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.NET Data Access Strategies for Couchbase and Language Integrated QueryUsing Couchbase with .NET
Martin Esmann Developer Advocate
twitter: [email protected]
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Who’s to blame?
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Goal!
Learn how to access data in Couchbase Server with the .NET SDK
With the main focus on N1QL
I’m assuming you know a bit about N1QL already
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Agenda
• Couchbase – Quick Overview
• Couchbase .NET SDK 2.X
• Basic Data Access Operations
• Views (…)
• N1QL – SQL like query for Couchbase
• Linq2Couchbase
• Best practices – Application Architecture and Abstractions
• What’s coming next (async, await, observable, reactive)
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Disclaimer
Details presented in this presentation may change based on customer feedback and other factors by the time the final version of the product is released.
Couchbase – Quick Overview
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Couchbase – Quick Overview
A document store and key-value store
Lightning fast: built-in caching
Query with map-reduce and N1QL
Scales massively
Key benefit: it’s simple and fast.
Challenges (before N1QL):
Data query requires more work
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Views vs N1QL
Views are sill very relevant an in many cases the recommended approach to data query.
Compared to Views, N1QL is even more flexible in terms of search capability, but with this flexibility there is a potential tradeoff for performance (automatic indexes).
In short, Views definitely have there place and so does N1QL it just depends on you specific needs.
Current demo setup
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Developer Environment Setup - Overview
Application ServerCouchbase Cluster
(3 nodes, 8GB, 4 cores)
Demo PC with Visual Studio(Code runs from here)
Windows Azure Cloud
Virtual Network(private)
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Demo Setup - Overview
Couchbase Node(1 node, 8GB, 4 cores)
Demo PC with Visual Studio(Code runs from here)
Windows Azure Cloud
N1QL DP 4(Separate download)
Virtual Network(private)
Couchbase .NET SDK
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.NET SDK overview
Main purpose of any SDK is to make life easier for developers!
• Cluster
• Bucket
• ClientConfiguration
• ClusterHelper*
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Cluster Object
• Maintains references to all open buckets
• Should be a singleton (in most applications)
• Maintains the current state of the Couchbase Cluster or Server
• Publishes config updates
• Factory for: ClusterManager
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Bucket class
• “Super API” for all other APIs
• Memcached (K/V)
• Views
• N1QL
• Subscriber for config changes
• Serialization/Deserialization
• Transcoding
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ClientConfiguration Class
• Configures bootstrapping, connection pooling and general client behavior
• Maps (“adapts”) to config file
• Allows for programmatic configuration of client
• Contains useful defaults - e.g. http:localhost:8091
• Bucket level overrides Cluster level configuration
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ClusterHelper
• Makes it “easy” to use the Cluster/Bucket
• Cluster is a singleton
• Buckets are multitons
• It will make your life easier, use it
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The IResult Interface
• As a rule the Bucket class doesn’t “throw” exceptions
• IResult is the primary interface for return values of all APIs:
• IViewResult
• IOperationResult and IentityResult
• IQueryResult
• The interface defines
• Message
• Exception
• Success
• Other info defined in more specialized interfaces
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.NET SDK Query options
• Key/value
• Views (we will not cover views in this talk)
• N1QL (pronounced nickel)
• SQL like query language for Couchbase
• “SQL for Documents”
DemoQuerying data with the .NET SDK and N1QL
Linq2CouchbaseThe best from N1QL and LINQ
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LINQ support for N1QL
Linq2Couchbase is a LINQ provider that wraps a subset of the available N1QL queries to LINQ
• An extension of the Couchbase .NET SDK 2.0
• Open Source Apache 2.0 License (Pull requests kindly accepted!)
• Github url: https://github.com/couchbaselabs/Linq2Couchbase
• Currently supports a minimal subset of the N1QL language (this will soon change)
• Errors are un-handled
• Results are mapped to POCOs
DemoN1QL with LINQ
Best practices – Application Architecture and Abstractions
Software design principles, maintainability and testable code strategies.
“craftsmanship”
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Design decisions
• N1QL in the UI layer?
• Queries in the UI Layer?
• Hard vs. Loose coupling to Couchbase SDK?
• Testability?
• Maintainability?
• Separation of concerns…
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The Repository Pattern
“Mediates between the domain and data mapping layers using a collection-like interface for accessing domain objects.”
- Martin Fowler
• Creates an abstraction between BL and DAL
• Makes it possible to write persistence store, agnostic apps
• Enabler for TDD
• In general, provides a common language and structure
accessing data
• If you don’t like the Repository, try DTO/DAO pattern or some
other data access pattern…or not!
DemoRepository pattern
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Couchbase .NET SDK version NEXTKnowledge about tomorrow can greatly help us plan
today!
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The Ubiquitous Repository
“Mediates between the domain and data mapping layers using a collection-like interface for accessing domain objects.”
- Martin Fowler
• Creates an abstraction between BL and DAL
• Makes it possible to write persistence store, agnostic apps
• Enabler for TDD
• In general, provides a common language and structure
accessing data
• If you don’t like the Repository, try DTO/DAO pattern or some
other data access pattern…or not!
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.NET SDK - Version Next
• async/await support
• Observable support
- Excepted ETA is April
• LINQ to N1QL support in SDK
- High priority, but no specific release date yet.
Summary
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Resources
• .NET SDK
https://github.com/couchbase/couchbase-net-client
• Linq2Couchbase
https://github.com/couchbaselabs/Linq2Couchbase
• N1QL installer
http://www.couchbase.com/nosql-databases/downloads
• Azure Setup guide
http://
blog.couchbase.com/hosting-couchbase-server-in-windows-azure-part-
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Key take-aways
• Couchbase supports advanced data query with N1QL
• LINQ support in the workings
• async/await + Observable support just around the corner!
• N1QL will be part of Couchbase Installer for GA (Sherlock).
Contributions are highly appreciated especially around
LINQ support for N1QL!
Forums
forums.couchbase.com
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Questions?
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Thanks for listening!Martin Esmann
Developer Advocate @ CouchbaseTwitter: martinesmann
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