Using Data Stores
A data store references, in a process or an application system, persistent data defined in a data area.
A data store provides a mechanism to update or consult data that will persist beyond the scope of the current process. It enables storage of input message flows, and their retransmission via one or several output message flows.Introduction to the data store concept
If you describe a logical application system, only logical data stores can be used.
A logical data store represents the use of data via application systems without considering how their access will be concretely implemented.If you describe an application system, only physical data stores can be used.
A physical data store represents the implementation of a logical data store.If you describe scenario of sequences or a scenario of flows, only application data stores can be used.
An application data store materializes the usage of data in the context of a software component (for instance an application). An application data store provides a mechanism to retrieve or update information stored outside of the current software component.The Scenario of flows diagrams that describe the flows exchanged in different use scenarios of the object described.Sequences scenario that describe the chronology of the flows exchanged in different usage scenarios of the described object.Last but not least, you can also distinguish data stores local to a system from external data stores that are positioned on the border of diagrams.
A local data store represents a data store used only inside the system described.An external data store represents a data store used inside and outside of the system described.Usage contexts
The table below presents the list of diagrams that use the different types of data stores.
Data store type | Diagrams |
|---|---|
Logical data store | Logical application system structure diagrams |
Physical data store | Structure diagrams - of application, - of application system, - IT service, - microservices. |
Application data stores | Scenario sequence diagrams - of application, - of application system, - IT service, - microservices, Scenario of flows diagrams - of application, - of application system, - IT service, - microservices. |
Creating a local data store
A local data store represents a data store used only inside the system described.To create, for example, a local physical data store from an application system structure diagram:
1. Open the diagram that interests you.
2. In the diagram objects toolbar, click Local physical Data Store and select the Object Type that supports the data store you describe.
For more information on proposed object types see Access Data Stores supports.3. Click in the frame of the described application system.
4. Depending on the Object type, select then the object that interests you.
5. Click OK.
The local physical data store appears in the diagram with the name of the associated object.
Creating a external data store
An external data store represents a data store used inside and outside of the system described.To create, for example, an external physical data store from an application system structure diagram:
1. Open the diagram that interests you.
2. In the diagram objects toolbar, click external physical Data Store and select the Object Type that supports the data store you describe.
For more information on proposed object types see Access Data Stores supports.3. Click at the edge of the frame of the described application system.
4. Depending on the Object type, select then the object that interests you.
5. Click OK.
The local physical data store appears in the diagram with the name of the associated object.
Describing access to a data store
To create a read access to the data store:
1. In the diagram insert toolbar, click Link.
2. Draw a link between the data store and the entity that reads the data (component or application system use).
A Read-only access to data storage is automatically created with the link from the data store to the entity.
To create a link with write access, you must draw a link between this entity and the data store to which it has write access. A Write access to data storage is then automatically created.