avenue','Hightown','NT2 1AQ','023 9876');insert into customer(title, fname, lname, addressline, town, zipcode, phone) values('Mr','Andrew','Stones','52 The Willows','Lowtown','LT5 7RA','876 3527');insert into customer(title, fname, lname, addressline, town, zipcode, phone) values('Miss','Alex','Matthew','4 The Street','Nicetown','NT2 2TX','010 4567');insert into customer(title, fname, lname, addressline, town, zipcode, phone) values('Mr','Adrian','Matthew','The Barn','Yuleville','YV67 2WR','487 3871');insert into customer(title, fname, lname, addressline, town, zipcode, phone) values('Mr','Simon','Cozens','7 Shady Lane','Oakenham','OA3 6QW','514 5926');insert into customer(title, fname, lname, addressline, town, zipcode, phone) values('Mr','Neil','Matthew','5 Pasture Lane','Nicetown','NT3 7RT','267 1232');insert into customer(title, fname, lname, addressline, town, zipcode, phone) values('Mr','Richard','Stones','34 Holly Way','Bingham','BG4 2WE','342 5982');insert into customer(title, fname, lname, addressline, town, zipcode, phone) values('Mrs','Ann','Stones','34 Holly Way','Bingham','BG4 2WE','342 5982');insert into customer(title, fname, lname, addressline, town, zipcode, phone) values('Mrs','Christine','Hickman','36 Queen Street','Histon','HT3 5EM','342 5432');insert into customer(title, fname, lname, addressline, town, zipcode, phone) values('Mr','Mike','Howard','86 Dysart Street','Tibsville','TB3 7FG','505 5482');insert into customer(title, fname, lname, addressline, town, zipcode, phone) values('Mr','Dave','Jones','54 Vale Rise','Bingham','BG3 8GD','342 8264');insert into customer(title, fname, lname, addressline, town, zipcode, phone) values('Mr','Richard','Neill','42 Thatched Way','Winnersby','WB3 6GQ','505 6482');insert into customer(title, fname, lname, addressline, town, zipcode, phone) values('Mrs','Laura','Hardy','73 Margarita Way','Oxbridge','OX2 3HX','821 2335');insert into customer(title, fname, lname, addressline, town, zipcode, phone) values('Mr','Bill','O\'Neill','2 Beamer Street','Welltown','WT3 8GM','435 1234');insert into customer(title, fname, lname, addressline, town, zipcode, phone) values('Mr','David','Hudson','4 The Square','Milltown','MT2 6RT','961 4526');

Insert values-- Items

insert into item(description, cost_price, sell_price) values('Wood Puzzle', 15.23, 21.95);insert into item(description, cost_price, sell_price) values('Rubik Cube', 7.45, 11.49);insert into item(description, cost_price, sell_price) values('Linux CD', 1.99, 2.49);insert into item(description, cost_price, sell_price) values('Tissues', 2.11, 3.99);insert into item(description, cost_price, sell_price) values('Picture Frame', 7.54, 9.95);insert into item(description, cost_price, sell_price) values('Fan Small', 9.23, 15.75);insert into item(description, cost_price, sell_price) values('Fan Large', 13.36, 19.95);insert into item(description, cost_price, sell_price) values('Toothbrush', 0.75, 1.45);insert into item(description, cost_price, sell_price) values('Roman Coin', 2.34, 2.45);insert into item(description, cost_price, sell_price) values('Carrier Bag', 0.01, 0.0);insert into item(description, cost_price, sell_price) values('Speakers', 19.73, 25.32);

Insert values-- Barcodes

insert into barcode(barcode_ean, item_id) values('6241527836173', 1);insert into barcode(barcode_ean, item_id) values('6241574635234', 2);insert into barcode(barcode_ean, item_id) values('6264537836173', 3);insert into barcode(barcode_ean, item_id) values('6241527746363', 3);insert into barcode(barcode_ean, item_id) values('7465743843764', 4);insert into barcode(barcode_ean, item_id) values('3453458677628', 5);insert into barcode(barcode_ean, item_id) values('6434564564544', 6);insert into barcode(barcode_ean, item_id) values('8476736836876', 7);insert into barcode(barcode_ean, item_id) values('6241234586487', 8);insert into barcode(barcode_ean, item_id) values('9473625532534', 8);insert into barcode(barcode_ean, item_id) values('9473627464543', 8);insert into barcode(barcode_ean, item_id) values('4587263646878', 9);insert into barcode(barcode_ean, item_id) values('9879879837489', 11);insert into barcode(barcode_ean, item_id) values('2239872376872', 11);

Insert values-- Stock

insert into stock(item_id, quantity) values(1,12);insert into stock(item_id, quantity) values(2,2);insert into stock(item_id, quantity) values(4,8);insert into stock(item_id, quantity) values(5,3);insert into stock(item_id, quantity) values(7,8);insert into stock(item_id, quantity) values(8,18);insert into stock(item_id, quantity) values(10,1);

-- Order info

insert into orderinfo(customer_id, date_placed, date_shipped, shipping) values(3,'03-13-2004','03-17-2004', 2.99);insert into orderinfo(customer_id, date_placed, date_shipped, shipping) values(8,'06-23-2004','06-24-2004', 0.00);insert into orderinfo(customer_id, date_placed, date_shipped, shipping) values(15,'09-02-2004','09-12-2004', 3.99);insert into orderinfo(customer_id, date_placed, date_shipped, shipping) values(13,'09-03-2004','09-10-2004', 2.99);insert into orderinfo(customer_id, date_placed, date_shipped, shipping) values(8,'07-21-2004','07-24-2004', 0.00);

Insert values-- Order line

insert into orderline(orderinfo_id, item_id, quantity) values(1, 4, 1);insert into orderline(orderinfo_id, item_id, quantity) values(1, 7, 1);insert into orderline(orderinfo_id, item_id, quantity) values(1, 9, 1);insert into orderline(orderinfo_id, item_id, quantity) values(2, 1, 1);insert into orderline(orderinfo_id, item_id, quantity) values(2, 10, 1);insert into orderline(orderinfo_id, item_id, quantity) values(2, 7, 2);insert into orderline(orderinfo_id, item_id, quantity) values(2, 4, 2);insert into orderline(orderinfo_id, item_id, quantity) values(3, 2, 1);insert into orderline(orderinfo_id, item_id, quantity) values(3, 1, 1);insert into orderline(orderinfo_id, item_id, quantity) values(4, 5, 2);insert into orderline(orderinfo_id, item_id, quantity) values(5, 1, 1);insert into orderline(orderinfo_id, item_id, quantity) values(5, 3, 1);

SQL Queries

• select town, lname AS "Last Name" from customer order by town DESC, lname ASC;

• select distinct town from customer;

• select description, cost_price*100 as "Cost Price" from item;

SQL Queries

• select title, fname, lname, town from customer where title <> 'Mr' and (town='Bingham' or town='Nicetown');

• select title, fname, lname, town from customer where title <> 'Mr' and town in ('Bingham','Nicetown');

SQL Queries

• select distinct town from customer where town between 'B' and 'N';

• select distinct town from customer where town between 'B' and 'Nz';

SQL Queries

• select fname, lname from customer where fname like '_a%';

• select customer_id, town from customer limit 5 offset 2;

SQL Queries

• select * from orderinfo where date_part('month', date_placed)=9;

• select * from orderinfo where date_placed>=cast('2004 07 21' as date);

• select date_shipped - date_placed from orderinfo;

More tables

• select customer.fname, orderinfo.date_placed from customer, orderinfo where customer.fname='Ann' and customer.lname='Stones' and customer.customer_id=orderinfo.customer_id;

• select description, cost_price, barcode_ean from item, barcode where barcode.item_id=item.item_id order by cost_price;

More tables

• select cu.fname, oi.date_placed from customer cu, orderinfo oi where cu.fname='Ann' and cu.lname='Stones' and cu.customer_id=oi.customer_id;

More tables

• select customer.fname, customer.lname, orderinfo.date_placed, item.description, orderline.quantity from customer, orderinfo, orderline, item where customer.customer_id=orderinfo.customer_id and orderinfo.orderinfo_id=orderline.orderinfo_id and orderline.item_id=item.item_id and customer.fname='Ann' and customer.lname='Stones';

More tables

select customer.fname, customer.lname, orderinfo.date_placed, item.description, orderline.quantity from customer

join orderinfo on customer.customer_id=orderinfo.customer_id

join orderline on orderinfo.orderinfo_id=orderline.orderinfo_id

join item on orderline.item_id=item.item_idwhere customer.fname='Ann' and

customer.lname='Stones';

SQL Queries

• select count(*) from customer where town='Bingham';

• select count(*), lname, town from customer group by town, lname;

• select count(*), lname, town from customer group by town, lname order by town, lname;

SQL Queries

• select count(*), town from customer group by town having count(*)>1;

• select count(*), lname, town from customer where town <> 'Lincoln' group by lname, town having count(*)>1;

• select count(*), lname, town from customer where town <> 'Lincoln' group by lname, town order by town;

SQL queries

• select customer_id from customer where phone IS NULL;

• select count(phone) from customer;

• select count(distinct town) as "distinct", count(town) as "all" from customer;

SQL Queries

• select avg(shipping) from orderinfo;

• select avg(distinct shipping) from orderinfo;

Subquery

• select * from item where cost_price>cast(7.249 as numeric(7,2));

• select * from item where cost_price> (select avg(cost_price) from item);

• select * from item where cost_price> (select avg(cost_price) from item) and sell_price < (select avg(sell_price) from item);

Subquery

• select * from stock where item_id in (select item_id from item where cost_price > cast(10.0 as numeric(7,2)));

• select oi.date_placed from orderinfo oi where oi.customer_id= (select c.customer_id from customer c where c.customer_id=oi.customer_id and town='Bingham');

Subquery

• select i.item_id from item i where i.item_id not in (select i.item_id from item i, stock s where i.item_id=s.item_id);

Join

• select i.item_id, s.quantity from item i left outer join stock s on i.item_id=s.item_id;

• select i.item_id, i.cost_price, s. quantity from item i left outer join stock s on i.item_id=s.item_id and s.quantity >2 where i.cost_price > cast(5.0 as numeric(7,2));

View

• create view item_price as select item_id, description::varchar(10), sell_price as price from item where sell_price <=20.0;

• select * from item_price;

• Drop view item_price;

Transactions

Initial StateBEGIN

First SQLSecond SQL

Rollback

Initial State BEGIN

First SQLSecond SQL

COMMIT…

Transactions

create table ttest1 (ival1 integer,sval1 varchar(64)

);

create table ttest2 ( ival2 integer, sval2 varchar(64));

Transactions

• insert into ttest1(ival1, sval1) values(1, 'David');

• begin;update ttest1 set sval1='Dave' where ival1=1;select sval1 from ttest1 where ival1=1;rollback;

• select sval1 from ttest1 where ival1=1;

Transactionsdelete from ttest1;delete from ttest2;insert into ttest1(ival1, sval1) values (1, 'David');

begin;insert into ttest2(ival2, sval2) values (42, 'Arthur');update ttest1 set sval1='Robert' where ival1=1;

select * from ttest1;select * from ttest2;-------------------Rollback;select * from ttest1;select * from ttest2;

Functions

• create language plpgsql;

• create function add_one(int4) returns int4 as 'begin return $1+1; end; 'language 'plpgsql';

• select add_one(2) as answer;

• Drop function add_one(int4);

Procedurecreate table reorders ( item_id integer, message text);

-- reorders-- scan the stock table to raise reorders of item low on stock

create function reorders(min_stock int4) returns integer as $$declare reorder_item integer; reorder_count integer; stock_row stock%rowtype; msg text;

Procedurebegin select count(*) into reorder_count from stock where quantity <= min_stock; for stock_row in select * from stock where quantity <= min_stock loop declare item_row item%rowtype; begin select * into item_row from item where item_id = stock_row.item_id; msg = 'order more ' || item_row.description || 's at ' || to_char(item_row.cost_price,'99.99'); insert into reorders values (stock_row.item_id, msg); end; end loop; return reorder_count;end;$$ language plpgsql;

select reorders(3);

select * from reorders;

Triggers

• Trigger: can be used to execute a stored procedure when certain actions are taken, like INSERT, DELETE, UPDATE in a table.

• The combination of stored procedures and triggers gives us the power to enforce quite sophisticated business rules (such as defined constraints)

• To use a trigger, we need to first define a trigger procedure, then create the trigger which will execute the trigger procedure.

Triggers

• A trigger procedure is created with the CREATE FUNCTION command, declaring it as a function with no arguments and a return type of trigger.

• The function must be declared with no arguments even if it expects to receive arguments specified in CREATE TRIGGER — trigger, arguments are passed via TG_ARGV,

Triggerscreate function reorder_trigger() returns trigger AS $$declare mq integer; item_record record;begin mq := tg_argv[0]; raise notice 'in trigger, mq is %', mq; if new.quantity <= mq then select * into item_record from item where item_id = new.item_id; insert into reorders values (new.item_id, item_record.description); end if; return NULL;end;$$ language plpgsql;

create trigger trig_reorder after insert or update ON stockfor each row execute procedure reorder_trigger(3);

update stock set quantity=3 where item_id=1;

select * from reorders;

Triggers

• Drop triggers– drop trigger trig_reorder4 on stock

– drop function reorder_trigger3()

Triggerscreate function customer_trigger() returns trigger AS $$declare order_record record;begin -- about to delete a customer -- disallow if orders pending select * into order_record from orderinfo where customer_id = old.customer_id and date_shipped is NULL; if not found then -- all OK, delete of customer can proceed raise notice 'deletion allowed: no outstanding orders'; raise notice 'old.customer_id is %', old.customer_id; return NULL;

-- for referential integrity we have to tidy up -- we will need to delete all completed orders -- but first delete the information about the orders

Triggersfor order_record in select * from orderinfo where customer_id = old.customer_id loop delete from orderline where orderinfo_id = order_record.orderinfo_id; end loop; -- now delete the order records delete from orderinfo where customer_id = old.customer_id;

-- return the old record to allow customer to be deleted return old; else -- orders present return NULL to prevent deletion raise notice 'deletion aborted: outstanding orders present'; return NULL; end if;end;$$ language plpgsql;

Triggerscreate trigger trig_customer before delete on customerfor each row execute procedure customer_trigger();

update orderinfo set date_shipped=NULL where orderinfo_id=3;select * from orderinfo;

delete from customer where customer_id=15;select * from orderinfo;

delete from customer where customer_id=3;select * from orderinfo;