What is dql in Oracle?

Answer 1

Introduction to DQL -Documentum Query Language-

The language used to query Documentum which is a content management

system used to create, manage, deliver, and archive all types of content from text documents and spreadsheets to digital images, HTML, and XML components.

Contents

• Define DQL

• Behind the Scenes

• Describe a SELECT statement

• Describe how search conditions are specified in a WHERE clause

• Using DQL to search a specific cabinet/folder location

• Describe the DQL REGISTER statement

DQL (Documentum Query Language) is a query language which allows you to do very complex queries involving:

1. Property searches

2. Searches for words and phrases within documents

3. Other specialized searching capabilities added for document and content management

DQL uses syntax that is a superset of ANSI-standard SQL (Structured Query Language)

• In fact, part of your DQL statements are translated automatically into SQL before being executed by the eContent Server

Behind the Scenes

• A DQL query is sent to the eContent Server using one of four API methods

readquery, execquery, query, or cachequery

• A DQL engine on eContent Server generates

- SQL queries for the RDBMS

- Verity queries for the full-text search engine

The results of the query are stored on the server in a non-persistent collection

object. Typically, a Documentum client will automatically present the results

of the query to the user in some useful way.

Alternatively, a Developer may want to use the resulting collection object or

manipulate the results programmatically.

Basic Select Statement

Select (list the properties you want returned)

From (list the type of objects you want searched)

Using WHERE clause

Allows the search to be narrowed by imposing search conditions on your

Query

select [all | distinct] value [as name] {, value [as name] } from source_list[(all)]

...

[where qualification ]

Eg :

SELECT object_name, title FROM dm_document WHERE FOLDER (ID('0b9af3ce800001ff')) AND title LIKE '%SOP%'

Searching folders and cabinets

The scope of the search can be specified as folder and cabinet in the where clause to provide a way to search the cabinet/folder hierarchy.

Eg : select object_name from dm_document where folder('/Sales')

REGISTER statement

• Registers an RDBMS table so the eContent Server can "see" it

• Allows access to data in an existing RDBMS table that may be

- created to support additional application data

- part of another application

- owned by someone else

• Does not verify that the table or its columns exist

• All columns in a table need not be registered

• Creates a dm_registered object in the System cabinet which

provides a description of the table and user access to it

REGISTER permissions

• Only the Docbase owner with a SUPERUSER privilege can register a table from

within Documentum.

• To register a table, you must have at least READ permission on the table (through the

RDBMS grant command).

• The eContent Server account (installation owner) needs the appropriate RDBMS

privileges on the table to perform different operations on rows in the table.