Which statement is true regarding external tables?
A.
The default REJECT LIMIT for external tables is UNLIMITED.
B.
The data and metadata for an external table are stored outside the database.
C.
ORACLE_LOADER and ORACLE_DATAPUMP have exactly the same functionality when used with an external table.
D.
The CREATE TABLE AS SELECT statement can be used to unload data into regular table in the database from an external table.
A is true
d is true….
A or D. Which one is true. ?
d is true
Please let me know which one is correct
The default REJECT LIMIT for external tables is set to 0.
The ans is D.
Select is ok on external tables
The REJECT LIMIT clause specifies that there is no limit on the number of errors that can occur during a query of the external data. For parallel access, this limit applies to each parallel execution server independently. For example, if REJECT LIMIT is specified, each parallel query process is allowed 10 rejections. Hence, the only precisely enforced values for REJECT LIMIT on parallel query are 0 and UNLIMITED.
The metadata of external tables is created using the SQL CREATE TABLE …
ORGANIZATION EXTERNAL statement.
The actual data resides outside the database in OS files,
hence the clause ORGANIZATION EXTERNAL organization.
The data is read only.
You cannot perform any DML operations (INSERT, UPDATE, or DELETE),
nor create indexes on external tables.
You can, although, create views and synonyms for external tables.
The external table can be queried and joined directly using the SQL statement SELECT.
Which one is correct a or d?
Ans : D
The Oracle Documentation says that the reject limit is 0 for external tables. I also had D for this.
d
I have tested it, with default regect limits value, I had error by select * from ; then I had changed the regect limits:
alter table reject limit unlimited;
then I could retrieve the data! I think A is incorrect.
It’s D
D is correct
This subclause indicates the maximum number of errors that can be encountered before the INSERT statement terminates and rolls back. You can also specify UNLIMITED. The default reject limit is zero, which means that upon encountering the first error, the error is logged and the statement rolls back. For parallel DML operations, the reject limit is applied to each parallel server.