Unload data to a flat file from Oracle database

From : asktom

[@more@]How Can I unload data to a flat file

Many times we are asked

• "Does anyone know an easy way of dumping the data from an Oracle table into a delimited(comma, tab etc) ascii file?"
• "Does anyone know an easy way to unload data in a format for sqlldr to reload later?"

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Well here is a way to do it into Excel or any spreadsheet that understands the industry standard SYLK file format:

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Here is a pro*c program that does it to a flat file very fast:

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and here is a PLSQL routine that uses utl_file to do the same:
A reader (Andy Rivenes) offers this more "robust" plsql implementation based on the original code

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And lastly, SQLPlus can do this quite easily but it is a pain to have to write a script/table. What I've done is setup scripts for UNIX and NT that allow you from the command line to execute things like:

$ sqlldr_exp scott/tiger dept
LOAD DATA
INFILE *
INTO TABLE dept
REPLACE
FIELDS TERMINATED BY '|'
(
deptno
,dname
,loc
)
BEGINDATA
10|ACCOUNTING|NEW YORK
20|RESEARCH|DALLAS
30|SALES|RESTON
40|OPERATIONS|BOSTON

As you can see, this script unloaded the scott.dept table into a format that sqlldr can easily reload. All you would need to do is execute:

$ sqlldr_exp scott/tiger dept > dept.ctl

to create a control file that can be moved somewhere else and reloaded back into a dept table very quickly.

I also use a slight modification of this script called "flat". Flat does the same thing as sqlldr_exp does mostly except that it dumps the data into a tab delimited format without the sqlldr extras at the top. This makes the extract usable in spreadsheets and such.

In both cases some things you need to be aware of are with regards to this script:

• There is an absolute limit of 2000 bytes in 7.x and 4000 bytes in 8.x per line/row for unloaded data. The total size of the unloaded data is unlimited -- the maximum size of an individual row of data is what is limited.
• It makes no attempt to unload dates with the century or time component -- you must change your default NLS_DATE_FORMAT if this is a problem.
• Beware of data with pipes or tabs in it!
• Beware of data with newlines as well...
• The NT scripts (.cmd files) need modifications if your command line sqlplus is not called SQLPLUS (eg: its plus33 or something similar)
• On NT, you need to set your SQLPATH environment variable and put these files into that directory OR you need to run flat and sqlldr_exp from those directories so sqlplus can find the corresponding flat.sql and sqlldr_exp.sql files.

You can download the UNIX and NT scripts here. They are in a a file "unloader.zip" which can be opened with WinZip 6.0 or up on windows.

Alternately, you can get a gzipped tar file for use on Unix without zip.