The COMMENT command allows you to add clarifying (semantic) explanations about tables and table columns to the data dictionary. Figure 7-20 shows the syntax diagram for this command.
Listing 7-19. Adding Comments to Columns and Tables
SQL> comment on table salgrades
2 is 'Salary grades and net bonuses';
Comment created.
SQL> comment on column employees.comm
2 is 'For sales reps only';
Comment created.
SQL> select comments
2 from user_tab_comments
3 where table_name = 'SALGRADES';
COMMENTS
-------------------------------------------
Salary grades and net bonuses
SQL> select comments
2 from user_col_comments
3 where table_name = 'EMPLOYEES'
4 and column_name = 'COMM';
COMMENTS
-------------------------------------------
For sales reps only