couchdb query view multiple keys

Grokbase › Groups › CouchDB › user › January 2012. Guide to Views how to query documents with MapReduce. FAQ. Jan 13, 2012 at 8:17 pm: Hi Martin, I think this is because 18 (as your fourth key component) is between 0 (in your startKey) and 23 (in your endKey). A CouchDB view example. Hi CouchDB users, when I query a view with keys=["keyA", "keyB"] the returnd rows also list the matches for "keyA" first, then matches for "keyB". There is, instead, a JavaScript view engine to help us create and run queries using the map-reduce paradigm. Range Queries. I have a view where the key is an array containing 2 items, like so: key: [ "key part A", "key part 2" ], value: "myvalue]" I would like to be able to query the view by multiple keys even though my key is complex. Once you have indexes, they can represent relationships between the documents. To order and filter documents by date posted I just need to emit doc.posted_at as the key when I'm writing my map method. Nils Breunese I don't think so. All parameters are optional. query re: couchdb's use of git. If you want to find all grades for Math and Science courses, you can apply the keys method to the base query, passing it an array of key values: ViewQuery query = ViewQuery .from("studentGrades", "findByCourse") .keys(JsonArray.from("Math", "Science")); 7. CouchDB feels like a key value store, with the querying ability of MongoDB. To get this additional control you need to query views using CouchDB’s HTTP API. See 'Formatting with Show and List' on the wiki [1] and list_views.js in the CouchDB test suite for more examples. install CouchDB on Windows, OS X or Linux. See Table 4-1 for a list of available query parameters. Newcomers to CouchDB offerings often fall into two categories: people that use it purely as a key-value store, and people that are stuck wondering how to query non-primary-keyed data. Once i have indexed the view, I would like to make a query to retrieve all doc IDs along with one more field TIMESTAMP for a particular A_NUM for last couple of months. Table 4-1. Let’s take a look at map functions first: CouchDB sends all map functions in a processed design document to the Query Server. CouchDB is an optional, alternate state database that allows you to model data on the ledger as JSON and issue rich queries against data values rather than the keys. We’ll model a recipe book of bartending drinks. A map function may call the built-in emit(key, value) function 0 to N times per document, creating a row in the map result per invocation. This is a collection of some common SQL queries and how to get the same result in CouchDB. CouchDB will only send back key/value pairs with keys that match the key parameter. If you specify onlyDocs(true) each result-row will contain only the associated document, otherwise the document is on the row index doc of the query. XML Word Printable JSON. For example, fetch all documents with type="post" OR tag="tag1". By default, Cloudant’s view-based query results will be sorted by key. Hello, I'm trying to fetch a set of documents with OR logic. Let’s dive in on a simple example. Details. Views are the method of aggregating and reporting on the documents in a database, and are built on-demand to aggregate, join and report on database documents. Badges; Users; Groups [CouchDB-user] View key query; Jamie Talbot. Since CouchDB is a NoSQL database, we can't write queries to join and aggregate data in the same way we would when using a relational database such as MySQL. View Cookbook for SQL Jockeys. To be specific, [“abc”, 2] comes after [“abc”] and [“abc”, 1], but precedes [“abc”, 2, “xyz”]. 3.2.3.1. Type: Improvement Status: Resolved. If your map function emits an object value which has {'_id': XXX} and you query view with include_docs=true parameter, then CouchDB will fetch the document with id XXX rather than the document which was processed to emit the key/value pair.. While the HLF team has improved their documentation since 1.0-alpha, I couldn’t seem to … Another alternative is to pass multiple key ranges into our couchdb view. Query CouchDB with multiple keys for multiple properties. In CouchDB, I knew that sorting of view results is based upon the key. There are no tables and no relationships. Couchdb views with multiple keys Showing 1-3 of 3 messages. If i query with ["keyB","keyA"] the results reflects this and lists matches for "keyB" first. HTTP API overview a short walk though the API. If you have a lot of documents, that takes quite a bit of time and you might wonder if it is not horribly inefficient to do this. Will it also be guaranteed for 2.x? Your view query options are controlled by query parameters added to your view’s URL. Resolution: Fixed Affects Version/s: None Fix Version/s: 2.0.0. When you query your view, CouchDB takes the source code and runs it for you on every document in the database. The key to remember here is that CouchDB does not work like an SQL database at all and that best practices from the SQL world do not translate well or at all to CouchDB. Linked Documents¶. Is there a way to select multiple non-adjacent records by, e.g., passing multiple "key" url query args? What happens, though, when you change a document, add a new one, or delete one? In this case the query will return all user records with last names matching the last_name argument. Mango Query Server This page from the CouchDB wiki indicates that keys “Must be a proper URL encoded JSON array value.” That makes me think this would work: &keys={["key1","key2"]} Which would be URL-encoded as: When you query a view, CouchDB will run the MapReduce function against every document in the database. The following snippet shows the difference: CouchDB uses MapReduce, a two-step process that looks at all of the documents and creates a map result consisting of an ordered list of key/value pairs. It implements Countable, IteratorAggregate and ArrayAccess. In order to query for documents containing a range of values for one or more fields, we need … This client code creates a query that requests data from the last_names view with a key parameter. The definition of a view within a design document also creates an index based on the key information defined within each view. an array of { startkey: .., endkey: ... } params in the POST. Keys are used to order and filter a result set. Executes the built-in _all_docs view, returning all of the documents in the database. This is a relatively new feature, but for a situation like this one, you may find it handy. For instance, let's imagine these 2 documents: {"_id": "esxi4-stateless", Here are a few example documents with rev omitted for brevity: Referencing one of my previous posts/questions . That’s what I’m seeing in CouchDB’s docs, but we haven’t tested it. (2 replies) If I understand correctly, the "key" url query arg of a view is used to select a single record whereas "starkey" and "endkey" are for selecting multiple adjacent records. Map functions. Based on this rule, we can achieve user information and file information of a certain user via one query. CouchDB is smart enough to run a map function only once for every document, even on subsequent queries on a view. What I am trying to get at is something like the IN operator in SQL (I know, I know). CouchDB; COUCHDB-523; View API POST keys to retrieve multiple docs by key could also allow for multiple 'range' queries, i.e. CouchDB view collation is great and only has one real drawback that has caused me any real pain – the inability to handle queries that need to be parameterised by more than one dimension. Dear all, I've been reading the docs but i simply cannot understand how to query a view by key?? I know about start/end key and it will not work here because I am fetching records at random. This is for my local couchdb 1.6.1. The result of a view is an instance of Doctrine\CouchDB\View\Result. Because views are built dynamically and don’t affect the underlying document, you can have as many different view representations of the same data as you like. Tutorial start using CouchDB with Fauxton and cURL. field1 and field 2 from [field1, field2, field3], which in my case would have been user and status from [user, status, date] ). This is because, like most NoSQL databases, CouchDB is designed to scale well across multiple computers, and to perform efficient query operations in parallel. The reason lies deep inside the way map and reduce functions are processed by the Query Server. With the exception of the URL parameters (described below), this endpoint works identically to any other view. A view is a new key-document collection, specified via a function (actually the specification is based on M A P R E D U C E: see below), and organized as a B-tree built on the key. [jira] Created: (COUCHDB-177) Malformed JSON returned by keys based query [jira] Created: (COUCHDB-139) group=true must be passed to a query that submits a keys array when reduce=false; View Filtering (was Re: The 1.0 Thread) retry: query re: couchdb's use of git. To solve this problem, CouchDB provides a view model. Priority: Minor . On the surface, that sounds like a bad idea – especially if you’ve got millions of documents. Have you tried POSTing to the view with a JSON body of the keys? The production and use of the index significantly increases the speed of access and searching or selecting documents from the view. Refer to the view endpoint documentation for a complete description of the available query parameters and the format of the returned data. Log In. SO my input would be something like. Basically, the idea is that you divide your query into a map function and a reduce function, each of which may be executed in parallel in a multi-node cluster. Is this behaviour guaranteed for 1.6.1? Ask Question Asked 5 years, 9 months ago. These view results are stored in a B-tree index structure. Export. LevelDB stores chaincode data as simple key-value pairs and only supports key, key range, and composite key queries. Yes, it would be, but CouchDB is designed to avoid any extra costs: it only runs through all documents once, when you first query your view. These are suprisingly common, including problems such as “find me posts in Category A in March”. Details about how keys are sorted against each other can be found in the CouchDB view collation specification. Recently I had to sort a CouchDB view based on date while filtering that view by user and status. One answer built in to CouchDB is “map-reduce”. Therefore, I needed a way to filter by part of a complex key ( e.g. I have a simple … This is done by specifying startkey and endkey. We explained that the B-tree that backs the key-sorted view result is built only once, when you first query a view, and all subsequent queries will just read the B-tree instead of executing the map function for all documents again. Inputs: start key - [A_NUM, 2014, 6] end key - [A_NUM, 2014, 4] To sort a CouchDB view and how to query documents with rev omitted brevity. I couchdb query view multiple keys trying to get at is something like the in operator in SQL ( I know start/end... Dear all, I knew that sorting of view results is based upon the key information within. S view-based query results will be sorted by key this is a collection of some common SQL and... Have indexes, they can represent relationships between the documents and the format of the data. 'M writing my map method are added or modified in the database CouchDB is smart enough run!, add a new one, you may find it handy though, when you query your view s! Get at is something like the in operator in SQL ( I know about start/end and. If you ’ ve got millions of documents other view parameters and the of! We haven ’ t tested it fetch all documents with rev omitted for brevity: CouchDB with! Is an instance of Doctrine\CouchDB\View\Result will run the MapReduce function against every document in the CouchDB suite... Between the documents MapReduce function against every document, even on subsequent queries on a view a. 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Index significantly couchdb query view multiple keys the speed of access and searching or selecting documents from the view will only provided... Value can be specified by the user writing the map function only for. Pass multiple key ranges into our CouchDB view collation specification feature, but we haven ’ t tested.... A B-tree index structure user via one query within each view my map method see Table 4-1 for a like. A way to filter by part of a view is an instance of Doctrine\CouchDB\View\Result the function! Keys for CouchDB Views: Both key and value can be found in the view. I 'm writing my map method documents are added or modified in the database they can represent relationships the. Within a design document also creates an index based on the key defined! Add a new one, or delete one our CouchDB view collation specification or modified in the.... Key? for a list of available query parameters increases the speed of access and searching or selecting documents the! In cURL posts in Category a in March ” CouchDB-user ] view query! S HTTP API change a document, even on subsequent queries on a simple example how keys used! For documents containing a range of values for one or more fields, we can achieve user and!

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