Families of Views
Most of the data dictionary is constructed in a matrix fashion. The first way to categorize data dictionary views is by the breadth of information they cover. Views can be divided into four groups:
- USER_ views
Views that allow you to see objects you own. Most of these views begin with USER_.
- ALL_ views
Views that allow you to see objects that you own or that were granted to you. Most of these views begin with ALL_.
- DBA_ views
Views that allow you to see all objects in the database. These are primarily for use by the DBA. Most of these views begin with DBA_.
- Other views
A handful of other views that provide information of general interest about the database.
The second way to categorize data dictionary views is by content. Many of the USER_, ALL_, and DBA_ views are grouped in families, according to how their view names end (e.g., TABLES, COLUMNS, and so on). Groups of views provide information about various topics, including:
| Tables |
| Storage |
| Columns |
| Views |
| Objects |
| Networking objects |
The ALL_ views have the same structure as the DBA_ views. The USER_ views have the same structure as the DBA_ views with the exception that they do not include the OWNER column. In this chapter we’ll list the “family” views and the other views of interest. We’ll reference those views that exist in multiple forms (i.e., ALL_, DBA_, USER_) in the form *_viewname. So, for example, there are three *_INDEXES views:
| ALL_INDEXES |
| DBA_INDEXES |
| USER_INDEXES |
If any of the following views do not support all three varieties, ...