RAD Studio |  |

Supporting Master/detail Relationships
See Also
Collapse All

You can create master/detail relationships between client datasets in your client application in the same way you set them up using any table-type dataset. For more information about setting up master/detail relationships in this way, see Creating Master/detail Relationships.

However, this approach has two major drawbacks:

- The detail table must fetch and store all of its records from the application server even though it only uses one detail set at a time. (This problem can be mitigated by using parameters. For more information, see Limiting records with parameters.)
- It is very difficult to apply updates, because client datasets apply updates at the dataset level and master/detail updates span multiple datasets. Even in a two-tiered environment, where you can use the database connection component to apply updates for multiple tables in a single transaction, applying updates in master/detail forms is tricky.

In multi-tiered applications, you can avoid these problems by using nested tables to represent the master/detail relationship. To do this when providing from datasets, set up a master/detail relationship between the datasets on the application server. Then set the DataSet property of your provider component to the master table. To use nested tables to represent master/detail relationships when providing from XML documents, use a transformation file that defines the nested detail sets.

When clients call the GetRecords method of the provider, it automatically includes the detail dataset as a DataSet field in the records of the data packet. When clients call the ApplyUpdates method of the provider, it automatically handles applying updates in the proper order.

See Also

Managing Transactions in Multi-tiered Applications

Extending the Application Servers Interface

Supporting Master/detail Relationships

Supporting State Information in Remote Data Modules

Setting Up the Remote Data Module

Using Multiple Remote Data Modules

Copyright(C) 2009 Embarcadero Technologies, Inc. All Rights Reserved.
What do you think about this topic? Send feedback!