E-COMMERCE JOBS This project (Project number: HU/01/B/F/PP ) is carried out with the financial support of the Commssion of the European Communities under the Leonardo da Vinci Programme 1 Database Models Ver: 1.0 E-Commerce Databases Database models

E-COMMERCE JOBS This project (Project number: HU/01/B/F/PP ) is carried out with the financial support of the Commssion of the European Communities under the Leonardo da Vinci Programme 2 Database Models Ver: 1.0 Relational Databases Entities (e.g. Customer, Products...) Relationships (e.g. a Customer orders many Products) Entity Relationship Diagram (ERD) Normal Forms (to exclude duplicity of data and resulting update problems)

E-COMMERCE JOBS This project (Project number: HU/01/B/F/PP ) is carried out with the financial support of the Commssion of the European Communities under the Leonardo da Vinci Programme 3 Database Models Ver: 1.0 Entity Type / Table Tables Attributes Records

E-COMMERCE JOBS This project (Project number: HU/01/B/F/PP ) is carried out with the financial support of the Commssion of the European Communities under the Leonardo da Vinci Programme 4 Database Models Ver: 1.0 Primary Keys Relationships Primary Key cus_id

E-COMMERCE JOBS This project (Project number: HU/01/B/F/PP ) is carried out with the financial support of the Commssion of the European Communities under the Leonardo da Vinci Programme 5 Database Models Ver: 1.0 Relationships Customer Product confirms sales n:m Customer Product confirms sales 1:n sold n:1 Relationships become Tables

E-COMMERCE JOBS This project (Project number: HU/01/B/F/PP ) is carried out with the financial support of the Commssion of the European Communities under the Leonardo da Vinci Programme 6 Database Models Ver: 1.0 Relationships Customer Table Sales Table Product Table

E-COMMERCE JOBS This project (Project number: HU/01/B/F/PP ) is carried out with the financial support of the Commssion of the European Communities under the Leonardo da Vinci Programme 7 Database Models Ver: 1.0 Entity Relationship Diagram Illustrating entity types and their relationships Input for the database design team which tables to create Customer Product confirms sales 1:n sold n:1

E-COMMERCE JOBS This project (Project number: HU/01/B/F/PP ) is carried out with the financial support of the Commssion of the European Communities under the Leonardo da Vinci Programme 8 Database Models Ver: 1.0 Redundancy Elimination First Normal Form –First Normal Form eliminates repeating groups by putting each into a separate table and connecting them with a one-to-many relationship. Second Normal Form –Second Normal Form eliminates functional dependencies on a partial key by putting the fields in a separate table from those that are dependent on the whole key. Third Normal Form –Third Normal Form eliminates functional dependencies on non-key fields by putting them in a separate table. At this stage, all non-key fields are dependent on the key, the whole key and nothing but the key. -> Data are normalised !

E-COMMERCE JOBS This project (Project number: HU/01/B/F/PP ) is carried out with the financial support of the Commssion of the European Communities under the Leonardo da Vinci Programme 9 Database Models Ver: 1.0 1Nf to 2NF Example Separate into different entities/tables Check that no attributes are dependent on key-subset (e.g. warehouse-address being dependent on key warehouse)

E-COMMERCE JOBS This project (Project number: HU/01/B/F/PP ) is carried out with the financial support of the Commssion of the European Communities under the Leonardo da Vinci Programme 10 Database Models Ver: 1.0 2NF to 3NF Example Identify non-key fields which would be keys of a separate table Separate out these tables

E-COMMERCE JOBS This project (Project number: HU/01/B/F/PP ) is carried out with the financial support of the Commssion of the European Communities under the Leonardo da Vinci Programme 11 Database Models Ver: 1.0 4NF / 5NF Employee Language Competence 1:nn:1 Skill 1:n employee_id, skill_id, lang_id Speaking Capability

E-COMMERCE JOBS This project (Project number: HU/01/B/F/PP ) is carried out with the financial support of the Commssion of the European Communities under the Leonardo da Vinci Programme 12 Database Models Ver: 1.0 Exercise 1 Master Example 1 Design the Entity Realtionship Diagram for a typical customer and product sales situation including stock control Identify the primary keys, the relationships, and the attributes required within each table Check against the 3NF Do this work in about 1 hour

E-COMMERCE JOBS This project (Project number: HU/01/B/F/PP ) is carried out with the financial support of the Commssion of the European Communities under the Leonardo da Vinci Programme 13 Database Models Ver: 1.0 Exercise 2 Master Example 2 Design the Entity Realtionship Diagram for a typical e-newspaper ordering site with customers, newspapers to select, newspapers to renew and to administer sales and payments Identify the primary keys, the relationships, and the attributes required within each table Check against the 3NF Do this work in about 1 hour

E-COMMERCE JOBS This project (Project number: HU/01/B/F/PP ) is carried out with the financial support of the Commssion of the European Communities under the Leonardo da Vinci Programme 14 Database Models Ver: 1.0 References F. Codd, "A Relational Model of Data for Large Shared Data Banks", Comm. ACM 13 (6), June 1970, pp The original paper introducing the relational data model. F. Codd, "Normalized Data Base Structure: A Brief Tutorial", ACM SIGFIDET Workshop on Data Description, Access, and Control, Nov , 1971, San Diego, California, E.F. Codd and A.L. Dean (eds.). An early tutorial on the relational model and normalization. E.F. Codd, "Further Normalization of the Data Base Relational Model", R. Rustin (ed.), Data Base Systems (Courant Computer Science Symposia 6), Prentice-Hall, Also IBM Research Report RJ909. The first formal treatment of second and third normal forms. C.J. Date, An Introduction to Database Systems (third edition), Addison-Wesley, An excellent introduction to database systems, with emphasis on the relational. R. Fagin, "Multivalued Dependencies and a New Normal Form for Relational Databases", ACM Transactions on Database Systems 2 (3), Sept Also IBM Research Report RJ1812. The introduction of fourth normal form. R. Fagin, "Normal Forms and Relational Database Operators", ACM SIGMOD International Conference on Management of Data, May 31-June 1, 1979, Boston, Mass. Also IBM Research Report RJ2471, Feb The introduction of fifth normal form. W. Kent, "A Primer of Normal Forms", IBM Technical Report TR02.600, Dec An early, formal tutorial on first, second, and third normal forms. T.-W. Ling, F.W. Tompa, and T. Kameda, "An Improved Third Normal Form for Relational Databases", ACM Transactions on Database Systems, 6(2), June 1981, One of the first treatments of inter-relational dependencies.