- Generating the CDM
- Special case: Updating an existing LDM
Generating the LDM from the CDM
To associate a CDM (Conceptual Data Model) with a project, you must generate the associated LDM
(Logical Data Model). Indeed, it is the LDM that is associated with the project (and not the CDM).
Generating the CDM enables you to automatically create the corresponding LDM after checking the validity of the CDM .
To generate the LDM from the CDM:
- On the "CDM" tab, in the "Analysis" group, click "Generate logical model".
- Define the parameters for generating the LDM from the CDM:
- the name and path of the generated LDM. The LDM corresponds to a ".WDA" file. By default, this file will be created in the directory of the project analysis (<Project name>.ANA directory). This directory must be accessible in read/write mode.
- whether the captions of the associations without property (in the CDM) are kept to identify the links of the LDM ("Generation" tab).
- the type of access to the data files ("File" tab). Depending on the selected type, the data files will be handled by the WINDEV engine, by an OLEDB driver or by one of the native accesses of WINDEV, WEBDEV and WINDEV Mobile (SQL Server, Oracle, ...).
- the data files access type used.
- the format of the characters used in the analysis.
- Validate the generation. The LDM corresponding to the CDM is automatically created.
Special case: Updating an existing LDM
If the name and path of the LDM specified when generating the CDM correspond to an existing LDM, the existing LDM will be updated with the new description of the CDM.
When updating an existing LDM, the generation checks:
- The existence of the entity in the LDM:
- if the entity is new, the corresponding file is created.
- if the entity already exists, its properties are updated.
- The existence of the properties in the LDM:
- if the property is a new one, the corresponding item is created.
- if the property already exists, with the same description, no action is performed.
- if the property already exists, with a different description, a conflict occurs. The data model editor proposes:
- to ignore the new description of the property and to perform no modification.
- to update the existing item with the new description of the property.
- to create a new description synonym with the new description of the property.
- The existence of relationships and associations. When the association requires the creation of one or more relation files, the LDM files and items are updated as described above. When a relationship is modified, the link with the LDM is re-created or updated:
- if the identifying properties of one of the entities have been modified, the cardinality of the existing links are updated and new links are created.
- if no identifying property of one of the entities was modified, the cardinalities are updated.
- The deletion of entities, relationships or associations are not taken into account when generating a CDM into a LDM.
- The deletion of the entity properties can be taken into account by unchecking "Keep the LDM modifications" in the options for generating the LDM from the CDM. In this case, the files of the LDM only contain the items of the corresponding entity in the CDM after the conversion.
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