EAV modelling approach on database tables and how to use it in Forms Dvl

Question

Hello,
I am dealing with two tables in data modell which are structured on EAV ( Entity-Attribute-Value ) modelling approach.
Survey( Survey# number not null,
Start_Date_Of_Survey date not null ,
End_Date_Of_Survey date null,
Sts_Of_Survey varchar2( 4 ) not null ,
Contractor_Partner# number not null, -- reference foreign key, to Partner's Table
Survey_Report CLOB ) ;
Survey# primary key of Survey.
Meta_Survey_Parameter_Register( Parameter# varchar2( 40 ) not null,
Additional_Parameter_Desc varchar2( 240 ) null,
Type_Of_Value varchar2( 60 ) not null,
Data_Type varchar2( 10 ) not null,
Unit varchar2( 10 ) null,
High_Value varchar2( 20 ) null,
Low_Value varchar2( 20 ) null );
Type_Of_Value Is restricted to : ATOMIC_VALUE, INTERVAL_VALUE_FROM_TO
Data_Type is restricted to: Date, time, number( X,Y ), varchar2,
Unit is varchar2 value not resstricted: for example: %, kg as kilo, m as meter, m/s as meter per second, null
This table is meta table so it suppose to be used as some register - static part of the schema.
Then I have table which attaches Parameters to the Survey as the association table
Survey_Parameters( Survey#, Parameter#, Value, Comment );
Primary key( Survey#, Parameter# );
I need to implement this in Forms and Reports.
My question is how to implement it to maximally make good use of Oracle forms 10g or 11g features and Oracle Reports 10g:
a) when fulfilling the survey and use of parsing rules supplied in Meta_Survey_Parameter_Register
b) at the producing as the survey report with reports
c) in data analyisis in data warehouse impementations.

Answer 1

Hello Craig,
Thank you Craig for your answer.
I must confess that I am also not familiar with EAV theoretical background and concept. Till recently I even did not know that this kind of problem could be placed
in theoretical background called EAV. This put smile nad releive on my mind. Because since this moment I do not feel this kind of problem as some exception or
some exceptional tools or data design ( object modelling and object databases ) suppose to be used. This way I can still counted on concepts in RDBMS databases
and applications. Well I guess so.
Let me comment and answer on your text between your lines.
I am only conceptually familiar with EAV modeling, so I don't claim to be an expert! ;-) Given the abstract way in which data is stored with EAV, I would suggest that you first create a SQL Query that will produce the desired record set.
Ok. But I guess you have in mind to transform vertical set of values to horizontal ( pivoting, transposing )?
View has cast operator that transform data type of each parameter from general ( e.g. varchar2 ) to the one that is registered in the
Meta_Parameter_Register. This way it is provided to get the survey with the list of assigned parameters in horizontal shape?
Once you have this, you can either use the Query as the source of a Database View and then base your Forms data block on this view or you can use the query in a Procedure and base your Forms data block on the procedure or lastely, you could use the query directly and base your Forms data block on the query using the "From Clause" option.
Ok, I think I understand it.
So When I have horizontal list there is challenge during
- insert
- delete
- update
operations how to handle these operations to transform to vertical operation.
This could only be done with Forms data block based on procedure and instead of triggers?
The simplest option would be to create a DB view and base your block on the view. You will not be able to update the data however. If you need to be able to change or add new data, I would suggest you use a Procedure based block. Take a look at these links for additional information on using Procedure and From Clause based blocks.
Ok Craig, sounds like it makes sense.
IT seems your suggestion is caling for some simpler example with the same characteristic of the problem.
Like two tables:
Master( Master#, ..... )
Detail( Master#, Detail#, value_low_or_just_value, value_high, data_type )
Forms: How to base a block on a FROM clause Query
Forms: How to base a data block on a Procedure
Ok,
Hope this helps,
I see your point and it makes sense , it is only the challenge to see how much of flexibility I can reach and how cheap workarounds are to preserve
the level of flexibility in the tools that are not naturally supporting EAV ( like forms and reports ).
If someone's response is helpful or correct, please mark it accordingly.
Sure...
We are on the line.
I am sure there is someone else in the community that experienced this kind of challenge.