Couchbase index: called view -- virtually another document build via map-reduce function
Map function:
Call emit() to generate a key-value pair
Reduce function:
Optional (disabled by reduce=false)
Used to calculate count, sum etc
Query View:
Call ViewResult.success() to check whether view execution is successful. Call ViewResult.error() to see error details
Set ViewQuery.debug(true) generate statistics information. Retrieved by ViewResult.debug()
Remember to call ViewQuery.development(true) if a development View has not been published as production view
For dev mode, full design doc name is: _design/dev_[designdoc name], to query it, just use designdoc name
If you specify designdoc name as dev_xxx, you get error:
com.couchbase.client.java.error.ViewDoesNotExistException: View does not exist
If you specify designdoc name as /dev_xxx or _design/dev_xxx, you get error:
{"error":"bad_request","reason":"p_w_uploads not supported in Couchbase"}
To query composite key, do not use ViewQuery.key(String), which causes additional quote to be added to the key, add get a json format error:
invalid UTF-8 JSON {error,garbage_after_value}
Uses ViewQuery.key(JsonArray) and JsonArray.from(Object[] array). Each element of array must of correct type (String or Long)
To view complete query as url parameter after encoding: use ViewQuery.toString()
Suppose a view composes of 3 field [a, b, c], it is possible to find documents by [a, b] only and [a, c] only using that view. ViewQuery.startKey([a, b, null]) and ViewQuery.startKey([a, null, c])
Sort query result: ViewQuery.desc()
References:
http://docs.couchbase.com/admin/admin/Views/views-writing.html
http://docs.couchbase.com/admin/admin/Views/views-querySample.html
Bulk operations:
Couchbase java sdk supports bulk operation, which improves performance for read/write for a number of documents
References:
http://docs.couchbase.com/developer/java-2.1/documents-bulk.html
另外有需要云服务器可以了解下创新互联cdcxhl.cn，海内外云服务器15元起步，三天无理由+7*72小时售后在线，公司持有idc许可证，提供“云服务器、裸金属服务器、高防服务器、香港服务器、美国服务器、虚拟主机、免备案服务器”等云主机租用服务以及企业上云的综合解决方案，具有“安全稳定、简单易用、服务可用性高、性价比高”等特点与优势，专为企业上云打造定制，能够满足用户丰富、多元化的应用场景需求。