4 ms·

So it's not in first normal form. http://en.wikipedia.org/wiki/First_normal_form http://en.wikipedia.org/wiki/First_normal_form What's old is new again, and I w

So it's not in first normal form. http://en.wikipedia.org/wiki/First_normal_form http://en.wikipedia.org/wiki/First_normal_form What's old is new again, and I wonder if they even know it. What's not addressed is that this may not be an advance over Relational databases. In fact, when relational databases were first designed, databases like this were all-to-common, and RDBMS rejected this kind of data model explicitly, for good design reasons. For instance, how do you select from or join to parts of the complex values inside a column?

seiji 17y ago
I believe the answer is http://browsertoolkit.com/fault-tolerance.png http://browsertoolkit.com/fault-tolerance.png People are just trying to store data in the most efficient system possible. Using RDBMS software to store data only queried by primary key that you know will never need to be aggregated or dynamically queried can be overkill.
bhousel 17y ago
You have some catching up to do... :) They are not at all concerned about normal form or joins - it's just not that kind of a database. Here are some good blog posts that elaborate on the current non-RDBMS fad: http://www.readwriteweb.com/enterprise/2009/02/is-the-relational-database-doomed.php http://www.readwriteweb.com/enterprise/2009/02/is-the-relati... http://www.metabrew.com/article/anti-rdbms-a-list-of-distributed-key-value-stores/ http://www.metabrew.com/article/anti-rdbms-a-list-of-distrib... http://randomfoo.net/2009/04/20/some-notes-on-distributed-key-stores http://randomfoo.net/2009/04/20/some-notes-on-distributed-ke... http://bcbio.wordpress.com/2009/05/10/evaluating-key-value-and-document-stores-for-short-read-data/ http://bcbio.wordpress.com/2009/05/10/evaluating-key-value-a... http://blog.boxedice.com/2009/07/25/choosing-a-non-relational-database-why-we-migrated-from-mysql-to-mongodb/ http://blog.boxedice.com/2009/07/25/choosing-a-non-relationa...
th0ma5 17y ago
The guy that invented the normal forms also went on to invent analytical forms, which are the exact opposite. For example, the Entity Attribute Value (EAV) model, used by many including the W3C Semantic Web.
- blasdel 17y ago
  It's too bad that RDF has been tainted by the W3C's pipe -dreams and been bludgeoned with a terrible XML serialization. EAV is by far my favorite data model.
jbellis 17y ago
> What's not addressed is that this may not be an advance over Relational databases It's not. The relational model is much better, for many applications. BUT. The missing context is, the relational model cannot be sanely scaled out across multiple machines. Replication mostly works with some pain, but scaling writes is just a nightmare -- and what you have to do to partition your data across multiple rdbms nodes means giving up all that relational goodness. So what you end up with is neither of {easily scaled, relational}. So if you can't have a scalable rdbms, the next best thing is a scalable key/columnfamily dbms. Something like Cassandra. Which, as a bonus, gives you significantly better per-node performance on modern hardware.
- gruseom 17y ago
  Which, as a bonus, gives you significantly better per-node performance on modern hardware Could you expand on that last bit? i.e. what is it about modern hardware (and about Cassandra) that makes this true?
  - jbellis 17y ago
    Summarized here: http://news.ycombinator.com/item?id=813894 http://news.ycombinator.com/item?id=813894
- Maro 17y ago
  Can you explain what the major advantage (and disadvantage) of the data model of Cassandra over a flat key-value store is?
  - jbellis 17y ago
    You can update at the column granularity, so having a row of 100k columns is fine since you don't have to rewrite the whole thing to update a small part. (Cassandra rows have a sparse list of columns, so you can treat a row as a sorted set, not just a fixed-size vector. The model Digg describes in another article uses this: http://blog.digg.com/?p=966 http://blog.digg.com/?p=966) Columns are also indexed so you can retrieve from large rows efficiently too. Finally Cassandra also adds the concept of a SuperColumn, which is a column that contains other columns.

seiji 17y ago

I believe the answer is http://browsertoolkit.com/fault-tolerance.png http://browsertoolkit.com/fault-tolerance.png People are just trying to store data in the most efficient system possible. Using RDBMS software to store data only queried by primary key that you know will never need to be aggregated or dynamically queried can be overkill.

bhousel 17y ago

You have some catching up to do... :) They are not at all concerned about normal form or joins - it's just not that kind of a database. Here are some good blog posts that elaborate on the current non-RDBMS fad: http://www.readwriteweb.com/enterprise/2009/02/is-the-relational-database-doomed.php http://www.readwriteweb.com/enterprise/2009/02/is-the-relati... http://www.metabrew.com/article/anti-rdbms-a-list-of-distributed-key-value-stores/ http://www.metabrew.com/article/anti-rdbms-a-list-of-distrib... http://randomfoo.net/2009/04/20/some-notes-on-distributed-key-stores http://randomfoo.net/2009/04/20/some-notes-on-distributed-ke... http://bcbio.wordpress.com/2009/05/10/evaluating-key-value-and-document-stores-for-short-read-data/ http://bcbio.wordpress.com/2009/05/10/evaluating-key-value-a... http://blog.boxedice.com/2009/07/25/choosing-a-non-relational-database-why-we-migrated-from-mysql-to-mongodb/ http://blog.boxedice.com/2009/07/25/choosing-a-non-relationa...

th0ma5 17y ago

The guy that invented the normal forms also went on to invent analytical forms, which are the exact opposite. For example, the Entity Attribute Value (EAV) model, used by many including the W3C Semantic Web.

blasdel 17y ago
It's too bad that RDF has been tainted by the W3C's pipe -dreams and been bludgeoned with a terrible XML serialization. EAV is by far my favorite data model.

jbellis 17y ago

> What's not addressed is that this may not be an advance over Relational databases It's not. The relational model is much better, for many applications. BUT. The missing context is, the relational model cannot be sanely scaled out across multiple machines. Replication mostly works with some pain, but scaling writes is just a nightmare -- and what you have to do to partition your data across multiple rdbms nodes means giving up all that relational goodness. So what you end up with is neither of {easily scaled, relational}. So if you can't have a scalable rdbms, the next best thing is a scalable key/columnfamily dbms. Something like Cassandra. Which, as a bonus, gives you significantly better per-node performance on modern hardware.

gruseom 17y ago
Which, as a bonus, gives you significantly better per-node performance on modern hardware Could you expand on that last bit? i.e. what is it about modern hardware (and about Cassandra) that makes this true?
- jbellis 17y ago
  Summarized here: http://news.ycombinator.com/item?id=813894 http://news.ycombinator.com/item?id=813894
Maro 17y ago
Can you explain what the major advantage (and disadvantage) of the data model of Cassandra over a flat key-value store is?
- jbellis 17y ago
  You can update at the column granularity, so having a row of 100k columns is fine since you don't have to rewrite the whole thing to update a small part. (Cassandra rows have a sparse list of columns, so you can treat a row as a sorted set, not just a fixed-size vector. The model Digg describes in another article uses this: http://blog.digg.com/?p=966 http://blog.digg.com/?p=966) Columns are also indexed so you can retrieve from large rows efficiently too. Finally Cassandra also adds the concept of a SuperColumn, which is a column that contains other columns.