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Application Developer's Guide
Developing an application : Using a sample application to demonstrate application development : Using dataslots to define the information flow : Using dataslots in the process template
Using dataslots in the process template
Specify the initial/default value of a dataslot at definition time. You have the option to set a:
*Static value; that is, a value that is displayed for each instance of the process. For example, entering "Carl" as the value for the Assignee dataslot results in Carl being the Assignee for each process instance; or
*Dynamic value, by entering a dataslot name, preceded by the @ symbol, that displays the value of the designated dataslot at run time. In this case, entering "@Creator" as the value for the Assignee dataslot means that the person who created the instance is the assignee and this value can change from instance to instance and can reflect changes made at run time.
When the dataslot value is set, many other worksteps are free to access this value. In this manner, dataslots provide the information flow across worksteps.
Only the dataslots specified for a workstep appear in the user interface associated with the workstep. You can use the same dataslot as the input (read-only) or output (editable) of several worksteps. Unique cases include:
*A dataslot defined as both input and output of the same workstep. In this case, the value of the dataslot is usually modified in the workstep by the Business Process Portal user.
*A dataslot defined as the output of one workstep and the input of the successor workstep. The value of the dataslot is therefore passed from the first workstep to the successor workstep.
Note that the summation of sizes of all instance dataslots must not exceed the record size. For more details about the record size specific to your database, refer to OEBPS_HOME\conf\resources\common\DatabaseMapping.xml file.

Configuring length in document and URL dataslot types

The default value for the length of a document’s name in a document dataslot or a URL address in a URL dataslot is 256 characters. If the document’s name or URL exceeds the default value, then it may be truncated or not displayed correctly. To ensure that lengthy document names or URL addresses are configured correctly, navigate to OEBPS_HOME\conf\resources\common\DatabaseMapping.xml and, under the database you are using (for example, <data-source name="openedge">), modify the default value of the mapping parameter for Document or URL dataslot to a value that encompasses the expected size of a URL.
If you have changed the size of a dataslot or the record size in the database you are using, then you must use DatabaseMapping.xml to make the corresponding changes in Business Process Server. Business Process Server and your database must be synchronized in this aspect to work correctly.

Defining dataslots in a double byte schema

Business Process Server supports double byte schema. In a double byte schema, most CHARACTER type columns are implemented as NCHAR or NVARCHAR, and such types occupies twice the space of the specified space. For example, NCHAR(10) is 20 bytes in length.
When developing applications in a double byte environment, you should carefully calculate the string length. Business Process Server cannot install applications when the number of bytes for an application table exceeds 8,039. The default size for CHARACTER dataslots is 255. On a double byte schema, the default size is 510. When possible, specify a smaller size in the Size field of the Storage tab in the New Dataslot dialog box.
Important: If the multi byte schema is set to True in the DatabaseMapping.xml file, then the byte limitation decreases to half—4030 bytes. If set to False, then the limitation remains at 8,039 bytes.