Tag: virtual warehouse

Denodo – VQL Script To Add A Primary Key to derived Views?

Denodo – VQL Script To Add A Primary Key to derived Views?

Here is a Denodo Virtual Query Language (VQL) code snippet to add a primary key to multiple derived views in Virtual DataPort (VDP).  This code snippet assumes the primary key is the first field in the table.  Useful when needing to do bulk work on data warehouse-style views where the surrogate key of the view is the first field. I have found the script occasionally helpful when working with a large number of views, which need to be updated. VQL To Add A Primary Key On A Semantic Views select ‘ALTER VIEW ‘|| ‘ “‘||View_name||’” ‘|| ‘ADD CONSTRAINT ‘ ||”’PK_’||Column_Name||”’

Continue reading

Technology – When To Cache A Denodo View

Here’s a quick summary of practices about when to use cache when developing denotative views.  These guidelines come from the usual documentation and practical experience and may help you decide whether to cache a view. These are general guidelines, and they should happen the conflict with any guidance you’ve gotten from the Denodo; Please use the advice provided by Denodo. What is a table cache? In denodo, a cache is a database table that contains a result set of a view at the point in time, which is stored in a JDBC database Why Cache? Cache in Denodo can be

Continue reading

Technology – Denodo Supported Business Intelligence (BI) and Reporting Tools

The question of which PI tools to Denodo supports comes up perhaps more often than it should. The question usually comes in the form of a specific intelligence (BI) and reporting tool being asked about. For example, does Denodo support tableau or Cognos, etc. Denodo does provide a list of intelligence (BI) and reporting tools that they support. However, the list of the most commonly used intelligence (BI) and reporting tools. And there is a reason for that, which, basically, boils down to whether or not the intelligence (BI) and reporting tools can use ODBC or has a JDBC driver. 

Continue reading

Technology – Denodo VQL To Get A List Of Cached View Names

Hello, this is a quick code snippet of a Denodo VQL (Denodo Virtual Query Language) to pull a list of cached view names which can be useful in pulling list of cached views. It’s not a complicated thing, but now that I’ve bothered to look it up on putting this note here mostly for me but you may find useful. I have found this useful for several reasons not the least of which is for creating jobs to do maintenance of cached view statistics. Example VQL List Of Cached View Names select name view_name from get_views()        where cache_status <>

Continue reading

Denodo View Performance Best Practice

Since I have been doing more training of beginning users of the Denodo, there have been a lot of questions around performance best practices and optimization. This article is a quick summary of some of the high points of the Donodo documentation, which are typically useful. However, I would like to point out that the performance of Denodo views is: usually, an ongoing process as your environment evolves and that your code changes also, the performance of Denodo views may involve elements be on the Denodo framework itself, such as source system databases and may require some administration configuration and

Continue reading

Denodo – Script To Alter Association Metadata Description

Here is a Denodo Virtual Query Language (VQL) code snippet, which I use to populate the metadata description of Denodo Associations in Virtual DataPort (VDP).  This snippet identifies Denodo Association without a Metadata Description and fills Metadata Description with a simple explanation of what the Denodo Association’s purpose. VQL To Generate Association Alter Statements Description Update select ‘ALTER ASSOCIATION’||’ ‘|| association_name || ‘ ‘||’DESCRIPTION =’|| ””|| ‘Performance association between’ ||’ ‘ || left_view_name || ‘ ‘|| ‘and’ ||’ ‘|| right_view_name ||””||’;’ FROM GET_ASSOCIATIONS() WHERE input_database_name = ‘<<Database_Name>>’ AND input_type = ‘views’ AND len(trim(association_description)) <1 Add a View Name Add this

Continue reading
%%footer%%