Basics of data handling in Weave
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Selections
The concept of separation of searching and reporting is an important concept in Weave.
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In summary, a central principal in Weave is the entity, which is nothing more than an internal id and a user facing label. A selection is simply a list of identifiers that belong to an entity.
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Spatial Operation
Before spatial operations (select by polygon, zoom to on a map, etc) can be performed against an entity, a spatial engine must be configured telling Weave of the relationship between the layer/table and the entity and a table column (the key column) must be specified to uniquely identify items under each entity. This is done by creating a spatial mapping configuration.
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If you want to display textual attributes for an entity you create data definitions and link those to an entity for display with a data tag (really should come up with a better name for that). Data definitions are a tabular representation of textual data that can come from anywhereany source, but generally will come from a database and be generated by executing SQL, they . They can be used for populating drop down lists, generating content for a BIRT report or most often for direct display of attribute data for the user.
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To allow a data definition to be used to display attribute data related to a selected entity the data tag is used to link an entity to a data definition and provide a label for displaying to the user. This way there can me be more than one set of attribute data that can be displayed to the user for each entity and the user can choose between which attributes to display be selecting the from list of available data's based on the label.
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Attribute display on the client is represented using the data grid view and created using the Data Definition configuration items.
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As a side note, the The spatial identify tool is a short cut shortcut between the previous two items, the spatial mapping and the data definitions, that bypasses the updating of the selection tables and simply takes the list of identifiers returned by the select by polygon operation and uses that list to select the record from the data definition to display back to the user. |
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Beyond the basic data display, generating a Report can allow the user to produce a more formatted form of output beyond just the tabular display of the data. The reports Reports can contain data generated by Weave data definitions, or, reports can pull in data from any data source available to the BIRT reporting engine.
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