Posts Tagged ‘dictionary’

A more relational dictionary

As I started looking to add more functionality to Lexiio, I realized the Wiktionary definitions database dump I was using wasn’t going to cut it; specifically, I needed a normalized schema, or I’d have data duplication all over the place. I started normalizing in MySQL, but whether it was MySQL or MySQL Workbench, I kept running into character encoding issues. Using a simple INSERT-SELECT, in MySQL 5.7, to transfer words from the existing table to a new table resulted losing characters:

MySQL losing characters

I dumped the data into PostgreSQL, didn’t encounter the issue, and just kept working from there.

The normalized schema can be downloaded here: LexiioDB normalized
(released under the Creative Commons Attribution-ShareAlike License)

LexiioDB schema

The unknown_words and unknown_to_similar_words tables is specific to Lexiio and serve as a place to store unknown words entered by the user and close/similar matches to known words (via the Levenshtein distance).

Lexiio

pf34m2m522

Wiktionary definitions database

Having a dictionary can be incredibly useful in software development, and forms the basis for a wide range of natural language processing applications. However, finding an open-source dictionary, one that can be easily parsed and used within applications, is incredibly difficult as there simply isn’t a lot of options available.

WordNet is one option I came across, but requires significant work parsing the WordNet ASCII database files or Prolog database files.

Wiktionary was the other viable option, and the one I went with. The Wiktionary XML dumps are available, but being a wiki, these files are likely even more difficult to parse than the WordNet database files as you’d have to deal with wiki markup. However, a while ago I was able to get a TSV file with words, parts of speech, and definitions from the Wikimedia Toolserver at http://toolserver.org/~enwikt/definitions. The Toolserver has since been discontinued and I haven’t found updated TSVs hosted anywhere else, but the file I downloaded, dated November 27, 2012, is still fairly up-to-date for a dictionary and useful in many applications.

I wrote a PHP script to parse the TSV and make INSERTs into a MySQL database. The TSV file, MySQL database, and PHP script are presented below.

Wiktionary TSV file

Wiktionary MySQL database export

PHP Script:

<?php

require "Database.php";

$tsvInputFilePath = "TEMP-E20121127.tsv";

echo "Importing {$tsvInputFilePath} ...\n";

// Open file
$fp = fopen($tsvInputFilePath, "r");
if($fp === FALSE) {
echo "Could not find file path: " . $tsvInputFilePath;
exit;
}

// Establish DB connection
$db = new Database();

while (!feof($fp)) {

// Get line and parse tab-delimited fields
$ln = fgets($fp);
$parts = explode("\t", $ln);
if(count($parts) < 4) {
continue;
}

$lang = $parts[0];
$word = $parts[1];
$partOfSpeech = $parts[2];
$definitionRaw = $parts[3];

// Insert into database
$db->query("INSERT INTO words (language, word, part_of_speech, definition_raw)
VALUES (?, ?, ?, ?)"
,
$lang, $word, $partOfSpeech, $definitionRaw);

}

echo "done.\n";
exit;

The Database class is wrapper for mysqli, you can find it, along with the script above, in the wiktionary-tsv-import bitbucket repo.

Note that definitions need to be parsed further, as they contain wiki markup. The parsing doesn’t seem difficult and is something I hope to get done in the near future.

Related resources:

There’s valuable stuff from each of the projects above, but like WordNet, requires significantly more time to evaluate and implement in an application, compared to the simple TSV -> MySQL translation.

EDIT (12/13/2015): I’ve updated the MySQL database export. There was some holes in the data because I was using utf8 column encoding for definitions, however, MySQL’s has a weird “UTF-8” implementation that only handles codepoint that up to 3 bytes in size. utf8mb4 encoding needs to be used for a proper UTF-8 encoding supporting up to 4 bytes.