If we choose SHA1 as hash, then seg_hash is a 20 byte long binary. I suggest renaming the field to seg_sha1 (or whaterver hash we choose) to make it clear what the data is. Also allows a bit more for future change of hash function with fallback to the previous hash.

Need to investigate table creation scripts, read a bit of docs and what not.

Blocked by T248472

New suggestion.

Hash is unique per page. Not for the whole site, i.e. page_id must be added.
seg_hash is SHA256, 256 bytes. 64 lower case hex characters. 44 base64 characters. Or a blob. I'd go for the hex string.

@kalle Digging a bit into how the file hash seems to be handled it looks like its converted to a different base very early on. This makes use of base_convert. See function making use of it

Change 596674 had a related patch set uploaded (by Karl Wettin (WMSE); owner: Karl Wettin (WMSE)):
[mediawiki/extensions/Wikispeech@master] Create database for utterance data

https://gerrit.wikimedia.org/r/596674

Aw man, did I just try to review to master rather than a new branch? Let me abandon that patch and do it again!

Change 596674 abandoned by Karl Wettin (WMSE):
Create database for utterance data

Reason:
Managed to create patch on Master rather in a new branch. ABORTING

https://gerrit.wikimedia.org/r/596674

Change 596676 had a related patch set uploaded (by Karl Wettin (WMSE); owner: Karl Wettin (WMSE)):
[mediawiki/extensions/Wikispeech@master] Create database for utterance data

https://gerrit.wikimedia.org/r/596676

These are functions we need to discuss. They are WiP. Perhaps I shouldn't have included them yet, but it was just too tempting.

	/**
	 * Clears database of utterances older than a given age.
	 *
	 * @since 0.1.3
	 * @param $maximumAgeHours
	 */
	public function flushUtterancesByExpirationAge ( $maximumAgeHours ) {
		// todo flush items from file storage here?
		// todo return identity of flushed utterances?
	}

	/**
	 * Clears database of all utterances for a given page.
	 *
	 * @since 0.1.3
	 * @param $page_id
	 * @param $language
	 * @param $voice
	 */
	public function flushUtterancesByPage ( $page_id, $language, $voice ) {
		// todo flush items from file storage here?
		// todo return identity of flushed utterances?
	}

	/**
	 * Clears database of all utterances for a language and voice.
	 *
	 * @since 0.1.3
	 * @param $language
	 * @param $voice
	 */
	public function flushUtterancesByLanguageAndVoice ( $language, $voice ) {
		// todo flush items from file storage here?
		// todo return identity of flushed utterances?
	}

Change 596676 merged by jenkins-bot:
[mediawiki/extensions/Wikispeech@master] Create database for utterance data

https://gerrit.wikimedia.org/r/596676