Applied Mathematics for Database Professionals phần 4 docx
Applied Mathematics for Database Professionals phần 4 docx
... 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 ... two such tables. Defin-
ition 5 -4 for
mally defines this operator.
CHAPTER 5 ■ TABLES AND DATABASE STATES 107
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Applied Mathematics for Database Professionals phần 3 docx
... two functions be a function.
CHAPTER 4 ■ RELATIONS AND FUNCTIONS 84
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Binary Relations
B
efore we start dealing with binary relations, ... pr
evious
section are reused in this listing.
CHAPTER 4 ■ RELATIONS AND FUNCTIONS 79
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Applied Mathematics for Database Professionals phần 1 pot
... 1995), or visit http://en.wikipedia.org/wiki/
Orthogonality.
xxv
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Applied Mathematics for Database Professionals
Copyright © 2007 by Lex de Haan and Toon Koppelaars
All ...
50
■CONTENTSviii
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Lex de Haan
19 54 2006
“Tall and narrow, with a lot of good stuff on the upper floor”
“A missing value”
745 1FM.q...
Applied Mathematics for Database Professionals phần 2 ppt
... {1,2,3 ,4, 5}
Which of the following expressions are TRUE?
a. 3 ∈ A
b. 3 ⊂ A
c. ∅⊆A
d. ∅∈A
e. {2} ⊂ A
f. {3 ,4} ∈ A
g. {3 ,4} ⊂ A
h. {{3 ,4} } ⊄ A
i. #{{3 ,4} } = 2
CHAPTER 2 ■ SET THEORY: INTRODUCTION42
745 1CH02.qxd ... := {1,2,3}
B := {3 ,4}
Then
A×B = { (1;3), (1 ;4)
, (2;3), (2 ;4)
, (3;3), (3 ;4) }
CHAPTER 2 ■ SET THEORY: INTRODUCTION 39
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See L...
Applied Mathematics for Database Professionals phần 5 pps
... SPECIFYING DATABASE DESIGNS 148
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• Database constraints: These are database predicates that you specify inside the defini-
t
ion of a database universe. The database ... been defined for values of type da
te (see
T
able 2 -4) ,
enabling us to add years to such a value.
CHAPTER 7 ■ SPECIFYING DATABASE DESIGNS1 54
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Applied Mathematics for Database Professionals phần 6 pptx
... 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 by first defining a
database ... result by specifying database predicates. These
database predicates are called
database constraints.
• This formal model is
your—the database professional’s—reference of th...
Applied Mathematics for Database Professionals phần 7 pot
... 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 ... be inserted
into the database:
tcrs1 := { (CODE;'AM4DP')
, (DESC;&apos ;Applied Mathematics for Database Professionals& apos;)
, (CAT;'DSG')
, (DUR;5) }
Fo...
Applied Mathematics for Database Professionals phần 8 doc
... seconds.)
t=3 TX4 is released from block, DI code resumes execution.
t =4 DI code sees 1 042 now manages three departments and the
insert fails.
On t=1, transaction TX4 will start waiting for transaction ... coarse. For instance, if
TX4 were to insert a department
that is managed by someone else (that is, not employee
1 042 ), then TX4 will also block,
whereas it really needn’t in this...
Applied Mathematics for Database Professionals phần 9 pdf
... ■ FORMAL DEFINITION OF EXAMPLE DATABASE3 14
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Formal Definition of Example
Database
In this appendix, we deliver the formal specification of the example database ... tab_EMP )
, ( SREP; tab_SREP )
APPENDIX A ■ FORMAL DEFINITION OF EXAMPLE DATABASE3 24
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The following...
Applied Mathematics for Database Professionals phần 10 doc
... VALUED LOGIC 344
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Numbers
2VL (2-valued logic), 262
3VL (3-valued logic), 262, 340 – 346
4VL (4- valued logic), 341 , 345
symbols
/* */ comments, 144 , 315
A
abbreviating ... execution, 249
order of preference and, 2 54
table constraints and, 265, 268–2 84
triggers, 249 , 267, 300
TRUE value, 340 , 344
truth tables, 4, 11–16
3-valued logic and...
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