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【转】When to use registered tables versus object-types with no super type

 
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The Problem

Developer wants to extend the Documentum object model by creating registered tables or object types that have no supertype. These extensions are generally used for storing validation, lookup, and other data.

 

Solution

Using a Documentum object type with no supertype has several advantanges over using registered tables. However, there are some situations when registered tables should be used.

 

Prior to Documentum 4.x, you could not join two object types in DQL queries. Therefore, the you were forced to use registered tables instead of object types. However, since Documentum 5.x, you can specify joins between two object types in Documentum DQL, so there is less need to use registered tables. The guidelines below indicate the factors you should consider when choosing between Documentum objects and registered tables.

 

Reasons to use Documentum object-types

  1. Documentum Object types are easier to deploy. You can use a Documentum DocApp or Composer bundle to package object-types as part of installation package. However, registered tables cannot be packaged as objects in Composer or DocApp. You can of course use pre or post installation scripts to achieve similar functionality.
  2. Business Rules can be implemented on Documentum object types using the BOF framework, but these rules cannot be implemented on registered tables.
  3. Data Dictionary can be used for Documentum object types but not for registered tables.
  4. Documentum object types allow repeating attributes.
  5. Full text Indexing of metadata is available for Documentum object types

Reasons to use Registered Tables

 

  1. The tables already exist because of integration with other database systems.
  2. The table data need to be used by other database systems.

About DFE

This article is provided by the Designed for EMC team.

 

You can discuss this article on the EDN Forums by clicking here.

 

[转自http://developer.emc.com/developer/devcenters/ContentManagement/dfe/registered_tables.htm]

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