With Oracle RDBMS: Everything is SQL

Everything is SQL, and SQL is Everyting.

One of the things I really like about Oracle RDBMS is that it follows the “12-rules of Codd” very well. 

And What I specifically like, All of the RDBMS information is accessible via SQL.

In Oracle, “Everything is a Table or View”. 

And thus, everything can be queried by SQL. 

If you need to observe or “diagnose” your Oracle Database, you can (and should) do so via SQL. And you will also learn a few things every time you delve into something. 

 Disclaimer: I'm writing this bcse I am trying to convince some newbies and DevOps folks to learn just a little more about Oracle.... 

 This blogpost is to show you how you can Get to Know Everything about your Oracle database by just using the SQL interface. For example: I can ask what tables are in my current schema with a query on a view called "USER_TABLES" 

SCOTT @ ORCLPDB1 > select table_name from user_tables order by 1 ;

TABLE_NAME 

-----------------------

DEPT

EMP

LOG_STATS

PT PT_C

PT_CC

PT_CCC

T

T_C

T_CC

T_CCC

11 rows selected. 

SCOTT @ ORCLPDB1 > 

And if you want to dig deeper: you can ask the database where it stores the actual datafiles, for example from v$datafile: 

SCOTT @ ORCLPDB1 > select name from v$datafile ; 

NAME 

------------------------------------------------------------- 

/opt/oracle/oradata/ORCLCDB/ORCLPDB1/system01.dbf /opt/oracle/oradata/ORCLCDB/ORCLPDB1/sysaux01.dbf /opt/oracle/oradata/ORCLCDB/ORCLPDB1/undotbs01.dbf /opt/oracle/oradata/ORCLCDB/ORCLPDB1/users01.dbf 

SCOTT @ ORCLPDB1  >

And in that spirit, following notably rule nr 4 of Codd, all the data and metadata of your Oracle database can be found via SQL. 

I strongly encourage any DBA (and Developer, Devops, etc.. ) to explore the available documentation on the DBA_% and V$... views. Everything you need to know about your database is There. And much more.  All reachable with Select-statements. 

Link to the official doc here ....

note: Compare Oracle to unix/linux. Those of you who are brought up with unix/linux will recognise this. In unix, “Everything is a File”. 

My fingers are itching to show more SQL and to show how you can inspect the darker corners of your database with some some nifty SQL-stmtns.

Also, I want to make some points about tooling, issue some tips and some Warnings. With powerfull tools comes some responsability on using them correctly. 

The more I think (write) about it, the more there is to elaborate upon.

Guess I have to do some more blogs...

But my main message would be: Check the 12 rules of Codd, and explore some of the documentation about the internal views. There is your starting point.

For now, just remember: Everything is SQL !