Applied Mathematics for Database Professionals phần 8 doc

... count(*) from DEPT d where d.MGR = r.MGR); CHAPTER 11 ■ IMPLEMENTING DATABASE DESIGNS IN ORACLE 288 7451CH11.qxd 5/15/07 2:26 PM Page 288 where not exists(select 'This employee is assigned as a ... Here is the formal specification of this table constraint: CHAPTER 11 ■ IMPLEMENTING DATABASE DESIGNS IN ORACLE2 68 7451CH11.qxd 5/15/07 2:26 PM Page 2 68 Listing 11-25. Tuple Constr...

Ngày tải lên: 08/08/2014, 18:21

... shorthand name for a given database universe (just symbols) for conven- ience of reference in the text. Database State Database state is a formal term. It is a mathematical construct used to formally ... text. Database Database is an informal term for the actual (business) data that is stored in a computer in a structured way (that is, conforming to the database design). Abstr...

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... you to a formal way of specifying a database via a database state. Formal Representation of a Database State Let’s consider a simple database design involving two table structures: one for employees ... The predicate class (tuple, table, or database) to which a business rule maps is fully dependent on the given database skeleton of the database design. For instance, predicate...

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... 143, 185 , 190–196, 306 for mally specifying transactions and, 225 specifying for sample database design, 186 , 192–196 state transition predicates, 185 , 188 state transition universes, 185 , 190, ... functions, 77 database, 93 database design, 92 database management system (DBMS), 93 database state, 93 database universe, 92 database variable, 92 disjoint sets, 34 function...

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... limit regarding database professionals, then there cannot be a result with an average score of A for database professionals (r egardless of the course), and if ther e is a limit regarding non -database professionals, ... SPECIFYING DATABASE DESIGNS1 48 7451CH07.qxd 5/15/07 9:43 AM Page 1 48 • Database constraints: These are database predicates that you specify inside the d...

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... constraints for our example database design. This definition specifies them by name only. In Listing 8- 8, you’ll find the formal specification for each of these named constraints. ■Note In Listing 8- 7 ... set of database states called the database universe. It holds the admissible database states for the database being specified. You can con- struct a database universe b...

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... of a database; they enable you to extract infor- mation from a database that is relevant for you. • You can formally represent a query as a function over a database universe. For every database ... database: tcrs1 := { (CODE;'AM4DP') , (DESC;&apos ;Applied Mathematics for Database Professionals& apos;) , (CAT;'DSG') , (DUR;5) } For your convenience,...

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... ■ FORMAL DEFINITION OF EXAMPLE DATABASE3 14 7451AppA.qxd 5/15/07 9:45 AM Page 314 Formal Definition of Example Database In this appendix, we deliver the formal specification of the example database ... salary. We hold additional information for all sales representatives in a separate table ( SREP). We hold additional information for employees who no longer work for the company (tha...

Ngày tải lên: 08/08/2014, 18:21