DQL is short for Document Query Language and uses syntax that is a superset of ANSI-standard SQL (Structured Query Language). For those familiar with SQL, DQL can be simply thought of as a Documentum wrapper over SQL.
DQL is used to perform the following operations in a Docbase:
- Query, update, and delete objects in Docbase
- Create new objects in Docbase
- Search content in Docbase
- Query Registered tables
Example of a simple DQL query:
select r_object_id from dm_document where object_name = 'SampleDocument.xml'
The above query selects the unique Object ID of an object of type dm_document whose name is SampleDocument.xml
DQL queries can be fired from within:
- Documentum Administrator (a Documentum web client)
- DFC (Documentum Foundation Classes)
- IDQL utility
IDQL is an interactive utility/tool installed along with the Content Server and allows us to execute DQL queries against a Docbase. Figure 2.8 shows how a sample DQL query is fired using the IDQL utility.
Tip
Documentum 5.3 Update
Documentum release 5.3 has introduced a new querying approach called an FTDQL query which is similar to a SELECT statement, with the difference that the query is run against the full-text index rather than the Docbase (repository) for performance gains.
In order to learn more about DQL queries, please go through Chapter 26.