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Karina Joyce E. LimboJedan TipuraBLIS-IIIRELATIONAL DATABASE MODEL:LOGICAL VIEW OF DATAANDKEYS
Logical View of Data Logical simplicity yields simpler and more  effective database design methodologies.
• The model was first proposed by E.F.Codd in   1970.
EntityAn entity is simply a person, place, event, or  thing for which we intend to collect data.Examples:❖ University -- S...
AttributesEach entity has certain characteristics known as  attributes.Examples:❖ Student -- Student  Number, Name, GPA, D...
Entities and Attributes     A grouping of related entities becomes  an entity set.Examples:❖ The STUDENT entity set contai...
Tables and TheirCharacteristics A table is perceived as a two-dimensional  structure composed of rows and columns. Each ...
 All values in a column must conform to the  same data format. Each column has a specific range of values  known as the ...
Table Name: STUDENTE   STU_FNAME   STU_INIT   STU_DOB   STU_HRS   STU_CLASS STU_GPA   STU_TRAN   DEPT                     ...
Relational Schema
Keys It is an attribute that determines the values of  other attributes within the entity.
 The key’s role is based on a concept known as  determination.  The shorthand notation for “A determines B”  is A     B. ...
Example:STU_NUM  STU_LNAME, STU_FNAME, STU_INIT
Functional Dependence Can be generalized to cover the case in which  the determining attribute values occur more  than on...
 Attribute A determines Attribute B (that is, B  is functionally dependent on A) if all of the  rows in the table that ag...
STUDENT CLASSIFICATIONHOURS COMPLETED            CLASSIFICATIONLess than 30               Fr30-59                      So6...
STU_HRS      STU_CLASS    But specific number of hours is not dependent on the classification. In other words, the classif...
Key AttributeAny attribute that is part of a key.Examples:STU_LNAME,STU_FNAME,STU_INIT,STU_PHONE     STU_HRS,STU_CLASS
Relational Database KeysSuperkey An attribute (or combination of attributes)  that uniquely identifies each entity in a t...
Example:In the STUDENT table..STU_NUMSTU_NUM, STU_LNAMESTU_NUM, STU_LNAME, STU_INIT
Candidate Key A minimal superkey. A superkey that does not  contain a subset of attributes that is itself a  superkey.
STU_NUM,STU_LNAMEis a superkey, but it is not a candidate key   because STU_NUM by itself is a candidate   key.
Controlled Redundancy -makes the relational database work. -tables within the database share common attributes that enable...
Table Name: PRODUCT    Primary Key: PROD_CODE   PROD_CODE VEND_CODE    Foreign key:   PROD_DESCRIPT                      P...
Primary Key -is usually underlined. - A candidate key selected to uniquely identify all other attribute values in any give...
Example:VENDOR (VEND_CODE, VEND_CONTACT, VEND_AREACODE, VEND_PHONE)PRODUCT (PROD_CODE, PROD_DESCRIPT, PROD_PRICE, PROD_ON_...
Secondary Key - An attribute used strictly for data retrieval purposes.
Example:    A customer date are stored in a CUSTOMER table. The customer number is the primary key; the secondary key is t...
Foreign Key     - An attribute in one table whose values  must either match the primary key in another  table or be null.
VENDOR VEND_CODE       PRODUCT VEND_CONTACT      PROD_CODE VEND_AREACODE     PROD_DESCRIPT VEND_PHONE        PROD_PRICE   ...
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Relational database model -report

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Relational database model -report

  1. 1. Karina Joyce E. LimboJedan TipuraBLIS-IIIRELATIONAL DATABASE MODEL:LOGICAL VIEW OF DATAANDKEYS
  2. 2. Logical View of Data Logical simplicity yields simpler and more effective database design methodologies.
  3. 3. • The model was first proposed by E.F.Codd in 1970.
  4. 4. EntityAn entity is simply a person, place, event, or thing for which we intend to collect data.Examples:❖ University -- Students, Faculty Members, Courses❖ Airlines -- Pilots, Aircraft, Routes, Supplier
  5. 5. AttributesEach entity has certain characteristics known as attributes.Examples:❖ Student -- Student Number, Name, GPA, Date of Enrollment, Data of Birth, Home Address, Phone Number, Major❖ Aircraft -- Aircraft Number, Data of Last Maintenance, Total Hours Flown, Hours Flown since Last Maintenance
  6. 6. Entities and Attributes A grouping of related entities becomes an entity set.Examples:❖ The STUDENT entity set contains all student entities.❖ The FACULTY entity set contains all faculty entities.❖ The AIRCRAFT entity set contains all aircraft entities
  7. 7. Tables and TheirCharacteristics A table is perceived as a two-dimensional structure composed of rows and columns. Each table row (tuple) represents a single entity within the entity set. Each column represents an attribute and each column has a distinct name. Each row/column intersection represents a single data value
  8. 8.  All values in a column must conform to the same data format. Each column has a specific range of values known as the attribute domain. The order of the rows and columns is immaterial to the DBMS Each table must have an attribute or a combination of attributes that uniquely identifies each row.
  9. 9. Table Name: STUDENTE STU_FNAME STU_INIT STU_DOB STU_HRS STU_CLASS STU_GPA STU_TRAN DEPT SFER CODE William C 12-Feb- 42 So 2.84 No BIOL 1975n Anne K 15-Nov- 81 Jr 3.27 Yes CIS 1981 Juliette F 23-Aug- 36 So 2.26 Yes ACCT 1969
  10. 10. Relational Schema
  11. 11. Keys It is an attribute that determines the values of other attributes within the entity.
  12. 12.  The key’s role is based on a concept known as determination. The shorthand notation for “A determines B” is A B. If A determines B, C and D, you write A B, C, D.
  13. 13. Example:STU_NUM STU_LNAME, STU_FNAME, STU_INIT
  14. 14. Functional Dependence Can be generalized to cover the case in which the determining attribute values occur more than once in a table.
  15. 15.  Attribute A determines Attribute B (that is, B is functionally dependent on A) if all of the rows in the table that agree in value for attribute A also agree in value for attribute B.
  16. 16. STUDENT CLASSIFICATIONHOURS COMPLETED CLASSIFICATIONLess than 30 Fr30-59 So60-89 Jr90 or more Sr
  17. 17. STU_HRS STU_CLASS But specific number of hours is not dependent on the classification. In other words, the classification (STU_CLASS) does not determine one and only one value for completed hours (STU_HRS).
  18. 18. Key AttributeAny attribute that is part of a key.Examples:STU_LNAME,STU_FNAME,STU_INIT,STU_PHONE STU_HRS,STU_CLASS
  19. 19. Relational Database KeysSuperkey An attribute (or combination of attributes) that uniquely identifies each entity in a table.
  20. 20. Example:In the STUDENT table..STU_NUMSTU_NUM, STU_LNAMESTU_NUM, STU_LNAME, STU_INIT
  21. 21. Candidate Key A minimal superkey. A superkey that does not contain a subset of attributes that is itself a superkey.
  22. 22. STU_NUM,STU_LNAMEis a superkey, but it is not a candidate key because STU_NUM by itself is a candidate key.
  23. 23. Controlled Redundancy -makes the relational database work. -tables within the database share common attributes that enable the tables to be linked together.
  24. 24. Table Name: PRODUCT Primary Key: PROD_CODE PROD_CODE VEND_CODE Foreign key: PROD_DESCRIPT PROD_PRICE PROD_ON_HA VEND_CODE NDZZXG245Q Steel tape, 12 ft. length 6.79 8 235QER-34256 Sledge hammer, 16-lb. head 18.63 6 231SRE-657UG Rat-tile file 2.99 15 232 Table Name: VENDOR VEND_CODE VEND_CONTACT link VEND_AREACODE VEND_PHONE Primary Key: VEND_CODE 232 Foreign key: none Annalise Crystal 608 224-2134 231 James Johnson 615 123-4536 235 Henry Ortozo 615 899-3425
  25. 25. Primary Key -is usually underlined. - A candidate key selected to uniquely identify all other attribute values in any given row.
  26. 26. Example:VENDOR (VEND_CODE, VEND_CONTACT, VEND_AREACODE, VEND_PHONE)PRODUCT (PROD_CODE, PROD_DESCRIPT, PROD_PRICE, PROD_ON_HAND, VEND_CODE)
  27. 27. Secondary Key - An attribute used strictly for data retrieval purposes.
  28. 28. Example: A customer date are stored in a CUSTOMER table. The customer number is the primary key; the secondary key is the combination of the customer’s last name and phone number.
  29. 29. Foreign Key - An attribute in one table whose values must either match the primary key in another table or be null.
  30. 30. VENDOR VEND_CODE PRODUCT VEND_CONTACT PROD_CODE VEND_AREACODE PROD_DESCRIPT VEND_PHONE PROD_PRICE PROD_ON_HAND VEND_CODE

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