This command instructs pgloader to load data from a text file containing columns arranged in a fixed size manner.
Using advanced options and a load command file
The command then would be:
$ pgloader fixed.load
And the contents of the
fixed.load file could be inspired from the following:
LOAD FIXED FROM inline ( a from 0 for 10, b from 10 for 8, c from 18 for 8, d from 26 for 17 [null if blanks, trim right whitespace] ) INTO postgresql:///pgloader TARGET TABLE fixed ( a, b, c time using (time-with-no-separator c), d ) WITH truncate SET work_mem to '14MB', standard_conforming_strings to 'on' BEFORE LOAD DO $$ drop table if exists fixed; $$, $$ create table fixed ( a integer, b date, c time, d text ); $$; 01234567892008052011431250firstline 01234562008052115182300left blank-padded 12345678902008052208231560another line 2345609872014092914371500 2345678902014092914371520
Note that the example comes from the test suite of pgloader, where we use
the advanced feature
FROM inline that allows embedding the source data
within the command file. In most cases a more classic FROM clause loading
the data from a separate file would be used.
Please refer to Command Clauses for documentation about common clauses.
Fixed File Format Source Specification: FROM
Filename where to load the data from. Accepts an ENCODING option. Use the –list-encodings option to know which encoding names are supported.
The filename may be enclosed by single quotes, and could be one of the following special values:
The data is found after the end of the parsed commands. Any number of empty lines between the end of the commands and the beginning of the data is accepted.
Reads the data from the standard input stream.
The whole matching clause must follow the following rule:[ ALL FILENAMES | [ FIRST ] FILENAME ] MATCHING regexp [ IN DIRECTORY '...' ]
The matching clause applies given regular expression (see above for exact syntax, several options can be used here) to filenames. It’s then possible to load data from only the first match of all of them.
The optional IN DIRECTORY clause allows specifying which directory to walk for finding the data files, and can be either relative to where the command file is read from, or absolute. The given directory must exists.
The FROM option also supports an optional comma separated list of field names describing what is expected in the FIXED data file.
Each field name is composed of the field name followed with specific reader options for that field. Supported per-field reader options are the following, where only start and length are required.
Position in the line where to start reading that field’s value. Can be entered with decimal digits or 0x then hexadecimal digits.
How many bytes to read from the start position to read that field’s value. Same format as start.
Those optional parameters must be enclosed in square brackets and comma-separated:
See the description of field terminated by below.
The processing of this option is not currently implemented.
When the field is expected of the date type, then this option allows to specify the date format used in the file.
Date format string are template strings modeled against the PostgreSQL to_char template strings support, limited to the following patterns:
YYYY, YYY, YY for the year part
MM for the numeric month part
DD for the numeric day part
HH, HH12, HH24 for the hour part
am, AM, a.m., A.M.
pm, PM, p.m., P.M.
MI for the minutes part
SS for the seconds part
MS for the milliseconds part (4 digits)
US for the microseconds part (6 digits)
unparsed punctuation signs: - . * # @ T / and space
Here’s an example of a date format specification:column-name [date format 'YYYY-MM-DD HH24-MI-SS.US']
This option takes an argument which is either the keyword blanks or a double-quoted string.
When blanks is used and the field value that is read contains only space characters, then it’s automatically converted to an SQL NULL value.
When a double-quoted string is used and that string is read as the field value, then the field value is automatically converted to an SQL NULL value.
trim both whitespace, trim left whitespace, trim right whitespace
This option allows to trim whitespaces in the read data, either from both sides of the data, or only the whitespace characters found on the left of the streaing, or only those on the right of the string.
Fixed File Format Loading Options: WITH
When loading from a FIXED file, the following options are supported:
When this option is listed, pgloader issues a TRUNCATE command against the PostgreSQL target table before reading the data file.
When this option is listed, pgloader issues an ALTER TABLE … DISABLE TRIGGER ALL command against the PostgreSQL target table before copying the data, then the command ALTER TABLE … ENABLE TRIGGER ALL once the COPY is done.
This option allows loading data into a pre-existing table ignoring the foreign key constraints and user defined triggers and may result in invalid foreign key constraints once the data is loaded. Use with care.
Takes a numeric value as argument. Instruct pgloader to skip that many lines at the beginning of the input file.