Client datasets can enforce constraints on the edits a user makes to data. These constraints are applied when the user tries to post changes to the change log. You can always supply custom constraints. These let you provide your own, application-defined limits on what values users post to a client dataset.
In addition, when client datasets represent server data that is accessed using the BDE, they also enforce data constraints imported from the database server. If the client dataset works with an external provider component, the provider can control whether those constraints are sent to the client dataset, and the client dataset can control whether it uses them. For details on how the provider controls whether constraints are included in data packets, see Handling server constraints. For details on how and why client dataset can turn off enforcement of server constraints, see Handling constraints from the server.
You can use the properties of the client dataset's field components to impose your own constraints on what data users can enter. Each field component has two properties that you can use to specify constraints:
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