Information Technology Reference
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F IG . 7. Top-level SDO concepts.
It populates a data graph using state from a datastore.
It propagates a modified data graph (i.e., after an application's interactions) back
to the datastore.
The DAS ideally provides uniform data access to different datastores (e.g., relational
and XML).
Data graphs thus provide applications with a transient copy of data that has a con-
sistent API regardless of the underlying source of the data. As denoted by its name,
it presents a graph API to applications, where each node of the graph is a DataOb-
ject. The following data graph features are especially relevant to understanding how
SDOs support disconnected applications:
Changes made by an application are (optionally) automatically captured in a
“change log” history. The change log indicates which DataObjects were cre-
ated and deleted, and contains the old values of any properties that have been
modified.
Data graphs are serialized as XML, using a well-defined format, and thus ease
communication between clients and servers.
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