- https://docs.oracle.com/en/database/oracle/oracle-database/21/sutil/oracle-external-tables-concepts.html
- với external table, data thực sự vẫn ở file chứ không phải ở db
- Indicate the actions that can be performed using the ORACLE_DATAPUMP access driver
- Data Pump processing is done on the system selected by the specified database connect string.
- Read data from a table in the database and insert it into an external table.
- read from file and insert into db
- Job status can be displayed on request in interactive-command mode or by creating a query on DBA_DATAPUMP_JOBS.
- Character set conversions are not supported under Oracle Data Pump when using transportable tablespaces.
- The data is stored outside the database (e.g., in flat files), but the metadata (table definition, structure) is stored inside the database.
- The default reject limit is 0, which means any row that causes an error will reject the load unless the limit is explicitly changed.
- You can populate them from existing data in the database by using the CREATE TABLE AS SELECT command
- Their data can be retrieved by using only SQL or PL/SQL
- External tables are created using the SQL CREATE TABLE...ORGANIZATION EXTERNAL statement. Which of the following attributes are specified when you run the following SQL command?
- TYPE
- ACCESS PARAMETERS
- LOCATION
- DEFAULT DIRECTORY