Can I create a dynamic number of inputs during runtime?

Question

Can I create a dynamic number of inputs during runtime?
Oracle 11g
Application Express 4.0.2.00.06
Here is my problem:
We have a table that holds metadata about files (hardcopy or softcopy files).
We expect we may need more columns in the table at some point and don't want to modify the table or the application.
So in order to do this I would like to create:
A table called TBL_FILE with the columns:
TBL_FILE_ID               NUMBER                (This will be the primary key)
TBL_FILE_NAME          VARCHAR2(1000) (This will be the name of the file)
A second table will be called TBL_FILE_META with the columns:
TBL_META_ID               NUMBER               (This will be the primary key)
TBL_FILE_ID               NUMBER                (This will be the forign key to the file table)
TBL_META_COLUMN     VARCHAR2(30)     (This is what the column name would be if it existed in TBL_FILE)
TBL_META_VALUE          VARCHAR2(1000) (This is the value that record and the 'would be' column)
So a person can have as much meta data on the file with out having to add columns to the table.
The problem is how can I allow users to add as much data as they like with out having to re develop the page.
Other things to note is that we would like this to be on a single page.
I know how to add we can create multi-row inserts by using a SQL Query (updateable report),
however the TBL_META_VALUE column in the TBL_FILE_META will sometimes be a select list and other times a text box or number field.
So I don't see now a SQL Query (updateable report) would work for this and I can't create an array of page items at run time can I?
Any idea's how I could accomplish this? Is there a better way of doing this?
Also is there a term or a name for what I am doing by creating these 'virtual' columns in another table?
I found this method when looking at Oracles Workflow tables.

Answer 1

Welcome to the Oracle Forums !
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Can I create a dynamic number of inputs during runtime?
Oracle 11g
Application Express 4.0.2.00.06
Here is my problem:
We have a table that holds metadata about files (hardcopy or softcopy files).
We expect we may need more columns in the table at some point and don't want to modify the table or the application.
So in order to do this I would like to create:
A table called TBL_FILE with the columns:
TBL_FILE_ID NUMBER (This will be the primary key)
TBL_FILE_NAME VARCHAR2(1000) (This will be the name of the file)
A second table will be called TBL_FILE_META with the columns:
TBL_META_ID NUMBER (This will be the primary key)
TBL_FILE_ID NUMBER (This will be the forign key to the file table)
TBL_META_COLUMN VARCHAR2(30) (This is what the column name would be if it existed in TBL_FILE)
TBL_META_VALUE VARCHAR2(1000) (This is the value that record and the 'would be' column)
So a person can have as much meta data on the file with out having to add columns to the table.
The problem is how can I allow users to add as much data as they like with out having to re develop the page.
>
Creating Page Items dynamically is not available. You will have to create excess items and hide/show , etc. But you cannot change the Item Type. All in all, too many limitations in this approach.
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Other things to note is that we would like this to be on a single page.
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The 100 item limit will hit you if you go with extra item on page. With Tabular Form that should not be a limitation, unless you are exceeding the 50 item limit of APEX_APPLICATION.G_Fnn items, and the 60 column limitation of Report region with "Use Generic Column Names (parse query at runtime only)" of Dynamic region.
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I know how to add we can create multi-row inserts by using a SQL Query (updateable report),
however the TBL_META_VALUE column in the TBL_FILE_META will sometimes be a select list and other times a text box or number field.
>
If the type if item is variable it only means you need a way to store the item type. Meta Data of the Meta Data.
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So I don't see now a SQL Query (updateable report) would work for this and I can't create an array of page items at run time can I?
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Yes, you can do it. Updatable report/ Tabular Form query can be constructed from the Meta Data using PL/SQL Function Returning SQL Query . It will be a bit of coding in PL/SQL where you use the Meta Data and the Meta Data of the Meta Data to piece together your SELECT with the right APEX_ITEMs. It might have a performance penalty associated with it, but will not be a serious degradation.
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Any idea's how I could accomplish this? Is there a better way of doing this?
Also is there a term or a name for what I am doing by creating these 'virtual' columns in another table?
I found this method when looking at Oracles Workflow tables.
>
I guess that is just a good TNF. It is the Master-Detail Design Pattern, that sound more modern ? ;)
Regards,