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How can I verify if Denodo is really using Association for my query

Hi team - just want to check if Denodo's execution trace (or anything else) will show me an association if it gets used while executing a query (on the views on which this association is defined) ? How can I ensure that association is getting used for my queries ?
user
26-07-2020 07:48:43 -0400

1 Answer

Hi, An association represents a relationship between two views. The association for a view is useful in Query optimization techniques like aggregation pushdown. This would reduce execution times and avoids the movement of big amounts of data through the network. I will refer to the section [Why You Should Define Associations Between Views?](https://community.denodo.com/docs/html/browse/7.0/vdp/administration/restful_architecture/associations/associations#why-you-should-define-associations-between-views) of Virtual DataPort Administration Guide for more information. If I want to discover the associations of a single JDBC base view, I would open the view and click Associations, then click Discover. And also, I can navigate through associations using navigation queries (SELECT_NAVIGATIONAL) or the RESTful Web service. Additionally, I can get the information about all the associations, or the associations in which a view is involved, or the associations published by a web service by using the stored procedure [GET_ASSOCIATIONS](https://community.denodo.com/docs/html/browse/7.0/vdp/vql/stored_procedures/predefined_stored_procedures/get_associations#get-associations). You can have a look at the section Declaring Primary Keys and Associations of the knowledge base article [Denodo Query Optimizations for the Logical Data Warehouse](https://community.denodo.com/kb/view/document/Denodo%20Query%20Optimizations%20for%20the%20Logical%20Data%20Warehouse?category=Performance+%26+Optimization) and also to the section [Associations](https://community.denodo.com/docs/html/browse/7.0/vdp/vql/restful_architecture/restful_architecture#associations) of the virtual DataPort VQL Guide for more information. Hope this helps!
Denodo Team
27-07-2020 08:29:13 -0400
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