Understanding Semantic Relationships

By Veda C. Storey

CMPT 455/826 - Week 5, Day 1

Sept-Dec 2009 – w5d1 1

Today is full of questions

• While many of them could make good critique items, it is important for all of us to

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Focus

• What is the main concept of this paper

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Focus

• Why is this paper included in the course at this point

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Focus

• How does this paper relate to the other concepts we has studied so far?

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Relationships

• Discuss the differences between– types of semantic relationships– instances of these relationships

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Relationships

• How should we use types of semantic relationships in design?

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Relationships

• How should we use instances of semantic relationships in design?

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Relationships

• Do semantic relationships hold for all instances?

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Relationships

• What are some reasons why semantic relationships should hold for all instances?

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Relationships

• What are some reasons why semantic relationships might not hold for all instances?

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Relationships

• What should we do about semantic relationships that do not hold for all instances?

• How can we work with this?

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Groups of Relationships

• It seems that some of the distinctions made in this paper are somewhat blurred

• (e.g. Member-Group vs Member-Collection)

• Discuss whether or not these blurred distinctions will have a significant effect on the resulting database and whether or not they should be ignored if they cannot be better described

Sept-Dec 2009 – w5d1 13

Groups of Relationships

• The paper identifies a number of types and subtypes of semantic relationships.

– Are they mutually exclusive

– Do they have to be mutually exclusive?

– How can we work with uncertainty in deciding which one to use?

Sept-Dec 2009 – w5d1 14

Groups of Relationships

• In specifying semantics more precisely, there might be a possibility that the semantics might change over time.

• Discuss whether or not changes might occur in the resulting structure and any possible impact they might have

Sept-Dec 2009 – w5d1 15

Groups of Relationships

• While the paper introduces a number of new semantics, it does not propose any way of distinguishing them once they are used to develop an E-R model.

• Discuss the possible problems of losing this information and waht can be done about it.

Sept-Dec 2009 – w5d1 16

Groups of Relationships

• Discuss how the ideas in this paper could lead to identifying even more semantic relationships

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Groups of Relationships

• In various places the paper suggests that some types of semantic relationships do not / might not have a direct impact on the structure of the final database design.

• Discuss whether or not this is true and why the author might say this.

Sept-Dec 2009 – w5d1 18

Individual Relationships

• The paper seems to assume that each term has a single unambiguous meaning – (except for terms like “has”, which it is trying

to replace with more specific terms)

• Discuss the challenges and opportunities involved in dealing with terms that can have multiple meanings.

Sept-Dec 2009 – w5d1 19

Individual Relationships

• The paper deals with inclusion as a unique, exclusive relationship. However there are many types of inclusion which need not be exclusive – (e.g. you can be a student in various classes)

• Discuss the range of inclusions that are possible

Sept-Dec 2009 – w5d1 20

Individual Relationships

• Discuss how “possession” differs from other types of relationships.

• Discuss what some of the unique challenges it introduces for modeling.

Sept-Dec 2009 – w5d1 21

Individual Relationships

• The paper identified the possible existence of similar “sibling” terms, but just recommended choosing one and deleting the other.

• Discuss the problems with ignoring synonyms and suggest a better approach to dealing with them.

Sept-Dec 2009 – w5d1 22

Individual Relationships

• The paper identified “siblings” and “antonyms” as two types of semantic relationships, – but it did not consider that mutually exclusive

siblings might be not be antonyms.

• Discuss how similarities and differences should be dealt with to ensure that all possibilities are covered.

Sept-Dec 2009 – w5d1 23

Individual Relationships

• The paper discusses “antonyms” as 2 separate mutually exclusive relationships.

• Is there a simpler, more straightforward way of dealing with mutually exclusive relationships?

Sept-Dec 2009 – w5d1 24

Individual Relationships

• While the paper discussed some temporal issues, it didn’t go into all possible types of temporal relationships.

• Discuss the range of possible temporal relationships.

Sept-Dec 2009 – w5d1 25

Individual Relationships

• The paper primarily discusses simple relationships, based on a single semantic.

• Discuss the challenges of dealing with relationships that could involve compounds of multiple different semantics (e.g the problem of antonyms).

Sept-Dec 2009 – w5d1 26

Applying this

• While the paper has some potentially interesting ideas, there does not seem to be any strong motivation for developers to make use of them.

• Discuss how and why a developer could be encouraged to make use of these ideas.

Sept-Dec 2009 – w5d1 27

Applying this

• The paper suggests that there are three possible sources of inputs to design:– end users– developers– a design tool (that is designed to help)

• Discuss the strengths and limitations of each.

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