Normalization
- 1. Normalization Presenting by: 1. Muzamil Raza 03087311722
- 2. what is Normalization? • The process of producing a simpler and more reliable database structure is called normalization. • We can only produce a simpler and more reliable database structure by eliminate redundancy from the database structure. • Redundancy means duplication of data in multiple files • Many problems can be occur in DB structure because of Redundancy.
- 3. Purposes of Normalization 1. It makes the database design efficient in performance. 2. It reduces the amount of data if possible. 3. It makes the database design free of update, insertion and deletion anomalies/problems. 4. It makes the design according the rules of relational databases. 5. It identifies relationship b/w entities. 6. It makes a design that allows simple retrieval of data. 7. It simplifies data maintenance and reduces the need to restructure data. Characteristics of Normalized Database 1. Each relation must have a key field. 2. All fields must contain atomic data. 3. There must be no repeating fields. 4. Each table must contain information about a single entity. 5. Each field in a relation must depend on key fields. 6. All non-key fields must be mutually independent.
- 4. Data Sources Users User’s Requirement Specification Sources like Data dictionary & Model Un-normalized Form (UNF) First Normal Form (1NF) Second Normal Form (2NF) Third Normal Form (3NF) Boyce-Codd Normal Form (BCNF) Fourth Normal Form (4NF) Normal Form (NF) Fifth Normal Form (5NF) Transfer attributes into Table Format Remove Partial Dependencies Remove Repeating Groups Remove Transitive Dependencies Make sure every determinate is candidate key Remove Multi-Valued Dependencies Remove Join Dependencies Normalization stop
- 5. Functional Dependency • Functional dependency is a relationship between attributes. • It means that if the value of one attribute is known, it is possible to obtain the value of another attribute. • Sign of FD is “->”, The attribute on the left side of the sign known as Determinate. Suppose there is a table name student as bellow Std-Roll.No Reg.No Name Address 1 Adp001 Muzamil Khanewal 2 Adp002 Manzar Kabierwalw 3 Adp003 Muzamil Khanewal 4 Adp004 Sheraz khanewal If I say that Address Name valid/Not-v
- 6. Exercise Std-Roll.No Reg.No Name Address 1 Adp001 Muzamil Khanewal 2 Adp002 Manzar Kabierwala 3 Adp003 Muzamil Khanewal 4 Adp004 Sheraz kahanewal If I say that Name Address valid/Not-v If I say that Std-Roll.No Name valid/Not-v If I say that Reg.No Address valid/Not-v 1 2 3
- 7. Types of Functional Dependency 1. Trivalent: The dependency of an attribute on a set of attribute is known as trivalent functional dependency attribute if the set of attribute include that attribute. (we have no new information) In this table we assigned supposed names to the attributes. Std-Roll.No (I) Reg.No (R) Name (N) Address (A) 1 Adp001 Muzamil Khanewal 2 Adp002 Manzar Kabierwala 3 Adp003 Muzamil Khanewal 4 Adp004 Sheraz kahanewal If I say that IN N Trivalent FD In first case If I say that IN INA Non-Trivalent FD In second case R RINA Finding new stop
- 8. Non-Trivalent FD Exercise Std-Roll.No (I) Reg.No (R) Name (N) Address (A) Class (C) 1 Adp001 Muzamil Khanewal ADPcs 2 Adp002 Manzar Kabierwala ADPcs 3 Adp003 Muzamil Khanewal ADPcs 4 Adp004 Sheraz kahanewal ADPcs Case 3 I RC valid/Not-v Case 1 IR NA valid/Not-v Case 4 IR NAC valid/Not-v Case 5 N AC valid/Not-v Case 6 NA I valid/Not-v Case 2 R IC valid/Not-v
- 9. Closure set of attribute • Before go to normalization we should know the entire set of dependencies, and we can compute it only because of closure set of attribute. • With closure we can find all FD’s easily Example Std-Roll.No (I) Reg.No (R) Name (N) Address (A) Class (C) 1 Adp001 Muzamil Khanewal ADPcs 2 Adp002 Manzar Kabierwala ADPcs 3 Adp003 Muzamil Khanewal ADPcs 4 Adp004 Sheraz kahanewal ADPcs Find (R)+ Solution (R)+ R RIC RICN RCINA(R)+ stop R IC IC N RI N N A
- 10. Closure set of attribute Exercise Std-Roll.No (I) Reg.No (R) Name (N) Address (A) Class (C) 1 Adp001 Muzamil Khanewal ADPcs 2 Adp002 Manzar Kabierwala ADPcs 3 Adp003 Muzamil Khanewal ADPcs 4 Adp004 Sheraz kahanewal ADPcs Find (IC)+ Solution (IC)+ IC ICN ICNA(IC)+ R IC IC N RI N N A stop
- 11. Equivalence of functional dependency After this slide we will able to compare two different set of functional dependency. Example Std-Roll.No (I) Reg.No (R) Name (N) Address (A) Class (C) 1 Adp001 Muzamil Khanewal ADPcs 2 Adp002 Manzar Kabierwala ADPcs 3 Adp003 Muzamil Khanewal ADPcs 4 Adp004 Sheraz kahanewal ADPcs I N IN A R IA R C I NA R R.S (I)+ INA (IN)+ INA (R)+ INAC (I)+ INA (IN)+ INA (R)+ INAC L.S IC L.S R.S L.S R.S L.S R.S L.S R.S What we have to find? L.S R.S R.S L.S stop
- 12. Irreducible set of FD (canonical Form) • It means whether any given functional dependency there exist some redundant element or not? • If there exist some redundant element we must remove it from functional dependency. 1. First we will apply decomposition role. 2. Second we will have single value for every determinate. 3. Third will compute closure of every determinate one by one and we will have to ignoring and considering essential and non-essential dependencies 4. Than we will remove redundant element. We have these functional dependencies: Decomposed Form stop R IC IC NA RI N N A R I IC N RI N N A R C IC N
- 13. Canonical form Closure of 1st FD (R)+ RI (R)+ Decomposed Form Closure of 2nd FD (R)+ RC (R)+ Closure of 3rd FD (IC)+ ICNA (IC)+ Closure of 4th FD (IC)+ ICA (IC)+ Closure of 5th FD (N)+ NA (N)+ Canonical Form R I R C N A IC N stop R I IC N RI N N A R C IC A Closure of 5th FD (RI)+ RIN (RI)+ RI N
- 14. Key, Super, candidate, primary key • We will discuses briefly again because it is very important. Relation name stu R IC IC N RI N N A Super key Candidate key Primary key Yes Yes If selected by DBA Yes No Yes No Yes Yes If selected by DBA Std-Roll.No (I) Reg.No (R) Name (N) Address (A) Class (C) 1 Adp001 Muzamil Khanewal ADPcs 2 Adp002 Manzar Kabierwala ADPcs 3 Adp003 Muzamil Khanewal ADPcs 4 Adp004 Sheraz kahanewal ADPcs stop Explain with diagram
- 15. Review 1. We briefly studied that what is normalization 2. Purposes and Characteristics of normalization 3. Then we understand the normalization diagram. 4. we understand that what is FD and its types with examples (trivalent & non-trivalent FD). 5. We studied Closure set of attributes and how to compute it with example. 6. We studied equivalence of FD and how to compute it. 7. What is irreducible set of FD or what is canonical form . 8. We briefly studied about some keys. 9. How to find candidate key quickly. Now we will study about normalization its types and how we use functional dependency as a tool in normalization.
- 16. Types of Normalization we will study • There are three types of Normalization that are essential for a effective database designe. 1st Normal Form (1NF) 2nd Normal Form (2NF) 3rd Normal Form (3NF) There are some other types but these are not important for us. Before this we will discuss about partial and transitive dependency.
- 17. UNF StdID StdName SocietyID SocName SupID Supervisor Position 123 Masood 001 003 Urdu Maths 1 2 Mr.Waseem Ms.Chauhdry Chairman Member 132 zahra 001 Urdu 1 Mr.Waseem Member 142 javed 002 005 008 English Physics Biology 1 3 4 Mr.waseem Mr.Liaqat Miss Yasmeen Member Chairman Member This table is not a relational table.There is no primary key no any foreign key in this relation. The relation is consist of multi-valued attributes. The above table is in UNF. We will apply first three normal forms to the above relation.
- 18. 1NF • First normal form (1NF) is a property of a relation in a relational database. A relation is in first normal form if and only if the domain of each attribute contains only atomic (indivisible) values, and the value of each attribute contains only a single value from that domain. StdID StdName 123 Masood 132 Zahra 142 javed Student relation Student_in_Society relation First we convert the whole table in to tow parts Student and student_in_society relation, then we use the primary key of first table in second table as foreign key, and also make a primary key in the second table. StdID SocietyID SocName SupID Supervisor Position 123 001 Urdu 1 Mr.Waseem Chairman 123 003 Maths 2 Ms.Chauhdry Member 132 001 Urdu 1 Mr.Waseem Member 142 002 English 1 Mr.Waseem Member 142 005 Physics 3 Mr.Liaqat Chairman 142 008 Biology 4 Miss Yasmeen Member stop
- 19. 2NF • StdID and SocietyID Belongs to Prime attribute because they are the part of primary Key . • Position, SocName, SupID are Belongs to Non-Prime attribute because they are Not the Part of primary key. • When a Non-prime attribute is dependent on a prime attribute this called partial dependency. StdID,SocietyID Position Full functioanlly dependecy What is partial dependency? StdID SocietyID SocName SupID Supervisor Position 123 001 Urdu 1 Mr.Waseem Chairman 123 003 Maths 2 Ms.Chauhdry Member 132 001 Urdu 1 Mr.Waseem Member 142 002 English 1 Mr.Waseem Member 142 005 Physics 3 Mr.Liaqat Chairman 142 008 Biology 4 Miss Yasmeen Member SocietyID SocName SocietyID SupID Partial dependecy Partial dependecy stop
- 20. 2NF A relation will be in 2NF if it complete the requirements of 1NF and remove the partial dependencies from the relation. StdID StdName 123 Masood 132 Zahra 142 javed Student relation Student_in_Society relation For 2NF we will decompose the student_in_society relation in two parts as: student_in_society and Society relation. SocietyID SocName SupID Supervisor 001 Urdu 1 Mr.Waseem 002 English 1 Mr.Waseem 003 Math 2 Ms.Chauhdry 005 Physics 3 Mr.Liaqat 008 Biology 4 Miss Yasmeen StdID SocietyID Position 123 001 Chairman 123 003 Member 132 001 Member 142 002 Member 142 005 Chairman 142 008 Member Society relation stop
- 21. 3NF • SocietyID is a Prime attribute. • SupID and Supervisor are Belongs to Non-Prime attribute because they are Not the Part of primary key. • When a Non-prime attribute is dependent on a Non-prime attribute this called transitive dependency. SocietyID SupID What is transitive dependency? SupID Supervisor Full functional dependecy Transitive dependecy SocietyID SocName SupID Supervisor 001 Urdu 1 Mr.Waseem 002 English 1 Mr.Waseem 003 Math 2 Ms.Chauhdry 005 Physics 3 Mr.Liaqat 008 Biology 4 Miss Yasmeen In society table the stop
- 22. 3NF A relation will be in 3NF if it complete the requirements of 1NF, 2NF and remove the transitive dependencies from the relation. supID Supervisor 1 Mr.Waseem 2 Ms.Chauhdry 3 Mr.Liaqat 4 Miss Yasmeen Society_in_Teacher relation For 3NF we will decompose the society relation in two parts as: society_in_ Teachter and Society relation. SocietyID SocName SupID 001 Urdu 1 002 English 1 003 Math 2 005 Physics 3 008 Biology 4 Society relation stop
- 23. UNF of relation StdID StdName SocietyID SocName SupID Supervisor Position 123 Masood 001 003 Urdu Maths 1 2 Mr.Waseem Ms.Chauhdry Chairman Member 132 zahra 001 Urdu 1 Mr.Waseem Member 142 002 005 008 English Physics Biology 1 3 4 Mr.waseem Mr.Liaqat Miss Yasmeen Member Chairman Member
- 24. UNF of relation StdID StdName Muzamil Khanewal Manzar Kabierwala Muzamil Khanewal Student relation supID Supervisor 1 Mr.Waseem 2 Ms.Chauhdry 3 Mr.Liaqat 4 Miss Yasmeen Society_in_Teacher relation SocietyID SocName SupID 001 Urdu 1 002 English 1 003 Math 2 005 Physics 3 008 Biology 4 Society relation Student_in_Society relation StdID SocietyID Position 123 001 Chairman 123 003 Member 132 001 Member 142 002 Member 142 005 Chairman 142 008 Member stop
- 25. Thanks!