I like the idea of reusing the WideColumn class also for Cassandra. Is "Wide Column" a term that you've encountered elsewhere, or did you make that up? I kinda like it, but would want to consider naming as important.
One piece of perspective too is that some databases (notably MongoDB, CouchDB, ElasticSearch) support "wide rows" in a way, meaning that any particular row may contain additional fields outside of the norm. Maybe we could introduce both WideRow and WideColumn interfaces to support that sort of behaviour? Kasper 2018-05-22 7:25 GMT-07:00 Arjan Seijkens <a.seijk...@quadient.com>: > Hi, > > > > In the context of an internship we have been working on extending HBase > support for MetaModel, mainly focusing on adding write support. > > > > Right now there is a pull request for this on a MetaModel fork, which can > be found here: https://github.com/GerardDellemann/metamodel/pull/2. Note > that we will probably have to replace this pull request with a new one to > be able to merge it into MetaModel master instead of the fork. > > > > There is one specific change within this pull request which I would like > to discuss here. > > > > Within this pull request we introduce the HBaseColumn class, which extends > the AbstractColumn class and which represents a column in an HBase table. > We introduced this class because HBase uses a Wide column store for it's > database model, which works in a different manner as relational database > columns. > > > > In its current state the HBaseColumn class has two important new methods: > > - HBaseColumn#getColumnFamily() > - HBaseColumn#getQualifier() > > > > From this perspective each Column always has a Column family and > optionally has a qualifier. If a Column has both a Column family and a > qualifier, we are able to get a specific value from a table row based on > that column. If a Column only has a Column family, we don't know which > qualifiers it has, which can be a typical use case because qualifiers are > dynamic and can be different for each row, then when getting the value from > a table row base on that column, we get a list of all values. > > > > This is how it's implemented now in the pull request. > > > > I would like your opinion on this, so fire away. Some considerations: > > - Maybe we shouldn't call the class HBaseColumn, but rename it to > WideColumn instead and do some more renaming of the methods, so it can be > reused later on for Cassandra. > - In the current implementation the HBaseColumn supports both using it > with and without a qualifier, which causes different behaviors, is this > desirable, or should we create two different classes? > > > > Furthermore all other feedback on the pull request is welcome, but you can > also wait with that until we replace it with a pull request to actually > merge it into MetaModel (instead of into the fork). > > > > Kind regards, > > > > Arjan Seijkens > > *Technical Lead Quadient DataCleaner* > > Research & Development > > > > [image: Quadient] > > *Quadient®* > > a: > > Utrechtseweg 310, Building H31 > <https://maps.google.com/?q=Utrechtseweg+310,+Building+H31+%0D%0A+6812+AR+Arnhem+%0D%0A+%0D%0A+The+Netherlands&entry=gmail&source=g> > 6812 AR Arnhem > <https://maps.google.com/?q=Utrechtseweg+310,+Building+H31+%0D%0A+6812+AR+Arnhem+%0D%0A+%0D%0A+The+Netherlands&entry=gmail&source=g> > > The Netherlands > <https://maps.google.com/?q=Utrechtseweg+310,+Building+H31+%0D%0A+6812+AR+Arnhem+%0D%0A+%0D%0A+The+Netherlands&entry=gmail&source=g> > > w: > > www.quadient.com e: a.seijk...@quadient.com > > > > [image: > https://go.pardot.com/l/68752/2015-06-17/dymgk/68752/22130/Twitter_icon_2.png] > <https://twitter.com/Quadient> [image: > https://go.pardot.com/l/68752/2015-06-17/dymg7/68752/22126/LinkedIn_icon_2.png] > <https://www.linkedin.com/Quadient/> [image: > https://go.pardot.com/l/68752/2015-06-17/dylq7/68752/22120/Facebook_icon_2.png] > <https://www.facebook.com/Quadient> [image: > https://go.pardot.com/l/68752/2015-06-17/dymgy/68752/22132/YouTube_icon_2.png] > <https://www.youtube.com/channel/UCdOGV3K4rE7t9dW7A7JNN7w> > > > > The information contained in this e-mail is intended only for the > individual to whom it is addressed. It may contain privileged and > confidential information. If you have received this message in error or > there are any problems, please notify the sender immediately and delete the > message from your computer. The unauthorized use, disclosure, copying or > alteration of this message is forbidden. Quadient and/or its worldwide > subsidiaries will not be liable for direct, special, indirect or > consequential damage as a result of any virus being passed on, or arising > from alteration of the contents of this message by a third party. > > > > Quadient, Max Höggerstrasse 6, CH-8048 Zurich > <https://maps.google.com/?q=Max+H%C3%B6ggerstrasse+6,+CH-8048+Zurich&entry=gmail&source=g> > > >
