pgdbf - Online in the Cloud

PROGRAM:

NAME

pgdbf - convert XBase / FoxPro tables to PostgreSQL

SYNOPSIS

pgdbf [-cCdDeEhqQtTuU] [-m memofile] filename [indexcolumn ...]

DESCRIPTION

PgDBF is a program for converting XBase databases - particularly FoxPro tables with memo
files - into a format that PostgreSQL can directly import. It's a compact C project with
no dependencies other than standard Unix libraries. While the project is relatively tiny
and simple, it's also heavily optimized via profiling - routine benchmark were many times
faster than with other Open Source programs. In fact, even on slower systems, conversions
are typically limited by hard drive speed.

Features
PgDBF was designed with a few core principles:

Simplicity. This code should be understandable by anyone who wants to hack it.

Robustness. Every syscall that might possibly fail is checked for success.

Speed. PgDBF was born to be the fastest conversion available anywhere.

Completeness. It has full support for FoxPro memo files.

Portability. PgDBF runs on 32- and 64-bit systems, and both little-endian (eg x86)
and big-endian (eg PowerPC) architectures.

Performance
PgDBF's speed is generally limited by how fast it can read your hard drives. A striped
RAID of quick disks can keep PgDBF pretty well fed on a single-processor system. One
problem area is with memo files, which may become very internally fragmented as memo
fields are created, deleted, and updated. For best results, consider placing the DBF and
FPT files on a RAM drive so that there's no seek penalty as there is with spinning hard
drives, or using a filesystem such as ZFS that caches aggressively.

One particularly fragmented 160MB table with memo fields used to take over three minutes
on a FreeBSD UFS2 filesystem. Moving the files to a RAM disk dropped the conversion time
to around 1.2 seconds.

A certain test table used during development comprises a 280MB DBF file and a 660MB memo
file. PgDBF converts this to a 1.3 million row PostgreSQL table in about 11 seconds, or at
a rate of almost 120,000 rows per second.

OPTIONS

-c Generate a CREATE TABLE statement to make a table with similar datatypes and column
names as the DBF file. Default.

-C Suppress the CREATE TABLE statement.

-d Generate a DROP TABLE statement before the CREATE TABLE statement. This is useful
for replacing the contents of a table that already exists in PostgreSQL. Default.

-D Suppress the DROP TABLE statement.

-e Change the DROP TABLE statement to DROP TABLE IF EXISTS so that newer versions of
PostgreSQL (8.2+) will only attempt to drop the table if it's already defined.
PostgreSQL will return an error when attempting to drop a table that does not exist
unless IF EXISTS is used. Default.

-E Do not use the IF EXISTS modifier to DROP TABLE for compatibility with versions of
PostgreSQL older than 8.2.

-h Print a help message, then exit.

-m memofile
The name of the associated memo file (if necessary).

-n Create NUMERIC fields with type NUMERIC. Default.

-N Create NUMERIC fields with type TEXT. Use this if rows contain invalid number data
in NUMERIC fields (which are essentially CHARACTER fields behind the scenes).

-p Show a progress bar during the conversion process.

-P Do not show a progress bar. Default.

-q Enclose the name of the table in quotation marks in statements like "CREATE TABLE",
"DROP TABLE", and so on. This is useful in cases where the table name is a
PostgreSQL reserved word, and almost certainly harmless in all other cases.

-Q Do not enclose the name of the table in quotation marks. Default.

-s encoding
Set the encoding used in the input file. When given, output will be converted from
that encoding to UTF-8. Supported encodings depend on your version of the iconv
library. Available only if your copy of PgDBF was compiled with iconv support.

-t Wrap the entire script in a transaction. Default.

-T Remove the wrapper transaction. This is generally not a good idea as it can cause
the table to appear completely empty to other clients during the data copying
phase. If the entire process occurs inside a transaction, the update is atomic and
other clients will have full access to all data in the table at all times.

-u Issue a TRUNCATE TABLE statement to clear the contents of a table before copying
data into it.

-U Suppress the TRUNCATE TABLE statement. Default.

OPTION NOTES

The -c and -d arguments are incompatible with -u as it's pointless to truncate a newly-
created table. Specifying -c or -d will disable the TRUNCATE TABLE statement as though -U
was given. Similarly, using the -u argument will disable the CREATE TABLE and DROP TABLE
statements as if -C and -D were given.

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