Together the QueryManager bean and the Query
object provide data source services to the presentation beans and the dimension list beans.
The QueryManager bean and the Query
object assist users by providing the following kinds of data services:
Database support
Data interfaces
Support for the development of queries
The QueryManager bean can support multiple Query
objects. QueryManager has a MetadataManager
property that is set with a reference to a MetadataManager bean. Through this reference, the QueryManager provides database services to all the Query
objects that it supports.
Each Query
object has a QueryManager
property that contains a reference to the QueryManager that supports it.
The Query object implements the following interfaces for its interactions with other objects.
oracle.dss.util.DataSource
-- Used by beans that extend the oracle.dss.dataView.DataView interface. These beans include: Crosstab, Graph, and Table. The following beans also have the option of using this interface: DimensionList, DimensionCombo, DimensionListPanel, and DimensionListDialog.
oracle.dss.datautil.LayoutContext
-- Used by LayoutPanel objects that can be used with QueryBuilder.
oracle.dss.util.QueryContext
-- Used by QueryBuilder, DimensionList, DimensionCombo, DimensionListPanel, and DimensionListDialog beans.
oracle.dss.thin.beans.ThinBean
-- Used by Beans that extend the oracle.dss.thin.beans.ThinBeanUI
interface. These beans include ThinCrosstab, ThinGraph, ThinTable, and other thin beans.
The following list provides a brief description of how each data interface is used:
DataSource
-- Provides objects that implement DataAccess
and DataDirector
. The DataAccess
methods provide for data retrieval and the DataDirector
methods provide for data manipulation such as drilling and pivoting.
LayoutContext
-- Provides LayoutAccess
objects that let layout panels obtain a DataDirector
and a DataAccess
in order to manipulate a copy of the original layout of a Query
object.
QueryContext
-- Provides QueryAccess
objects that allow applications to manipulate a copy of the original Query
object.
ThinBean
-- Provides methods so that applications can perform state management on the Query
object.
Methods of the Query
object make the query and calculation capabilities of the OLAP API accessible to any application that wants to develop queries.
Within BI Beans, QueryBuilder and CalcBuilder define queries by developing selections that consists of steps. The Query
object evaluates each step of a query or a calculation and translates it into OLAP API calls.
If an application wants to develop queries at runtime without using QueryBuilder, then the application must create selections programmatically and apply these selections to the Query object.
Characteristics of the Query Object
Characteristics of the QueryManager Bean
Creating Selections Programmatically
Managing State in an HTML-Client Application