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Difference between revisions of "QUERY"


(Scan query)
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| runtimetype = UBIK.Kernel.Query
 
| runtimetype = UBIK.Kernel.Query
 
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In UBIK, queries are used for fetching a list of [[Contentclass|ContentClasses]] from the database. Queries use data base mechanism for perfomant data access and will deliver a list of objects of a certain [[Metaclass]].
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In UBIK, queries are used for fetching a list of [[ContentClass|ContentClasses]] from the database. Queries use data base mechanism for perfomant data access and will deliver a list of objects of a certain [[Metaclass]].
 
Queries can be used in different scenarios:  
 
Queries can be used in different scenarios:  
 
* data fetching (n records)
 
* data fetching (n records)
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* [[QUERYITEM]]
 
* [[QUERYITEM]]
  
[[Category:Metaclasses]]
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[[Category:Metaclasses|QUERY]]

Revision as of 09:00, 23 July 2015

IC METACLASS.gif Query
Name QUERY
Namespace System.Query
Internal Name SystemObjects.QUERY
TypeString UBIK.Kernel.MetaClass
RuntimeType UBIK.Kernel.Query
Purpose Configure queries
Version 2+

In UBIK, queries are used for fetching a list of ContentClasses from the database. Queries use data base mechanism for perfomant data access and will deliver a list of objects of a certain Metaclass. Queries can be used in different scenarios:

  • data fetching (n records)
  • finding a single or a set of recordset(s)
  • used as definition of root nodes in a View
IC Hint square.pngThere are specific methods available for this type!

Query and QueryItems

A Query is defined for a single MetaClass, where the MetaClass is defined in the property FILTEROBJECT. Once a query is evaluated it will deliver a list of objects of type ContentClasses (instances), filtered as defined by its QueryItems. The correspondence between Queries and its items is created and stored by a relationship SYSREL QUERY. Therefore a single QueryItem can be used several times for different Queries.

Content query

Objects can be loaded on demand from the server, as storing a huge amount of data permanently on the device would need too much resources. A content query is a Query instance classified as SYSCLS QUERY and can be related to other content objects. For being shown in the View hierarchy it is necessary to create a QueryViewItem for the query object itself. Further on, for being published to the client a Query Scopes has to be created and added to the ACM.

The result of the query depends on the network connection and the UBIK® sync mode and follows the same rules as Searching for objects by Optical codes.

Scan query

Objects can be searched by optical codes (e.g. Barcode, QR code) using a scan query.

See detailed articles on How to prepare the object and How to find objects on the client.

Usage of DatabaseViews

It is also possible to define a Database View and use this View for the evaluation of Queries (see VirtualContentClass).

See also