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Topic: representing a relationship
topics >
computer science >
information >
access to data
Group:
data
Group:
data structures
Group:
data type
Topic:
attribute-value pairs as information
Topic:
database record
Topic:
data as a named set of data objects
Topic:
fundamental concepts such as type, attributes, relationships are all the same
Topic:
hypertext links
Topic:
kinds of relationships between data
Topic:
knowledge representation
Topic:
network and hierarchical databases
Topic:
recursive data structures
Topic:
relationship as an object
Topic:
roles of a relationship
Topic:
types of hypertext links
Summary
There are many ways to represent a relationship. It can be 1) a data object whose components are the roles of the relation (a tuple), 2) an attribute-value pair, 3) a reference or pointer, 4) the type of a data object, 5) a derived relationship.Because of the multiple ways of representing a relationship, a relationship can also be retrieved in many ways: 1) does it exist, 2) get all matching relationship, 3) get a particular relationship. (cbb 1/90)
Subtopic: join vs. tuple
Quote: the meaning of an IS-A link depends on understanding its nodes [»bracRJ10_1983] Quote: facts can connect any number of things, e.g., John bought a certain computer at Sears [»kentW1_1984] Quote: need to know what a fact connects and why [»kentW1_1984] Quote: relationship needs name and for each role: names, types, and least/most participation [»kentW1_1984] Quote: if a fact connects several things of one type, need to know their roles [»kentW1_1984] Quote: a relationship type (a fact) has a name and a fixed number of things [»kentW1_1984] Quote: a pseudo-record contains one field for each role in a fact [»kentW1_1984]
Subtopic: relation as attribute
Quote: one person's entity is another's relationship; e.g., an airline flight [»coddEF_1990] Quote: the relational model defines relationships in two ways: by symbol matching in joins and by coexistence in a tuple [»kentW_1978] Quote: represent relationships within one thing's record or as a separate record [»kentW_1978] Quote: while relationships typically do not have properties, they may need properties in the future
Subtopic: sentence as relation
Quote: is the arc between a relationship node and an object node also a relationship? [»kentW_1978] Quote: use attributes to express relationships; allows navigational access instead of query access with intermediate objects [»borgA1_1985] Quote: properties are objects which define relations to other objects, e.g., 'works-for' [»zdonSB10_1986] Quote: with context modeling can access all related objects by an attribute [»borgA1_1985]
Subtopic: relation as set
Quote: a sentence is words placed into a relationship with one another; generate 20 sentences from 5 random words [»fishS5_2005]
Subtopic: relation as item
QuoteRef: kayAC6_1968 ;;25 can say John 'is son 'of bill and ask ? 'is son 'of Bill (a set) or John .memberOf. son of bill (true/false). John isn't son of bill undoes the relationship
Subtopic: relation discovery
Quote: L* items contain attributes, relations to other items or sets, and tags (e.g., male) [»grayJC_1973, OK] Quote: Codil items consist of data name, value, and relationship between them, e.g., rela=father Quote: Codil items may be qualified by other items; e.g., rela=father | name=sam [»reynCF11_1971, OK] Quote: RM/T has nonentity associations for relations which are not themselves objects; a single n-ary relation without characteristic entities [»coddEF12_1979] Quote: in RM/T, associative entity types interrelate entities of other types; superordinate role
Subtopic: n-ary relation
Quote: a system should be able to list the relationships for an object or a pair of objects [»kentW_1978]
Quote: a relationship can be one-to-one, one-to-many, or many-to-many [»kentW1_1984] Quote: a relationship direction can map one to one (simple) or one to many (complex) [»kentW_1978] Quote: LP is 1 if complete else 0. MP is 1 if singular, else n. e.g., 1*n for 'at least one' [»kentW1_1984, OK] Quote: CLIENT_ADDRESS_EMPLOYER relation is a combination of RESIDES and EMPLOYED relations; the original relationships and roles are lost [»kentW_1978] Quote: a 3-way relationship is not equivalent to three binary relationships; otherwise generate superfluous non-facts
[»chenPP_1977b]
Group: access to data (12 topics, 307 quotes)
Group: data (140 topics, 3126 quotes)
Group: data structures (12 topics, 278 quotes)
Group: data type (34 topics, 730 quotes)Topic: attribute-value pairs as information (57 items)
Topic: database record (22 items)
Topic: data as a named set of data objects (22 items)
Topic: fundamental concepts such as type, attributes, relationships are all the same (37 items)
Topic: hypertext links (45 items)
Topic: kinds of relationships between data (16 items)
Topic: knowledge representation (41 items)
Topic: network and hierarchical databases (4 items)
Topic: recursive data structures (18 items)
Topic: relationship as an object (6 items)
Topic: roles of a relationship (8 items)
Topic: types of hypertext links
(19 items)