PGObject::Util::PseudoCSV(3pm)

Usage

This is a parser and constructor for PostgreSQL text representations of tuples and arrays.

To parse:

For a tuple, we'd typically:

   my @list = pseudocsv_parse($text_representation);

We can then arrange the hash as:

   my $hashref = pseudocsv_to_hash(\@list, \@col_list);

Which we can combine as:

   my $hashref =  pseudocsv_to_hash(
                     pseudocsv_parse($text_representation),
                     \@col_list
   );

Version

Version 2

Overview

PostgreSQL can represent tuples and arrays in a text format that is almost like CSV. Unfortunately this format has a number of gotchas which render existing CSV-parsers useless. This module provides basic parsing functions to other programs for db interface purposes. With this module you can both parse pseudocsv representations of tuples and arrays and you can create them from a list.

The API's here assume you send one (and only one) pseudo-csv record to the API at once. These may be nested, so a single tuple can contain arrays of tuples which can contain arrays of tuples ad infinitum but the parsing only goes one layer deep tuple-wise so that handling classes have an opportunity to re-parse with appropriate type information. Naturally this has performance implications, so depth in SQL structures passed should be reasonably limited.

As of 2.0, we no longer automatically call deserialization functions from the parser itself. At his point the calling classes MUST call the deserializer themselves but this is far easier since this has been moved to a separate service in PGObject 2.0. This avoids an unnecessary dependency on PGObject and ensures that the module is more geneally useful.

Export

pseudocsv_to_hash

pseudocsv_parse

to_pseudocsv

Subroutines/methods

pseudocsv_parse

This does a one-level deep parse of the pseudo-csv, with additional levels in arrays. When a tuple is encountered it is instantiated as its type but a subarray is parsed for more entities.

Only one pseudocsv record can be passed in at once, but embedded newlines are properly handled.

pcsv2hash($literal_string, @cols);

Returns a hash from a tuple literal or array literal.

hash2pcsv($hashref, @cols)

Takes an ordered list of columns and a hashref and returns a tuple literal

pseudocsv_tohash($coldata, $colnames) DEPRECATED

Takes an arrayref of column data and an arrayref of column names and returns a hash. This is mostly a helper function designed to help with tuple types.

This interface is deprecated and will go away in 2.0. Use pcsv2hash instead.

to_pseudocsv($datalist, $is_tuple)

Takes a list of data and an is_tuple argument and creates a pseudocsv.

Note: this does not check for array sanity. If you are not careful you can get arrays returned which are not valid SQL arrays. Remember that SQL arrays have every item being the same size, and all SQL arrays are are regular in size (so all 1 and 2d arrays follow the same form as mathematical matrices).

Support

You can find documentation for this module with the perldoc command.

    perldoc PGObject::Util::PseudoCSV

You can also look for information at:

•

RT: CPAN's request tracker (report bugs here)

<http://rt.cpan.org/NoAuth/Bugs.html?Dist=PGObject-Util-PseudoCSV>

•

AnnoCPAN: Annotated CPAN documentation

<http://annocpan.org/dist/PGObject-Util-PseudoCSV>

•

CPAN Ratings

<http://cpanratings.perl.org/d/PGObject-Util-PseudoCSV>

•

Search CPAN

<http://search.cpan.org/dist/PGObject-Util-PseudoCSV/>

Acknowledgements

License and copyright

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above copyright notice, this
list of conditions and the following disclaimer in the documentation and/or
other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Releases

4 releases since Debian 10 (Buster); the text changed 2 times.