Database Reference
In-Depth Information
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Client
: The most recent versions of the Lotus client for end users have been created around
Eclipse. To interact with a Domino database, you can access APIs provided in C, C++, or
Java. Notes databases are not relational, but you can use a SQL driver with them, and the
Domino XML Language provides XML views of all data so you can use these processing
tools.
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CAP
: Lotus can be clustered and performs replication.
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Production use
: Lotus is used as an end-user collaboration tool throughout many enter-
prises.
Apache CouchDB
As a database, CouchDB is perhaps most similar to Lotus Notes. This is not entirely surprising,
as its creator, Damien Katz, worked on Lotus Notes at IBM before deciding to embark on
this project, with the idea that it would be a database ”ofthe Web.” The documents stored by
CouchDB do not need to share the same schema, and query capabilities are made available via
views, which are constructed as JavaScript functions.
CouchDB is interesting in part for what it terms Multi-Version Concurrency Control (MVCC).
MVCC means that readers will not block writers and writers will not block readers. In order to
support this, all writes occur as appends to the document store, making it much harder to corrupt
datafiles. This implementation is somewhat similar to Cassandra; using an append-only model
means that files can grow very large very quickly, requiring a background process to run com-
pactions.
NOTE
If you'd like to read more about CouchDB, check out the O'Reilly book CouchDB:TheDeinitiveGuide,
by J. Chris Anderson, Jan Lehnardt, and Noah Slater.
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Website
:
http://couchdb.apache.org
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Orientation
: Document
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Created
: Work was begun in 2005. In 2008, it became an Apache Incubator project.
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Implementation language
: Erlang
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Distributed
: Yes. Data can be read and updated by users and the server while disconnected,
and any changes can then be replicated bidirectionally later.
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Schema
: There is no required schema. Documents are stored in their entirety using JSON.
Each document is assigned a unique ID.
