Re: Display database content on a page
Re: Display database content on a page
- Subject: Re: Display database content on a page
- From: André Rothe <email@hidden>
- Date: Mon, 9 Oct 2017 09:31:43 +0200
Thank you for your responses! I have read the book, things are clearer
now. I will come back with further questions about locking and long
running requests...
Best regards
Andre
On 07.10.2017 16:14, Markus Ruggiero wrote:
> Andre,
>
> please take this seriously
>
> Chick Hill wrote:
>
>> And it will also show you the correct and effective way to leverage WO
>> and Wonder. The architecture is quite different from most other
>> frameworks and if you don’t make the adjustment to that, you will be
>> forever struggling against the intention of the frameworks.
>
> One important thing to note (and this seems to be a major stumbling
> block for all non-WOers): We are programming objectoriented, we are not
> programming SQL / database stuff!!
>
> When you think "OO" you think "object". An object encapsulates state and
> shows behavior. When you start to learn oo-programming you usually have
> instance variables and methods. The object's state is kept in the
> instance vars and the behavior is defined by the methods. It is good and
> strongly recommended style to make instance variables private (or maybe
> proteced) and create public accessors (getter and setter methods). One
> should never access an object's state directly (instance variables) from
> outside the object but access them through the getter and setter
> methods. This allows the object (actually the programmer writing the
> class) to re-implement the internal representation of state in any way
> that makes sense. Any piece of code using the getter/setter methods
> won't be affected by that.
>
> The EOF allows you to implement objects in a way so that their internal
> state is not kept in instance variables but is connected to a database
> record. Correct oo-thinking says "I access the object's state via
> accessor methods. I don't care where/how the object manages to store
> that state". Your enterprise objects are based on classes that inherit
> from framework classes. There is functionality in those classes to
> pull/push state to/from a relational database. You as the "user" of the
> object DO NOT CARE! The EOF framework manages this for you.
>
> You MUST NOT THINK "database/table/record" but THINK "OBJECT".
>
> Instead of asking "how do I retrieve customer records from the
> database?" you should think "how do I make the framework give me a list
> of customer objects that have their state backed by a record in the
> database?". With this in mind EOF becomes almost trivial to use. Any
> programmer coming from "standard java" background has a problem with
> this thinking because most persistence frameworks are more or less
> nicely built "sql generators". Thus one's thinking is often closer to
> "data record" instead of "object". Not so with Wonder and EOF. Just
> think "object" and you are all set.
>
> With the EOModel you basically tell the EOF framework how to "map object
> thinking into a relational database". Let the framework do it, you are
> an oo-programmer!
>
> Hope this clears things a bit.
>
> Have fun
> ---markus---
>
>
>> On 6 Oct 2017, at 16:38, André Rothe <email@hidden
>> <mailto:email@hidden>> wrote:
>>
>> Hi Markus,
>>
>> I'm on part C of the book...
>>
>> Best regards
>> Andre
>>
>> On 06.10.2017 15:51, Markus Ruggiero wrote:
>>> Hi Andre,
>>>
>>> I am the author of Learning the Wonders. If you have any question
>>> regarding the book you can reach me here or directly by writing to
>>> email@hidden <mailto:email@hidden>
>>> <mailto:email@hidden>.
>>> I'll be glad to help you get started.
>>>
>>> ---markus---
>>>
>>> PS
>>> Chuck and Theo, thanks for the recommendation :-)))
>>> Yes, I use the book as official coursebook in formal education in
>>> Switzerland for the module "Object Oriented implementation of Multiuser
>>> Applications". This in itself has nothing to do with Wonder but
>>> everything with oo-concepts and I use Wonder/WebObjecs as a showcase for
>>> clean oo design.
>>>
>>>
>>>> On 5 Oct 2017, at 23:12, Theodore Petrosky <email@hidden
>>>> <mailto:email@hidden>
>>>> <mailto:email@hidden>> wrote:
>>>>
>>>> "Learning the Wonders" is the best book to start with. The author uses
>>>> that book in classes he teaches (I believe in Germany).
>>>>
>>>> I would recommend that book to start with over the others that are
>>>> available.
>>>>
>>>> All of the videos are available in the iTunes podcasts. I know the
>>>> other links sometimes don’t work.
>>>>
>>>> Use the iTunes podcasts. go to podcasts, then select Store, then
>>>> search for WebObjects.
>>>>
>>>> I know you mentioned that you viewed the two chapters of Leaning the
>>>> Wonders. It really gets going after that.
>>>>
>>>> Ted
>>>>
>>>>
>>>>
>>>>> On Oct 5, 2017, at 3:31 PM, Chuck Hill <email@hidden
>>>>> <mailto:email@hidden>
>>>>> <mailto:email@hidden>> wrote:
>>>>>
>>>>> Here is a good place to start:
>>>>>
>>>>> https://www.amazon.com/Learning-Wonders-Markus-Ruggiero-ebook/dp/B00FCDHDAA
>>>>> http://learningthewonders.com
>>>>>
>>>>>
>>>>> Chuck
>>>>>
>>>>> On 2017-10-05, 12:25 PM, "Webobjects-dev on behalf of André Rothe"
>>>>> <webobjects-dev-bounces+chill=email@hidden on behalf
>>>>> of email@hidden> wrote:
>>>>>
>>>>> Am 2017-10-05 20:10, schrieb Theodore Petrosky:
>>>>>> You are working too hard!!!!!
>>>>>
>>>>> :-)
>>>>>
>>>>>> you need to look at all the examples. what you are asking for is so
>>>>>> simple (when you know how).
>>>>>
>>>>> LOL, exact. When you know how and where... The problem is, that a
>>>>> lot of
>>>>> WebObjects links on the internet are dead.
>>>>>
>>>>>> Have you used EOModeler to build your model?
>>>>>
>>>>> Yes, I have.
>>>>>
>>>>>> I recommend you look at these videos:
>>>>>
>>>>> 50% of these videos I have already watched (and downloaded). A lot
>>>>> things you don't understand at the first time you will watch the
>>>>> video,
>>>>> because the WO community has its own "language", so it is hard to
>>>>> follow
>>>>> the concepts.
>>>>>
>>>>> Nevertheless, I have downloaded the examples for the WebObjects
>>>>> Developer's Guide. This book is not bad, but it doesn't summarize the
>>>>> workflows. So I have to read all the pages to find a hint for a
>>>>> specific
>>>>> problem. That is also a problem to find something, if you cannot name
>>>>> the problem with the correct "WO Community term".
>>>>>
>>>>> My question refers to WOTable. In the meantime I have decompiled
>>>>> WORepetition and find out, that you have to set components into the
>>>>> WOTable tags, one component for every column of the database table,
>>>>> which I need. The output of WOTable base on the "list" attribute,
>>>>> which
>>>>> needs an NSArray or List and the "item" attribute, which is of the
>>>>> type
>>>>> of the underlying database table.
>>>>>
>>>>> As I sent my question, I thought, that WOTable creates output for all
>>>>> attributes of the "item" automatically, so I tried to reduce the
>>>>> attributes of "item" before it will be visible to WOTable. But that
>>>>> was
>>>>> a fault.
>>>>>
>>>>> Sorry for my "simple" questions, but this is a learning process. And
>>>>> there are almost 20 years between my knowlegde of WebObjects and the
>>>>> knowledge of the other readers here.
>>>>>
>>>>> Best regards
>>>>> Andre
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>>>>
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>>
>> --
>> UNIVERSITÄT LEIPZIG
>> Medizinische Fakultät
>> Zentrum für Klinische Studien Leipzig – KKS
>> André Rothe
>> CIO
>> Härtelstr. 16-18, 04107 Leipzig
>>
>> Tel: 0341/ 97 16118
>> Fax: 0341/ 97 16189
>> WWW: http://www.zks.uni-leipzig.de
>>
>
--
UNIVERSITÄT LEIPZIG
Medizinische Fakultät
Zentrum für Klinische Studien Leipzig – KKS
André Rothe
CIO
Härtelstr. 16-18, 04107 Leipzig
Tel: 0341/ 97 16118
Fax: 0341/ 97 16189
WWW: http://www.zks.uni-leipzig.de
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