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

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CHAPTER 15 ■ DATA LOADING AND UNLOADING
• (DEPTNO, DNAME, LOC) (5): This tells SQLLDR what columns you are loading, their order
in the input data, and their datatypes. The datatypes are for the data in the input
stream, not the datatypes in the database. In this case, they are defaulting to CHAR(255),
which is sufficient.
• BEGINDATA (6): This tells SQLLDR you have finished describing the input data and that
the very next lines, lines 7 to 10, are the actual data to be loaded into the DEPT table.
This is a control file in one of its most simple and common formats: to load delimited
data into a table. We will take a look at some complex examples in this chapter, but this is a
good one to get our feet wet with. To use this control file, which we will name demo1.ctl, all
we need to do is create an empty DEPT table:
ops$tkyte@ORA10G> create table dept
2 ( deptno number(2) constraint dept_pk primary key,
3 dname varchar2(14),
4 loc varchar2(13)
5 )
6 /
Table created.
and run the following command:
[tkyte@desktop tkyte]$ sqlldr userid=/ control=demo1.ctl
SQL*Loader: Release 10.1.0.4.0 - Production on Sat Jul 16 10:59:06 2005
Copyright (c) 1982, 2004, Oracle. All rights reserved.
Commit point reached - logical record count 4
If the table is not empty, we will receive an error message to the following effect:
SQLLDR-601: For INSERT option, table must be empty. Error on table DEPT
This is because we allowed almost everything in the control file to default, and the default
load option is INSERT (as opposed to APPEND, TRUNCATE, or REPLACE). To INSERT, SQLLDR
assumes the table is empty. If we wanted to add records to the DEPT table, we could have specified
APPEND, or to replace the data in the DEPT table, we could have used REPLACE or TRUNCATE.
REPLACE uses a conventional DELETE statement; hence, if the table to be loaded into already
contains many records, it could be quite slow to perform. TRUNCATE uses the TRUNCATE SQL
command and is typically faster, as it does not have to physically remove each row.
Every load will generate a log file. The log file from our simple load looks like this:
SQL*Loader: Release 10.1.0.4.0 - Production on Sat Jul 16 10:59:06 2005
Copyright (c) 1982, 2004, Oracle. All rights reserved.
Control File: demo1.ctl
Data File: demo1.ctl
Bad File: demo1.bad
Discard File: none specified
(Allow all discards)