Apress.Expert.Oracle.Database.Architecture.9i.and.10g.Programming.Techniques.and.Solutions.Sep.2005

CHAPTER 15 ■ DATA LOADING AND UNLOADING 683
ORGANIZATION external
(
TYPE oracle_loader
DEFAULT DIRECTORY SYS_SQLLDR_XT_TMPDIR_00000
The ORGANIZATION EXTERNAL clause tells Oracle this is not a “normal” table. We saw this
clause before in Chapter 10 when we looked at IOTs. Currently there are three organization
types: HEAP for a “normal” table, INDEX for an IOT, and EXTERNAL for an external table. The rest
of the text starts to tell Oracle more about the external table. The ORACLE_LOADER type is one of
two supported types (in Oracle9i it is the only supported type). The other type is ORACLE_
DATAPUMP, the proprietary Data Pump format used by Oracle in Oracle 10g and later. We will
take a look at that type in a subsequent section on data unloading—it is a format that can be
used to both load and unload data. An external table may be used both to create a Data Pump
format file and to subsequently read it.
The very next section we encounter is the ACCESS PARAMETERS section of the external table.
Here we describe to the database how to process the input file. As you look at this, you should
notice the similarity to a SQLLDR control file; this is no accident. For the most part, SQLLDR
and external tables use very similar syntax.
ACCESS PARAMETERS
(
RECORDS DELIMITED BY NEWLINE CHARACTERSET WE8ISO8859P1
BADFILE 'SYS_SQLLDR_XT_TMPDIR_00000':'demo1.bad'
LOGFILE 'demo1.log_xt'
READSIZE 1048576
SKIP 7
FIELDS TERMINATED BY "," OPTIONALLY ENCLOSED BY '"' LDRTRIM
REJECT ROWS WITH ALL NULL FIELDS
(
"DEPTNO" CHAR(255)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"',
"DNAME" CHAR(255)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"',
"LOC" CHAR(255)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"'
)
)
These access parameters show how to set up an external table so that it processes files
pretty much identically to the way SQLLDR would:
• RECORDS: Records are terminated by newlines by default, as they are for SQLLDR.
• BADFILE: There is a bad file (a file where records that fail processing are recorded to) set
up in the directory we just created.
• LOGFILE: There is a log file that is equivalent to SQLLDR’s log file set up in the current
working directory.