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README.md

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+Project Name: BookShop
+Created by : Abdulla Rahman
+Roll: 1907030

bookShopPLSQL.sql

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+--printing name and email from customers (Basic pl/sql structure)
+set serveroutput on
+declare cus_name customers.customer_name%type;
+email varchar(50);
+begin
+    select customer_name, email into cus_name,email from customers where customer_id = 5001;
+    dbms_output.put_line('Name:' || cus_name || ' Email:'||email);
+end;
+/
+
+--use of rowtype
+set serveroutput on
+declare orders_row ORDERS%rowtype;
+begin 
+    select order_id into orders_row.order_id from orders where order_id = 7001;
+    dbms_output.put_line('id:' || orders_row.order_id );
+end;
+/
+
+
+
+--insert or set default value
+set serveroutput on
+declare
+    order_id ORDERS.ORDER_ID%type:=7010;
+    product_id ORDERS.PRODUCT_ID%type := 3001;
+    customer_id Orders.Customer_id%type := 5001;
+    quantity ORDERS.QUANTITY%type := 2;
+
+begin
+    INSERT INTO orders (order_id, product_id, customer_id, quantity) VALUES (order_id, product_id, customer_id, quantity);
+end;
+/
+
+--cursor
+set serveroutput on 
+declare
+cursor c is select * from customers;
+c_row customers%rowtype;
+begin
+ open c;
+ fetch c into c_row.customer_id,c_row.customer_name,c_row.address,c_row.phone,c_row.email;
+ dbms_output.put_line('id:'|| c_row.customer_id || ' name:'||c_row.customer_name);
+ close c;
+end;
+/
+
+--cursor with loop
+set serveroutput on 
+declare
+cursor c is select * from customers;
+c_row customers%rowtype;
+begin
+ open c;
+ fetch c into c_row.customer_id,c_row.customer_name,c_row.address,c_row.phone,c_row.email;
+ while c%found loop
+ dbms_output.put_line('id:'|| c_row.customer_id || ' name:'||c_row.customer_name);
+ dbms_output.put_line('row_count: ' || c%rowcount);
+ fetch c into c_row.customer_id,c_row.customer_name,c_row.address,c_row.phone,c_row.email; 
+ end loop;
+ close c;
+end;
+/
+
+--array
+set serveroutput on
+declare
+i number;
+c_name customers.customer_name%type;
+TYPE NAMEARRAY is VARRAY(5) of CUSTOMERS.CUSTOMER_NAME%type;
+myarray NAMEARRAY:= NAMEARRAY();
+
+begin
+i:= 1;
+for x in 5001..5005
+loop 
+    select customer_name into c_name from customers where customer_id = x;
+    myarray.EXTEND();
+    myarray(i):= c_name;
+    i:=i+1;
+end loop;
+
+i:=1;
+while i<=myarray.count
+loop
+    dbms_output.put_line(myarray(i));
+    i:=i+1;
+end loop;
+end;
+/
+
+--array with extend function
+set serveroutput on
+declare
+i number;
+c_name customers.customer_name%type;
+TYPE NAMEARRAY is VARRAY(5) of CUSTOMERS.CUSTOMER_NAME%type;
+myarray NAMEARRAY:= NAMEARRAY('Customer 1','Customer 2','Customer 3','Customer 4','Customer 5');
+
+begin
+i:= 1;
+for x in 5001..5005
+loop 
+    select customer_name into c_name from customers where customer_id = x;
+    myarray(i):= c_name;
+    i:=i+1;
+end loop;
+
+i:=1;
+while i<=myarray.count
+loop
+    dbms_output.put_line(myarray(i));
+    i:=i+1;
+end loop;
+end;
+/
+
+--if/else
+set serveroutput on;
+declare
+i number;
+product_id PRODUCTS.PRODUCT_ID%type;
+seller_id PRODUCTS.SELLER_ID%type;
+begin
+    i:=1;
+    for x in 3001..3015
+    loop
+        select product_id,seller_id into product_id,seller_id from products where product_id = x;
+        IF seller_id = 1001 then
+            dbms_output.put_line(product_id || ' sold by ABC Books');
+        ELSIF seller_id = 1002 then
+            dbms_output.put_line(product_id || ' sold by XYZ Bookstore');
+        else
+            dbms_output.put_line(product_id || ' sold by other sellers'); 
+    end if;   
+    end loop;
+end;
+/
+
+--simple procedure for printing customer name according to customer_id (IN)
+
+create or replace procedure proc(var1 in customers.customer_id%type) is
+var2 varchar2(30);
+begin
+select customer_name into var2 from customers where customer_id = var1;
+dbms_output.put_line('customer name:'|| var2);
+end;
+/
+
+set serveroutput on
+declare 
+begin
+proc(5005);
+end;
+/
+
+
+--in out
+
+create or replace procedure proc2(varId in customers.customer_id%type, varName out customers.customer_name%type,varEmail out customers.email%type) is
+begin
+select customer_name,email into varName,varEmail from customers where customer_id = varId;
+end;
+/
+
+set serveroutput on
+declare 
+cName Customers.customer_name%type;
+cEmail CUSTOMERS.EMAIL%type;
+begin
+proc2(5005,CName,CEmail);
+dbms_output.put_line('Name:'||cName || ' Email: '||cEmail);
+end;
+/
+
+--function (take input of a customer id and print his email)
+create or replace function func(varId in Customers.customer_id%type) return varchar as
+cName customers.customer_NAME%type;
+begin
+select customer_NAME into cName from customers where customer_id = varId;
+return cName;
+end;
+/
+
+
+set serveroutput on
+declare 
+cName customers.customer_name%type;
+cEmail customers.Email%type;
+begin
+cName:=func(5001);
+select email into cEmail from customers where customer_name = cName;
+dbms_output.put_line('Email: '||cEmail);
+end;
+/
+
+
+--Trigger
+
+-- Creating trigger to update total_price
+CREATE OR REPLACE TRIGGER update_total_price
+BEFORE INSERT OR UPDATE ON orders
+FOR EACH ROW
+BEGIN
+        SELECT price * :NEW.quantity
+        INTO :NEW.total_price
+        FROM products
+        WHERE product_id = :NEW.product_id;
+END;
+/
+
+-- Checking Availabity when placing order
+CREATE OR REPLACE TRIGGER place_order
+BEFORE INSERT ON orders
+FOR EACH ROW
+DECLARE
+    product_quantity NUMBER;
+BEGIN
+    SELECT count
+    INTO product_quantity
+    FROM products
+    WHERE product_id = :NEW.product_id;
+
+    IF product_quantity < :NEW.quantity THEN
+        RAISE_APPLICATION_ERROR(-20001, 'Cannot place order. Stock out.');
+    ELSE
+        UPDATE products
+        SET count = count - :NEW.quantity
+        WHERE product_id = :NEW.product_id;
+    END IF;
+END;
+/

bookshopDDL.sql

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+drop table orders;
+drop table products;
+drop table books;
+drop table sellers;
+drop table customers;
+
+create table books(
+    id NUMBER PRIMARY KEY,
+    title varchar(50) not null,
+    author varchar(20) not null,
+    category varchar(20)
+);
+
+create table sellers(
+    Seller_id number primary key,
+    seller_name varchar(30) not null,
+    phone NUMBER not null,
+    email varchar(30)
+);
+
+create table customers(
+    customer_id number PRIMARY key,
+    customer_name varchar(30),
+    address VARCHAR(50),
+    phone number,
+    email varchar(30)
+);
+
+create table products (
+    product_id number primary key,
+    book_id number not null,
+    seller_id number not null,
+    price number not null check (price>0),
+    count number not null check (count>=0),
+    FOREIGN key (book_id) references books(id),
+    FOREIGN key (seller_id) REFERENCEs sellers(seller_id)
+);
+
+CREATE TABLE orders (
+    order_id NUMBER PRIMARY KEY,
+    order_date date DEFAULT SYSDATE,
+    product_id NUMBER NOT NULL,
+    customer_id NUMBER NOT NULL,
+    quantity NUMBER CHECK (quantity > 0),
+    total_price NUMERIC(6,2),
+    status VARCHAR(20) DEFAULT 'In progress' CHECK (status IN ('In progress', 'Shipped', 'Delivered')),
+    FOREIGN KEY (product_id) REFERENCES products(product_id),
+    FOREIGN KEY (customer_id) REFERENCES customers(customer_id)
+);
+
+-- Creating trigger to update total_price
+CREATE OR REPLACE TRIGGER update_total_price
+BEFORE INSERT OR UPDATE ON orders
+FOR EACH ROW
+BEGIN
+        SELECT price * :NEW.quantity
+        INTO :NEW.total_price
+        FROM products
+        WHERE product_id = :NEW.product_id;
+END;
+/
+
+-- Checking Availabity when placing order
+CREATE OR REPLACE TRIGGER place_order
+BEFORE INSERT ON orders
+FOR EACH ROW
+DECLARE
+    product_quantity NUMBER;
+BEGIN
+    SELECT count
+    INTO product_quantity
+    FROM products
+    WHERE product_id = :NEW.product_id;
+
+    IF product_quantity < :NEW.quantity THEN
+        RAISE_APPLICATION_ERROR(-20001, 'Cannot place order. Stock out.');
+    ELSE
+        UPDATE products
+        SET count = count - :NEW.quantity
+        WHERE product_id = :NEW.product_id;
+    END IF;
+END;
+/
+
+
+