(Oracle DB) - 12. SYNONYM

/* Synonym
	#	All database objects have each unique names.
		Synonym is a database object and express the specified object.
	#	<Public synonym and Private synonym>
		- All users can refer to public synonym.
		- Specific users can refer to private synonym.
		- User granted DBA can create public synonym.
		- default format of creating synonym is private.
*/

/* CREATE Private Synonym */
CREATE OR REPLACE SYNONYM syn_channel
	FOR channels;
	-- From now on, users can use 'syn_channel' to select the table 'channels'.

SELECT COUNT(*)
	FROM syn_channel;

select username from all_users;


/* CREATE Public Synonym */
CREATE OR REPLACE PUBLIC SYNONYM syn_channel_2
	FOR channels;

GRANT SELECT ON syn_channel_2 TO PUBLIC;	-- Grant the public synonym is available to be used for SELECT 

SELECT COUNT(*)
	FROM syn_channel_2;
	

/* DROP Synonym */
DROP SYNONYM syn_channel;
DROP PUBLIC SYNONYM syn_channel_2;	-- Public synonym can be dropped with PUBLIC keyword