SQL Plus

The Data Dictionary contains views of dictionary tables. Recall from previous exercises that you can display the dictionary and its entries just like any other query. To look at the dictionary itself, the command would be: SELECT * FROM dict; SELECT * -- you could also choose specific columns rather than all of them

FROM X WHERE Y

where X is the name of a dictionary table like USER_TABLES, ALL_SYNONYMS, and so on, and Y is whatever condition (row filter) you care to place on the query. Since USER_TABLES are your tables, you do not need a Y-condition on this query to answer this question.

c. Look at which views are available to you. Use SELECT * FROM all_synonyms. You should also try SELECT * FROM xxx, where xxx is a synonym like Tab, tabs, or syn. Tab, tabs, and syn are public synonyms for dictionary tables (note that there are others).

d. Look at the description (DESC) for user_tables, user_objects, user_views, user_ synonyms. Compare the DESC user_tables to all_tables. What data is available in all_tables that is not in user_tables? Are there any columns (attributes) that are in all_ tables which are not in user_tables? What is the synonym for user_tables?

e. Display the first five rows in the following tables: dict, user_tables, all_synonyms.