Tutorial

[Robert Schwarz]

Error: Magma helper not selected in application configuration.
When I add the WAMagmaConfiguration I see the Magma configuration  
group but I didn't found any drop down menu where I can select WAMagma.

How can I configure my application for the Magma helper?

Robert

Am 28.10.2007 um 06:57 schrieb Keith Hodges:

> There have been calls for a Magma tutorial to go into the Seaside  
> tutorial in the persistency chapter. This chapter already includes  
> Glorp and GOODS.
>
> Just in case someone is already, or thinking of doing this, I have  
> already written such a mini tutorial.
>
> In order to make Magma even easier to use, I have begun rewriting  
> "Magma seaside" to take advantage of my new Seaside Session Helpers  
> interface, which I released yesterday.
>
> The idea being that you can now use Magma, without a specialized  
> Seaside Session class. This should make it easier for users to adopt  
> Magma for their existing applications.
>
> I am a little unsure as to how you are supposed to obtain an exact  
> match of a unique item from the database.
> This is how I would do it (althought I know MagmaCollections dont  
> actually implement #firstOrNil)
>
> ^ (self users where: [ :each | each email = anEmail ]) firstOrNil
>
> Is there a better way to obtain a unique value?
>
> cheers
>
> Keith
>
> p.s. the wiki page that I refer to on MagmaCollections is a bit out  
> of date.
> ----
>
> so far...
>
> Saving all data in an object-oriented database: Magma
>
> Another option to make your data persistent is to use an object- 
> oriented database like Magma.
>
> Installing the Magma Database
>
> Magma is written entirely in Squeak, so there is no need to install  
> a separate server application. Both Magma and Seaside can run in the  
> same image. To install (into a 3.10 based image) just execute the  
> following. (This may take a while)
>
> Installer universes install: 'Magma seasideHelper'.
>
> Configuring your application to use Magma
>
> In the configuration for the 'todo' application you will need to add  
> WAMagmaConfiguration to the configuration "ancestry". Select it from  
> the drop down menu and click "Add". As soon as you do this, a new  
> group of configuration options will appear. You will need to select  
> the "WAMagma", helper class from the drop down menu.
>
> The WAMagma class provides the basic interface between Magma  
> Sessions and Seaside Sessions. Subclasses provide specialised  
> session management such as shared or pooled sessions.
>
> Using Magma
>
> Magma is very easy to use with seaside. To obtain and use a database  
> session helper, simply send #magma to the current session. For  
> example the code "self session magma" will work within all seaside  
> components.
>
> To use Magma in this application in a similar manner to the way we  
> have connected to databases in other examples we need to create an  
> interfacing class, to which we can add our specialized querying  
> methods.
>
> Dictionary subclass: #StMagmaDatabase
>     instanceVariableNames: ''
>     classVariableNames: ''
>     poolDictionaries: ''
>     category: 'STTutTodoApp'
>
> StSession-#initialize
>     super initialize.
>     self db: (self magma rootAs: StMagmaDatabase)
>
> The tutorial application accesses the database via the #db accessor.  
> Here we define this using the #rootAs: helper method, which does  
> everything we need, both to initialize the database, and to provide  
> us the interface that we want to it.
>
> To initialize our users collection we define the initialization on  
> our root object, and we need a method to return the users from the  
> database, to add a new user, and to find a user.
>
> StMagmaDatabase-#initialize
>     | users |
>     users := OrderedCollection new.
>     self at: #users put: users.
>
> StMagmaDatabase-#users
>         ^ self at: #users
>
> StMagmaDatabase-#addUser: newUser
>         ^ self users add: newUser
>
> StMagmaDatabase-#findUserByEmail: anEmail
>     ^ self users
>         detect: [:each | each email = anEmail]
>         ifNone:[]
>
> Notice how for basic usage we have not needed any database specific  
> code! If our userbase is going to grow to a significant size it  
> makes sense to re implement the above using some database features,  
> so we introduce a MagmaCollection which you can read about in detail  
> here: http://wiki.squeak.org/squeak/2639
>
> initialize
>     | users |
>     users := MagmaCollection new.
>     users addIndex: (MaSearchStringIndex attribute: #userName)  
> beAscii.
>     users addIndex: (MaSearchStringIndex attribute: #email) beAscii.
>     self at: #users put: users
>
> StMagmaDatabase-#users
>         ^ self at: #users
>
> StMagmaDatabase-#addUser: newUser
>         ^ self users add: newUser
>
> StMagmaDatabase-#findUserByEmail: anEmail
>     ^ (self users where: [ :each | each email = anEmail ]) firstOrNil
>
> ... need to explain how committing works... etc
>
>
>
>
>
> _______________________________________________
> Magma mailing list
> Magma at lists.squeakfoundation.org
> http://lists.squeakfoundation.org/mailman/listinfo/magma

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.squeakfoundation.org/pipermail/magma/attachments/20071119/b5080a34/attachment.htm