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Messages - A.Russell

Pages: 1 [2]
16
General Board / Deletion Rules -Data Model
« on: June 07, 2007, 12:15:10 am »

Is it possible to set deletion rules to table relationships in a data model? E.g. deny, restrict, cascade...


17
General Board / Re: Database Design Help
« on: April 25, 2007, 05:17:33 am »
Okay, another attempt. Perhaps my confusion was with the primary key? I have now set both the primary and foreign key in the HeadWords table to MemberWords:



Alternatively, would it be better to set an integer ID to each table as index? I would only ever search by word, though.

18
General Board / Re: Database Design Help
« on: April 25, 2007, 03:03:20 am »
I can see why they call it a "head scratcher."

Basically, I am trying to achieve a "one-to-many" relationship with the HeadWords table entries being the "one", and the MemberWords table entries being the "many."

For another example, taken from http://www.vbexplorer.com/VBExplorer/vb_feature/june2000/SQL_for_Beginners.asp


Quote
Name Table

NameID Surname FirstName MiddleName Male AddressId
1 Smith Andrew John true 1
2 Smithe Fred John true 2
3 Wright Anne   false 3
4 Jones Emily Anne false 1
5 Wright David Peter true 3


Address Table

AddressId Line1 Line2 City ZipCode
1 A Street   London  
2 A Road A Town Oxon  
3 A House Village Oxon OX1 3ED


What if someone had more than one address? How would that be expressed?:

1 Smith Andrew John true 1,2   ???

And how would that look modelled visually in EA?


In the case I am attempting with my dictionary, I have used the words themselves as their identifiers. Should I replace them with an integer ID? I think this is called an "artificial key."

The relationship would be "P Cardinality" since one headword can have one or more memberwords: Example:

Headword: Air

Memberwords:
Air
Airy
Airier
Airiest
Airiness
Airily
Airless
Airs
Aired
Airing
Airings
Midair

Most of the time, the data would be searched by MemberWord. The HeadWord contains most of the interesting data, like what level it appears in in different graded lists.

19
General Board / Re: Database Design Help
« on: April 20, 2007, 05:33:45 am »
I live in Japan. I ordered a book in English from Amazon, but it will take some time to arrive. In the meantime I've been scouring the web and asked on this notice board.

I tried:
play plays \N \N 3
play playing \N 5 2
poo poos 3 \N 4

Though that would be a duplicate pk entry, and it didn't work anyway. When attempting to load it into the database it simply skipped that line. I can't set it as a foreign key either.

If I were programming, I would do something like:

ptrToMemberwordTable pMemberWords[]


However, there aren't any arrays. I've searched for an example, but haven't managed to find one.


20
General Board / Re: Database Design Help
« on: April 19, 2007, 11:30:39 pm »
I have tried it, and I think it's okay. Lacking experience in this, though. How does this look:

Quote
DROP TABLE IF EXISTS HeadWords
;
CREATE TABLE HeadWords
(

HeadWord VARCHAR(32) NOT NULL,

MemberWord VARCHAR(32),

lBNC SMALLINT,

lGSL SMALLINT,

lAWL SMALLINT,

PRIMARY KEY (HeadWord)
)
;
LOAD DATA LOCAL INFILE 'C:\\DatabaseSchema\\data_HeadWords.txt' INTO TABLE HeadWords LINES TERMINATED BY '\r\n';

///data_HeadWords.txt'
play      plays      \N      \N      3
      playing      \N      5      2
poo      poos      3      \N      4


DROP TABLE IF EXISTS MemberWords
;
CREATE TABLE MemberWords
(

MemberWord VARCHAR(32) NOT NULL,

HeadWord VARCHAR(32),

PRIMARY KEY (MemberWord)
)
;
LOAD DATA LOCAL INFILE 'C:\\DatabaseSchema\\data_MemberWords.txt' INTO TABLE MemberWords LINES TERMINATED BY '\r\n';


///data_MemberWords.txt'
plays      play
playing      play
poos      poo



Quote
///Results

Headword table:

  HeadWord  MemberWord  lBNC  lGSL  lAWL  
      play plays NULL NULL 3
        playing NULL 5 2
      poo poos 3 NULL 4

Memberword table:

  MemberWord  HeadWord  
      plays play
      playing play
      poos poo


When inserting multiple memberwords into the HeadWords tables, is it correct that there is an empty space for the primary key?

21
General Board / Re: Database Design Help
« on: April 19, 2007, 09:07:45 pm »
Thank you. I changed my model as suggested. Would this create the appropriate schema?:


22
General Board / Database Design Help
« on: April 19, 2007, 01:34:39 am »
I am new to database modeling and was hoping someone could help me.

I want to create a database that stores information about words, a little bit like a dictionary.

Each word (memberword) has a headword. e.g. is -> be (headword). Headwords can have multiple memberwords. e.g. be -> is, was...

Thge confusing part for me is how to have multiple memberwords. Here is what I have so far:



This doesn't reflect that a headword can have multiple memberwords. How is this done?



23
General Board / Re: Set Datatype for Table Column
« on: April 18, 2007, 11:54:16 pm »
Yes, making sure to set the database type as well as the stereotype does the trick. Not very intuitive, though.

I'll report it.


24
General Board / Re: Set Datatype for Table Column
« on: April 18, 2007, 08:12:58 pm »
I've been experimenting, and I think it might be a bug.

From the toolbox, if I drag a Class onto the diagram and set its stereotype to table there will be no data types in the drop down box when trying to add attributes. However, if I drag a Table over, which already has its stereotype set, then the data types show.


25
General Board / Set Datatype for Table Column
« on: April 18, 2007, 06:29:26 pm »
In Data Model, how can you set the datatype for a column? The Data Type pulldown menu is empty.

I am using Enterprise Architect 6.1.792




26
Bugs and Issues / Kanban Diagram Doesn't Show Element Properties
« on: August 27, 2014, 09:15:08 am »
Elements on a Kanban don't show any properties, like notes, despite being set in Diagram Properties.

When an element is created, the properties show for a moment, then disappear.  

27
Uml Process / Re: Modeling Risk Analysis
« on: August 16, 2007, 06:06:47 pm »
Since assessing and mitigating risk early is one of the tenets of a Rational Unified Process I thought someone might have some ideas.

What I have done is created a special folder for risk assesment and used Issues to note risks and their mitigation. I then added links to them from the use cases or requirements that they concern.

The only problem with that is how to incorporate them into the project estimate.

Anyway, I just thought I'd share that. If anyone has any better ideas, I'd like to hear them.

28
Uml Process / Modeling Risk Analysis
« on: August 04, 2007, 01:23:52 am »
Does anyone have any best practices concerning modeling risk analysis with uml? I can't find a good example.

I can see that risks can be noted in the Project window for individual elements, and that a metric can be assigned in Project Indicators. What is really needed is somewhere all the risks can be viewed and ranked. Does anyone have a good method of managing this?

Furthermore, is it possible for this documentation to be discluded from reports.



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