nTier structure and linked table

il_dandi · April 30th, 2009, 11:32 AM

I've downloaded great example of Imar Spaanjaar.

http://imar.spaanjaars.com/QuickDocId.aspx?quickdoc=476

I've a problem with linked record...

I create an entityA with records of tableA of the DB and entityB with records of tableB of the DB...

but if 2 tables are link (INNER JOIN in DB) how can I use the records of table2 when I work with an entity of table1??

tableA entityA = new tableA();
entityA = tableAManager.GetItem(id);

how Can I use the fields of entity of tableB in entityA?

Thanks

chroniclemaster1 · April 30th, 2009, 11:03 PM

I don't know the syntax offhand but look up ADO.NET relations. Basically the relationships in your DB get lost when you transfer the data into your dataset, and you have to recreate them in code, ie you have to create the same relationship between entityA and entityB that the two database tables have. Once you do that, they're like one big table and you can grab the information easy.

il_dandi · May 1st, 2009, 05:39 AM

Thanks for your reply!!!

Can you send me an easy example of what I've to do when I've create entities, classDB and classManager ... for manage JOINED fields in my "master entity"

Thanks

il_dandi · May 3rd, 2009, 05:48 PM

I've tried to see the example ... in Contact Person entity I've

/// <summary>
/// Gets or sets a collection of <see cref="Address" /> instances for the contact person.
/// </summary>
public AddressCollection Addresses { get; set; }

/// <summary>
/// Gets or sets a collection of <see cref="PhoneNumber" /> instances for the contact person.
/// </summary>
public PhoneNumberCollection PhoneNumbers { get; set; }

/// <summary>
/// Gets or sets a collection of <see cref="EmailAddress" /> instances for the contact person.
/// </summary>
public EmailAddressCollection EmailAddresses { get; set; }

These are entities linked ... but I would like to know how to read the items of linked entities using something like this

mycontactperson = ConctatManager.Load(ID)...

Thanks

Imar · May 4th, 2009, 03:36 AM

These are just publc properties for to the associated items. Look at the GetItem method of the ContactPersonManager to see how they are filled.

Cheers,

Imar

il_dandi · May 4th, 2009, 03:56 AM

Thanks for your reply! Now I see

but do you confirm me that with this method Can I get also "linked" (with join) fields ...of other tables?

Thanks

Imar · May 4th, 2009, 04:21 AM

You could certainly do that, as long as the query (direct SQL or a stored procedure) returns data that your object model understands....

Imar

il_dandi · May 4th, 2009, 04:36 AM

Yes... this is my problem!!

I don't know if I've to do

1) create a SP with all JOIN and fill a ContactPerson entity where I've added X new proprieties with X fields (the JOINED fields of other tables/entities) that I want to have in my ContactPerson Entity

2) manage the JOINED fields in each entity

Could you send me a simple example?

I hope that you can help me!

Thanks

Imar · May 4th, 2009, 04:43 AM

I'm not sure I understand the question and your two options. Can you elaborate?

Imar

il_dandi · May 4th, 2009, 04:49 AM

I'm a little confused about this :-(((

could you send me a simple example (not a working example) ... I would like only to know the right solution!!

Thanks for help me!