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Advantages and Limitations of using HDBDD to create tables

Hi Folks,

We are planning to develop the objects using HDBDD and trying to understand the limitations in the version we are using Rev 68.

These are the Pros and Cons, we have identified as of now:

Advantages:

1) Version Management

2) Transport Management of the objects via change manager

3) Adding the new columns in the table ( It can be added at any place )

Limitations:

1) Partitioning syntax is not available (

2) Adding the primary key to a table if the table is already created with the field set as "nullable" ( )

So before creating the schema and tables using HDBDD would want to asses if we have missed any potential limitation. So request your help to know the same.

Regards,

Krishna Tangudu

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6 Answers

  • Best Answer
    Posted on Mar 26, 2014 at 06:33 AM

    Hi Krishna,

    Before I proceed, just to clarify your point 3 "Adding the new columns in the table ( It can be added at any place )" - yes columns can be added at any place within the CDS as you are just editing the definition file, but unless you effectively drop the entity (table) by removing entity definition, activate and then restore to rebuild table, any newly added columns will be added to end of table irrespective of position in CDS entity.

    I would also only consider productive CDS with SPS07 - CDS was introduced with SPS06 and no doubt some issues were resolved with introduction of SPS07.

    The CDS gives a wonderfully rich semantic view of your definitions - right click the .HDBDD artifact and select graphical view, especially if associations are implemented (SPS07).

    Coming from an ABAP background I adore the concept of a data dictionary-like central repository, where you can specify types and structures later referred to in entities (tables) for consistency and ease of maintenance.

    Have a go at setting up a few types and entities, change keys, add, remove and change columns (name and type), use those definitions in procedures and attribute views (later consumed by analytic and on to calculation views) for checking of dependencies. I have had issues with dependencies where I have not been able to activate .HDBDD, see . Transport changes from dev to qa and check. Do you need to define entities with spatial-type columns? You cannot (ST_GEOMETRY not recognized as valid type as of 70).

    You are putting all of your "eggs" in one basket. I wouldn't choose to do that with a project of any significant sizing unless a thorough P.O.C. was carried out.

    Hope that helps.

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  • author's profile photo Former Member
    Former Member
    Posted on Aug 07, 2014 at 05:11 AM

    Hi Krishna,

    Good to see the pros and cons of the HDBDD artifact.

    Is there a way to define a default value to a column that is created in the HDBDD table?

    Eg.,

    a column's default value should be the current timestamp.

    Thanks

    Srivatsan

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  • author's profile photo Former Member
    Former Member
    Posted on Aug 10, 2014 at 02:02 AM

    Hi Krishna,

    Here is another limitation. Currently HDBDD does not support TEXT and spatial data types, but will support in the future. Have a look at this thread

    Best regards,

    Wenjun

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  • author's profile photo Former Member
    Former Member
    Posted on Aug 10, 2014 at 02:08 AM

    Another limitation which I found is that there is no "GENERATED ALWAYS AS" in HDBDD or HDBTABLE. However, you can do this when create a table using SQL.

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  • Posted on Aug 10, 2014 at 02:11 AM

    Thanks Wenjun for sharing it here.

    Regards,

    Krishna Tangudu

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  • author's profile photo Former Member
    Former Member
    Posted on Aug 12, 2014 at 05:54 AM

    I have created HDBTI file that loads the CSV file to a HDBDD table but Is it possible to create HDTI for an ordinary table (Created using SQL statement)?

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