21.Oracle - The self documenting dictionary

Oracle - The self documenting dictionary

Oracle's Data dictionary is itself self documenting. we can query DICTIONARY AND DICT_COLUMNS views for descriptions of the data dictionary views and their columns.


The following query gives the descriptions of all of the data dictionary views.

SELECT table_name, comments
FROM dictionary
ORDER BY table_name;

It gives the large amout of output. By using where class we can focus a smaller set of views as like the following query.

SELECT table_name, comments
FROM dictionary
WHERE table_name LIKE '%TABLE%'
ORDER BY table_name

It returns all views containing the word 'TABLE'

Like wise We can query the DICT_COLUMNS view also. It gives the descriptions for the columns for all views. Following query retrieves descriptions for the columns in ALL_TAB_COLUMNS.


SELECT column_name, comments
FROM dict_columns
WHERE table_name = 'ALL_TAB_COLUMNS';

This is a sample one. We can learn lot about oracle through data dictionary views, they are not available at any oracle site.


Thanks..!