SOLID - An object oriented design technique

 

 

Stands for (acronym)	Concept
S	SRP	Single responsibility principle a class should have only a single responsibility (i.e. only one potential change in the software's specification should be able to affect the specification of the class)
O	OCP	Open/closed principle “software entities … should be open for extension, but closed for modification.”
L	LSP	Liskov substitution principle “objects in a program should be replaceable with instances of their subtypes without altering the correctness of that program.” See also design by contract.
I	ISP	Interface segregation principle “many client-specific interfaces are better than one general-purpose interface.”
D	DIP	Dependency inversion principle one should “Depend upon Abstractions. Do not depend upon concretions.”

Sample SQL Database script with data

DB Diagram:

DB Script:

create table zipcodes (

  zip int primary key,

  city  varchar(30),

  State varchar(20));

create table employees (

  eno  varchar(10) primary key,

  ename  varchar(30),

  zip  int references zipcodes,

  hire_date date);

create table books (

  bno  int primary key,

  bname  varchar(30),

  qoh  int not null,

  price  dec(6,2) not null);

create table customers (

  cno   int primary key,

  cname  varchar(30),

  street varchar(30),

  zip  int  references zipcodes,

  phone  char(12));

create table orders (

  ono  int  primary key,

  cno  int  references customers,

  eno  varchar(10)  references employees,

  received date,

  shipped date

);

create table odetails (

  ono  int  references orders,

  bno  int  references books,

  quantity int not null,

  primary key (ono, bno));

insert into zipcodes values (98225, 'Bellingham', 'WA'); 

insert into zipcodes values (95388, 'Winton', 'CA'); 

insert into zipcodes values (44242, 'Stow', 'OH'); 

insert into zipcodes values (61536, 'Hanna city', 'IL'); 

insert into zipcodes values (01254, 'Richmond', 'MA'); 

insert into zipcodes values (95124, 'San Jose', 'CA'); 

insert into zipcodes values (95382, 'Turlock', 'MA'); 

insert into zipcodes values (95380, 'Turlock', 'CA');

insert into employees values ('P0239400', 'Jones Hoffer',98225, '2000-12-12'); 

insert into employees values ('P0239401', 'Jeffrey Prescott',95388, '2006-01-01'); 

insert into employees values ('P0239402', 'Fred NcFaddeb',95124, '2008-09-01');

insert into books values (10506, 'Accounting 101',200, 129.99); 

insert into books values (10507, 'Management 101',159, 109.99); 

insert into books values (10508, 'Fraud Cases',190, 179.99); 

insert into books values (10509, 'CPA Review',65, 299.99); 

insert into books values (10601, 'Peachtree for Dummies',322, 49.99); 

insert into books values (10701, 'Financial Accounting',129, 164.99); 

insert into books values (10800, 'Managerial Accounting',155, 114.99); 

insert into books values (10900, 'Cost Accounting',122, 119.99); 

insert into books values (10901, 'Intermediate Accounting',123, 164.99); 

insert into books values (10902, 'XBRL in Nutshell',124, 109.99);

insert into customers values (23511, 'Michelle Kuan', '123 Main St.',98225, '360-636-5555'); 

insert into customers values (23512, 'George Myer', '237 Ash Ave.',95124, '312-678-5555'); 

insert into customers values (23513, 'Richard Gold', '111 Inwood St.',95124, '312-883-7337'); 

insert into customers values (23514, 'Robert Smith', '54 Gate Dr.',95388, '206-832-1221'); 

insert into customers values (23515, 'Christopher David', '777 Loto St.',98225, '360-458-9878'); 

insert into customers values (23516, 'Adam Beethoven', '234 Park Rd..',95380, '209-546-7299'); 

insert into customers values (23517, 'Lidwig Bach', '5790 Walnut St.',95382, '209-638-2712');

insert into orders values (1020, 23511, 'P0239400', '2009-10-18', '2009-10-20'); 

insert into orders values (1021, 23511, 'P0239400', '2009-10-29', '2009-10-31'); 

insert into orders values (1022, 23512, 'P0239401', '2009-11-10', '2009-11-13'); 

insert into orders (ONO, CNO, ENO, RECEIVED) values (1023, 23513, 'P0239402', '2009-11-15'); 

insert into orders (ONO, CNO, ENO, RECEIVED) values (1024, 23511, 'P0239400', '2009-11-16');

insert into odetails values (1020, 10506,1); insert into odetails values (1020, 10507,2); 

insert into odetails values (1020, 10508,2); insert into odetails values (1020, 10509,3); 

insert into odetails values (1021, 10601,4); insert into odetails values (1022, 10601,1); 

insert into odetails values (1022, 10701,2); insert into odetails values (1023, 10800,4); 

insert into odetails values (1023, 10900,1); insert into odetails values (1024, 10900,7);