Understanding Update Maps
This page last changed on Nov 29, 2008.
Oracle Data Service Integrator Documentation > Data Services Developer's Guide Understanding Update MapsAn update map allows you to easily update your logical entity data service without having to write Java or XQSE code. This overview provides a foundation for understanding what an update map is and how you can use one.
Oracle Data Service Integrator generates a default update map automatically when you create a logical entity data service with a primary read function. You can see the update map associated with a data service by clicking the "Update Map" tab at the bottom of the screen (see the example that follows; click to enlarge image).
Example: a simple update map An update map procedure is a create, update, or delete procedure that is implemented by an update map. The update map maps values from the input to the update map procedure to the inputs of the procedures in the underlying data services. These underlying data services that the logical entity data service is composed of are referred to as the source data services. In the previous example, the input is mapped to the two source data services CUSTOMER and ORDERS. The blue arrows in the update map show how the values are mapped. A logical entity data service has a target type that describes the entity that the data service is about. All read functions in the data service must return instances of the target type and all update map procedures must accept instances of the target type as input. For example, say that we have an entity data service about customers. The read functions of this data service must return customers and update map procedures must take customers as input. The Target BoxThe target box displays the data type of the input to the update map procedures and the procedure icons. There is always exactly one target block in an update map and it is displayed on the right. Example: the target box
The input type Procedure icons For Each BlocksA for each block loops over elements in the input to the update map procedure. A for each block is associated with a variable and a path expression. The path expression defines the sequence to iterate over and the variable binds to elements in the sequence. The variable may be referenced by expressions inside the for each block. Example: for each blocks
Update BlocksAn update block invokes the primary create, update, or delete procedure of a source data service. It will invoke a procedure every iteration of the for each block that contains it. The contents of the update block represent the type of the input given to the procedure. Each element and attribute in the update block is assigned a mapping expression that determines what its value will be when the procedure is invoked. You can select an element or attribute to view or change the expression that determines what value it receives when the procedure is invoked (see the example below). Procedure icons Output variable Condition Dependencies Disabling an update block Example: update blocks
The Return Key BlockThe key block describes what will be returned by the update map create procedure. If the data service does not have a key specified, then there will not be a key block and there will never be more than one key block for an update map. Example: the return key block
CustomizationOracle Data Service Integrator generates a default update map automatically when you create a logical entity data service with a primary read function. This default update map is generated based on the primary read function of the data service. As you change the primary read function, the update map will be regenerated automatically. There are several ways to customize an update map. See the following topics for more information: Example Clicking the Customized icon and choosing View Customization from the menu displays a dialog showing the current customizations to the update map, including the enabling of update blocks, any conditions that have been set, and any changes to the mappings. This can help you to identify potential problems with the update map that might occur after you make a change to the primary read function, for example. If a problem has been identified, clicking OK accepts the correction and generates a new update map. Note that in previous versions of Oracle Data Service Integrator, customizing the update map and then changing the primary read function resulted in the update map no longer being automatically regenerated. In the current version of Oracle Data Service Integrator, the update map is updated incrementally after customizations, as required.
Customer Orders Update Map.png (image/png)
The Target Box.png (image/png) Hover Over Procedure Icon.png (image/png) Red Update.png (image/png) Yellow Update.png (image/png) Green Update.png (image/png) Green Delete.png (image/png) Green Create.png (image/png) For Each Blocks.png (image/png) Update Blocks.png (image/png) The Return Key Block.png (image/png) Update Block Element.png (image/png) Customize.png (image/png) cust.png (image/png) |
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