Sql Loader Vs External table? Which one is preffered?

Question

Hello guru,
We trying to load the data into about 160 tables. Here are the following things we are doing currently,
1. We get the flat file in .txt format
2. We are writing the control file for each flat file for thier respective tables
3.And we are using sql loader command to load this data into the table.
I was wondering if this process is cumbersome, and i m not sure if external table could be simple in loading the tables compared to what we are doing ?And i have not used external tables, so wanted to know which on eis better ? So any idea is greatly appriciated !
FYI.. Version :- Oracle 11g
Thank you so much!

Answer 1

Thanks for you reply justin !
I found the below example for loading the data into external table...
CREATE OR REPLACE DIRECTORY dat_dir AS 'C:\Oradata\Data';
CREATE OR REPLACE DIRECTORY log_dir AS 'C:\Oradata\Log';
CREATE OR REPLACE DIRECTORY bad_dir AS 'C:\Oradata\Bad';
GRANT READ ON DIRECTORY dat_dir TO scott;
GRANT WRITE ON DIRECTORY log_dir TO scott;
GRANT WRITE ON DIRECTORY bad_dir TO scott;
CREATE TABLE revext (person      VARCHAR2(20),
                     rev_jan     NUMBER(4),
                     rev_feb     NUMBER(4),
                     rev_mar     NUMBER(4),
                     rev_apr     NUMBER(4),
                     rev_mai     NUMBER(4),
                     rev_jun     NUMBER(4),
                     rev_jul     NUMBER(4),
                     rev_aug     NUMBER(4),
                     rev_sep     NUMBER(4),
                     rev_oct     NUMBER(4),
                     rev_nov     NUMBER(4),
                     rev_dez     NUMBER(4))
ORGANIZATION EXTERNAL
   TYPE ORACLE_LOADER
   DEFAULT DIRECTORY dat_dir
   ACCESS PARAMETERS
     records delimited by newline
     badfile bad_dir:'revext%a_%p.bad'
     logfile log_dir:'revext%a_%p.log'
     fields terminated by ','
     missing field values are null
     ( person,
       rev_jan,
       rev_feb,
       rev_mar,
       rev_apr,
       rev_mai,
       rev_jun,
       rev_jul,
       rev_aug,
       rev_sep,
       rev_oct,
       rev_nov,
       rev_dez
   LOCATION ('revext.dat')
PARALLEL 4
REJECT LIMIT UNLIMITED;
CREATE TABLE revenue (
    person       VARCHAR2(20),
    month        VARCHAR2(3),
    revenue      NUMBER,
    CONSTRAINT revenue_pk PRIMARY KEY (person,month));
INSERT INTO revenue (person,month,revenue)
   SELECT person,'Jan',rev_jan
   FROM revext--but currently we are using sql loader, our data looks like this
  1119Smith      01/01/1982AXYZ corporation  xyz corp
  1111collen      01/01/1990AABC corporation  abc corp
     and control file is like this
INTO TABLE "XYZ_tbl"
   ID                     POSITION(01:05)        CHAR                  "DECODE(RTRIM(:ID), NULL, 'NA', :ID)"       ,
   Name                POSITION(06:15)        CHAR                  "DECODE(RTRIM(:NAME), NULL, 'NA', :Name)"   ,
   Act_dt              POSITION(16:25)        DATE                  "MM/DD/YYYY" NULLIF ACT_DT=BLANKS
My question is, can i use the options like NULLIF/ DECODE or changing datatypes when loading or functions like REPLACE / TO_DATE in External tables ? Any idea? Any example code or SQL will great
Thank you so much!