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QuoteRef: kentW1_1984

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ThesaHelp:
references i-l
Topic:
fact-based analysis for database design
Topic:
facts as relationships between entities
Topic:
hypertext links
Topic:
representing a relationship
Topic:
roles of a relationship
Topic:
entities
Topic:
data as a named set of data objects
Topic:
information as facts
Topic:
type inheritance as reuse
Topic:
unique names
Topic:
symbolic representation
Topic:
using a description as a name
Topic:
unique numeric names as surrogates
Topic:
names defined by context
Topic:
data type by lexical constraints
Topic:
objects without names
Topic:
naming by pointing or recognition
Topic:
alias names
Topic:
renaming
Topic:
database record
Topic:
value as an abstraction
Topic:
existence of database entities
Topic:
database entities
Topic:
type hierarchy
Topic:
database keys and indexing

Reference

Kent, W., "Fact-based data analysis and design", Journal of Systems and Software, 4, 1, pp. 99-121, 1984. Google

Quotations
abstract ;;Quote: to design a database, should focus on facts to be maintained by the database
102 ;;Quote: first identify facts to be maintained and then aggregate facts into data records
102 ;;Quote: all facts are connections between things instead of attributes or relationships
103 ;;Quote: facts can connect any number of things, e.g., John bought a certain computer at Sears
103 ;;Quote: need to know what a fact connects and why
103 ;;Quote: if a fact connects several things of one type, need to know their roles
104 ;;Quote: an entity is anything which a noun or noun phrase can reference
104 ;;Quote: a subtype inherits the properties and facts of its parent type
104 ;;Quote: a relationship type (a fact) has a name and a fixed number of things
104 ;;Quote: a relationship can be one-to-one, one-to-many, or many-to-many
106 ;;Quote: an ideal representation gives every entity a unique symbol that acts as its surrogate
106 ;;Quote: a symbol or representation is any character string that stands for something, e.g., 'six feet'
106 ;;Quote: most entities do not have unique names, need a descriptive phrase such as employee 999999
106 ;;Quote: a number represents an entity if we know the symbol type, i.e., naming universe
107 ;;Quote: a symbol type is the lexical constraints on allowable strings
108 ;;Quote: some entities have no representation; derived from a representation or a related entity
108 ;;Quote: some entities are only known via a related entity, e.g., the 1980 election
108 ;;Quote: representation of some entities derived from context, e.g., the name of the home team
109 ;;Quote: refer to most things by a combination of pointing, noun phrases, and context
109 ;;Quote: a representation is complete if there is one for every member of a type, otherwise are facts
109 ;;Quote: nonunique representations commonly occur in data; discriminated by local conventions
109 ;;Quote: uniqueness is required when an agent can't otherwise distinguish objects
109 ;;Quote: if multiple representations then problems of existence testing, multiple participation
109+ ;;Quote: a singular representation avoids multiple representations for an entity
110 ;;Quote: a representation, such as names, should be stable due to cost of renaming
110 ;;Quote: LP is 1 if complete else 0. MP is 1 if singular, else n. e.g., 1*n for 'at least one'
111 ;;Quote: records can not correspond to major entities; what are they, drifting assignment, relationships vs. attributes
111 ;;Quote: lengths, colors etc. can occur in a database without existence being announced
111 ;;Quote: need database mechanism to announce the existence of an entity
111+ ;;Quote: database entities which exist, will have single-valued facts associated with them
112 ;;Quote: for each fact specify an identifier, a relationship name, entity type for each role (if necessary), least and most participations
113 ;;Quote: relationship needs name and for each role: names, types, and least/most participation
113 ;;Quote: a entity type has a name, super type or symbol type
113 ;;Quote: a pseudo-record contains one field for each role in a fact
113 ;;Quote: in a pseudo-record, actual entities (e.g., employees) sit in fields of the record
113 ;;Quote: initially, pseudo-records do not contain digital data and there is one record for each attribute of an entity
114 ;;Quote: employee numbers are good representations for entities
114 ;;Quote: a pseudo-key is a set of fields that uniquely identifies a record
114 ;;Quote: merge pseudo-records when they have compatible keys
114 ;;Quote: if a pseudo-record key allows zero participation, it can merge by padding with null values
115 ;;Quote: in merging compound keys should only merge attributes of the same relationship
116 ;;Quote: soft keys can be null; merging soft keys propagates softness to all keys
116 ;;Quote: when possible, a data record should aggregate all facts about an entity
117 ;;Quote: need to eliminate nonsymbol fields from pseudo-records to make them proper records
119 ;;Quote: in fact-based analysis, start with facts instead of entities; do not need to distinguish relationship from attribute
119 ;;Quote: instead of normalizing badly assembled records, should construct normalized records directly


Related Topics up

ThesaHelp: references i-l (342 items)
Topic: fact-based analysis for database design (15 items)
Topic: facts as relationships between entities (22 items)
Topic: hypertext links (45 items)
Topic: representing a relationship (28 items)
Topic: roles of a relationship (8 items)
Topic: entities (20 items)
Topic: data as a named set of data objects (22 items)
Topic: information as facts (21 items)
Topic: type inheritance as reuse (27 items)
Topic: unique names (58 items)
Topic: symbolic representation (26 items)
Topic: using a description as a name (21 items)
Topic: unique numeric names as surrogates (67 items)
Topic: names defined by context (36 items)
Topic: data type by lexical constraints (15 items)
Topic: objects without names (7 items)
Topic: naming by pointing or recognition (13 items)
Topic: alias names (39 items)
Topic: renaming (10 items)
Topic: database record (22 items)
Topic: value as an abstraction (25 items)
Topic: existence of database entities (19 items)
Topic: database entities (12 items)
Topic: type hierarchy (18 items)
Topic: database keys and indexing (18 items)

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