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Oracle SQL Plus The Definitive Guide- P23

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Oracle SQL Plus The Definitive Guide- P23:Every day, computer professionals the world over wake up, travel to the office, sit down in front of a computer, and begin another day working with that database called Oracle. Programmers write queries and stored procedures. Database administrators monitor performance, make database changes, and perform other maintenance tasks. Operations people may need to back up or recover a database. | previous page page_191 next page previous page page_192 next page Page 192 Table 6-9. Columns in the ALLTRIGGERCOLS View continued TABLE_OWNER The owner of the table on which the trigger is defined. Usually this is the same as the trigger owner but it doesn t have to be. TABLE_NAME The name of the table on which the trigger is defined. COLUMN_NAME The name of a column in the table that is used within the trigger either within the trigger s specification or within the PL SQL block executed by the trigger. COLUMN_LIST Either YES or NO depending on whether or not the firing of the trigger is dependent on this column being updated. This is only applicable to UPDATE triggers. A value of YES indicates that the column forms part of the column list following the keyword UPDATE in the CREATE TRIGGER statement. COLUMNUSAGE This tells you how the column is used within the trigger. It will contain some combination of the following strings separated by one space NEW The new version of the column is referenced. OLD The old version of the column is referenced. IN The column is referenced but not updated. OUT The column s value is set but never read. IN OUT The column s value is both referenced and updated. For example a value of NEW IN OUT tells you that the trigger both sets the value of the column OUT and reads the value of te column IN . It also tells you that it is the new version NEW of the column that is used. The ALL SYNONYMS view The ALL_SYNONYMS view returns one row for each synonym you own and one for each public synonym. Table 6-10 describes the columns in this view. Table 6-10. Columns in the ALL SYNONYMS View Column Contents OWNER The owner of the synonym. The owner name will be PUBLIC for public synonyms which are accessibe by all detabase users. SYNONYM_NAME The name of the synonym. TABLE_OWNER The name of the table s owner. TABLE_NAME The table name to which the synonym points. DB_LINK If the synonym points to a table in another database instance this is the .