From the course: Oracle Database 19c: Basic SQL
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Understanding the data dictionary
From the course: Oracle Database 19c: Basic SQL
Understanding the data dictionary
- The Oracle 19c Data Dictionary is what it sounds like, a dictionary owned by the sys user that identifies all the tables and other objects in the database. In this lesson, I'll review the characteristics of the Oracle Data Dictionary and show how it can be accessed. What is kept in the Oracle Data Dictionary? It's anything related to metadata in the database. That would include all of the database structures such as tablespaces and datafiles and what objects are stored within them. It also includes all system objects, including the synonyms for them that users need to access to know what's in the database and how to get to them. Of course, all user objects are stored there too. Whenever someone creates a table or drops a column, that's recorded and updated in the Global Data Dictionary. There are two broad of data dictionary views, dynamic performance views and permanent views, both typically accessed by a public synonym. The dynamic views begin with V$, or GV$ in a rack…
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