Querying Sys tables - Calculation Views

[#1]

Soooo....

I've been playing around in the system views and found quite a bit of useful stuff for querying meta-data around base objects.

For Tables, column definitions, constraints etc ...

For Attribute views,  column names, dependencies, joins & join conditions....

Yet for Calculation Views; I'm drawing a blank.

Ok, so I can list them (name, type) from sys.objects, but I've not been able to gain any further info.

Does anyone know (a) why this is (they they are not detailed in sys views ?)  and (b) does the data I'm looking for exist in tables elsewhere ?

Just for illustration, a small example of the views I've been hitting so far ..

M_TABLES

CS_VIEW_COLUMNS

CS_BO_VIEWS

CONSTRAINTS

CS_JOIN_TABLES

CS_JOIN_PATHS

CS_JOIN_CONDITIONS

CS_KEY_FIGURES

OBJECTS

OBJECT_DEPENDENCIES

[Former Member]

Hi Lars, Simon

I'm relatively new to the HANA world, so forgive me if I am asking stupid questions, but I don't quite follow about the mappings.

When I open up a Calculation View in HANA Studio, I can drill down to see which Tables (and Fields) it is based upon.  When I create a new Calculation View that is based upon a SAP Table, for example, I can choose which Table Fields are to be included.  Why can't I get to that in the metadata?

[lbreddemann]

A major theme in SAP HANA models is that you stack them massively.

It's not uncommon to have one calc view calling tens of other calc views, analytic views and tables just for one model.

Now imagine to know that you have a specific column and you want to change this column.

You would need to know all direct and indirect uses of that column in all models.

This would also include usage of calculated columns that are then further used.

This kind of information is not stored anywhere in the system with regards to the underlying tables, but always only as a reference to the next view/table.

So, yes, as long as you are in a very simple model, all is good and easy.

Unfortunately things are not that simple (yet... )

[Former Member]

I hear you, however.....

this is all we are aksing for :

"a reference to the next view/table"

Somewhere under the hood, HANA knows that (in my design);  table_1 field_1 is used in view_32 field_9.

And it will also know that view_32, field_9 is used in view_1032 field_3.

The quesion is, if HANA knows that, why can't we extract that information ?

There maybe a good and logic; reason why .... we just don't understand what that reason is !

[lbreddemann]

Well the "reason" here is a purely technical one.

The dependencies for the information models are stored in the definition of those models only and not in a central table.

For the processing of those views it's simply not necessary to have that on column level.

Another point here is that you'd also have to consider design time dependencies (e.g. non-active views) to be complete.

Anyhow, I'd say there is currently no architectural-special-HANA-related reason.

It's simply a functionality that is not there (yet?).

I'd assume if enough customer demand for something like this is present then product development will look into including that.

[former_member182302]

+1 for this Idea of including this feature. Even in the current assignment of mine where multiple teams work on the same hana box for different projects and documentation being one of the things often neglected it leads to creation of the as-of document for which we would need this kind of feature.

I think its time, we need to add it in the Idea Place and get votes there.

Regards,

Krishna Tangudu

[Former Member]

Thanks to both Krishna and Nicholas, for reassuring me that I am not after all mad nor alone in this thought.

I have not yet looked into 'Ideas Place';  but it seems that I will have to go and explore.

(thanks for the tip Krishna).

Bear with me, once I find some quiet time to write all this up 'properly' I can drop a note on here with a link.

(unless any of you are impatient and beat me to it   )