I have a custom object with a master-detail to opportunity. Is there a way to determine if the user has read or read/write access when querying this custom object?
To clarify my needs, I'm looking for a way to render my page (non-visualforce) with a clear distinction between records they have only read access to and records in which they may edit.
The user will have the same access to that as they have to the opportunity. The Profile object exposes permissions but it doesn't appear to allow you to find out about CRUD settings for objects.
Are you creating an integration piece or working with Visualforce? If you're using Visualforce the interface will respect security controls automatically, hiding data they're not allowed to see and making fields read only when using <apex:inputField> if they do not have permission to write to the field.
** Edit ** Maybe somebody will have a better solution, but how about trying to update the records you query, storing whether each was a success or failure, and then using that to control the interface? Bit of a hack, if I find anything else I'll be sure to update.
** Edit 25/01/2012 ** Have just come across this: http://www.salesforce.com/us/developer/docs/api/index_Left.htm#StartTopic=Content/sforce_api_objects_userrecordaccess.htm?SearchType=Stem
Pretty sure that'll give you exactly what you need!