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Life Happens!

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virtual warehouse

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Denodo VQL To Get A List Of Cached View Names

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 <> …

Denodo - Find Views With Missing Metadata Description

Find Views With Missing Metadata Description

Here is a Denodo code snippet, which I use to identify views that do not have the metadata description populated.  Granted, this is a simple thing, but I have found it useful when validating that all Denodo views have been described in Virtual DataPort (VDP). SELECT *FROM GET_VIEWS()WHEREinput_database_name = ‘Database_Name‘And len(description) = 0;

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

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||”’ …

Denodo View Performance Best Practices

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: Avoid ‘Create View From Query’ Using ‘Create view from Query’ to create base views bypasses the denodo optimization engine and pushes directly to the data source as written. Make Sure Primary Keys (PK) And Unique Indexes Have Been Set Accurately …

Technology - Denodo Source Database Permissions For SQL Server

Denodo Source Database Permissions For SQL Server

Denodo does not publish a concise list of what permissions denodo needs in a source database.  So, I thought I would document what is required for a SQL Server data source for denodo. Source database Dendo Access Permissions Assuming there is no need to write back to the source DB, the data source connection permissions in a SQL Server the denodo source database should be: Why Create Table, Not Just Temporary Table? The reason by denodo needs create tables permissions, rather than just create temporary tables permissions, is that temporary tables are only valid for the same connection, and Data …

Denodo – Obtaining The Difference Between Timestamps Or Milliseconds

Obtaining The Difference Between Timestamps Or Microsecond Fields

The topic of how to obtain the difference or duration from timestamps having milliseconds has come up when working in Denodo a few times. So, after having clarified for different developers I thought I’d create this quick reference to clarify the subject little bit. To get the difference with the duration you must subtract the start date field from the in the field (assuming you’re working with the after 1970), and then, divided by the microseconds the time unit in which you wish to display the result. It’s basically boils down to: displaying the resultant milliseconds, no division is required …

Technology - Denodo Security Enforcement

Technology – Denodo Security Enforcement

As the Virtual DataPort Administration Guide, explains in the section “Types of Access Rights” section, on VDP databases, views, rows, and columns. The denodo role-based access mechanism controls how and what a user or user role can use in the virtual layer, including the data catalog. Important Denodo Security Notes Consumer security authorization is imposed at the object level, then Data Level Consumer security authorization is not imposed on Modeling Layers/VDP Folders Using a virtual database to partition projects or subjects is a Best Practice Basically, the ability to grant security is as follows: VDP Database  Permissions grants include connection, …

Script To Alter Association Metadata Descriptions

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 …

Denodo Supported Business Intelligence (BI) and Reporting Tools

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.  …

Technology - When To Cache A Denodo View

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 …