help in ER Diagram(CDM)

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help in ER Diagram(CDM)

sun37

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Points: 21
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December 4, 2011 at 10:01 am

#260863

Can anyone help me in this Question .
found the entity type and the constraint , limitation, assumption and diagram
Represent part of the mlitary command structure of the armies of world. It is desired to represent every command unit and all army personnel, along with their ranks and personal details. Each country has one army who has a Commander-In-Chief. Each army is divided into a number of field armies. Each field army has between 90,000 - 200,000 soldiers and is headed by a General. There is only one Field Marshall in each army. Not all generals head a field army.
I think that entity type is :
country
army
field
I think the attribute of countru is the name and the primary key is code >> what you said
country( countryCode, countryName)
so the entity and there attribute but i am not sure it's correct
country : name , code , army name
Army (army name , country name , field army )
- field army : solders number , field army name , army name
- Solders : name , ID , rank
- General : army name , field army name ,
- Marshall : army name , ID , filed army name
- commander – in chief: name ,ID , army name , country name
So please if any one can help me??:crying:

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Devendrakumar SSC-Forever Points: 42493 More actions · Answer 1

Soldier, Marshall, Commander etc. are roles (designations). They are not entities.

I would recommend you to read your Design Notes (assuming it’s a homework question ;-)) before jumping on ERD.

sun37 Grasshopper Points: 21 More actions · Answer 2

Thank you Dev for your comment and explanations is was helpful

thanks :unsure:

sun37 Grasshopper Points: 21 More actions · Answer 3

then the attribute is

Country (country_code, country_name)

Army (army_code, army_name, country_code)

Solders (name, ID, rank, country_code)

Devendrakumar SSC-Forever Points: 42493 More actions · Answer 4

sun37 (12/7/2011)
then the attribute is
Country (country_code, country_name)
Army (army_code, army_name, country_code)
Solders (name, ID, rank, country_code)

Don't you need to connect Army with Soldiers? Think on it... No hurry 🙂

Each field army has between 90,000 - 200,000 soldiers

sun37 Grasshopper Points: 21 More actions · Answer 5

Dev (12/7/2011)
sun37 (12/7/2011)
then the attribute is
Country (country_code, country_name)
Army (army_code, army_name, country_code)
Solders (name, ID, rank, country_code)
Don't you need to connect Army with Soldiers? Think on it... No hurry 🙂
Each field army has between 90,000 - 200,000 soldiers

Don't you think that may be their are more entity named field which is connect to solider

PaulB-TheOneAndOnly SSC Guru Points: 66772 More actions · Answer 6

sun37 (12/7/2011)
Dev (12/7/2011)
sun37 (12/7/2011)
then the attribute is
Country (country_code, country_name)
Army (army_code, army_name, country_code)
Solders (name, ID, rank, country_code)
Don't you need to connect Army with Soldiers? Think on it... No hurry 🙂
Each field army has between 90,000 - 200,000 soldiers
Don't you think that may be their are more entity named field which is connect to solider

if an "army" is composed by "field armies" you are correct but in this case you should have a connection between "army" and "field army", isn't it?

Don't your ER Model shows something like:

(Field Army) BELONG TO (Army)

?

_____________________________________
Pablo (Paul) Berzukov

Author of Understanding Database Administration available at Amazon and other bookstores.

Disclaimer: Advice is provided to the best of my knowledge but no implicit or explicit warranties are provided. Since the advisor explicitly encourages testing any and all suggestions on a test non-production environment advisor should not held liable or responsible for any actions taken based on the given advice.