Understanding Semantic Relationships By Veda C. Storey CMPT 455/826 - Week 5, Day 1 Sept-Dec 2009 – w5d11

Today is full of questions While many of them could make good critique items, it is important for all of us to Sept-Dec 2009 – w5d12

Focus What is the main concept of this paper Sept-Dec 2009 – w5d13

Focus Why is this paper included in the course at this point Sept-Dec 2009 – w5d14

Focus How does this paper relate to the other concepts we has studied so far? Sept-Dec 2009 – w5d15

Relationships Discuss the differences between –types of semantic relationships –instances of these relationships Sept-Dec 2009 – w5d16

Relationships How should we use types of semantic relationships in design? Sept-Dec 2009 – w5d17

Relationships How should we use instances of semantic relationships in design? Sept-Dec 2009 – w5d18

Relationships Do semantic relationships hold for all instances? Sept-Dec 2009 – w5d19

Relationships What are some reasons why semantic relationships should hold for all instances? Sept-Dec 2009 – w5d110

Relationships What are some reasons why semantic relationships might not hold for all instances? Sept-Dec 2009 – w5d111

Relationships What should we do about semantic relationships that do not hold for all instances? How can we work with this? Sept-Dec 2009 – w5d112

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 – w5d113

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 – w5d114

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 – w5d115

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 – w5d116

Groups of Relationships Discuss how the ideas in this paper could lead to identifying even more semantic relationships Sept-Dec 2009 – w5d117

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 – w5d118

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 – w5d119

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 – w5d120

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 – w5d121

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 – w5d122

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 – w5d123

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 – w5d124

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 – w5d125

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 – w5d126

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 – w5d127

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. Sept-Dec 2009 – w5d128