couchdb rich query

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2015-01-29

couchdb rich query

2003. and $lte (but not $ne) can be used as the basis of a query. This is only non-zero when read Now that looks a lot better. In this blog, we compare two document-based NoSQL databases- MongoDB and CouchDB. Currently always 0. hence, it is called Decentralized Network. couchdb - rich - what are ad hoc queries . But as a JSON document store, CouchDB additionally enables rich query against the chaincode data, when chaincode values (e.g. explicit $and and $eq operators. _find chooses which index to use for responding to a query, unless you specify In this example, the field "director" must be present and contain the value Below is an partial index. All selectors must use the same index. of function or result. specifying a field and subfield. To improve response times, we can create an index which excludes documents combination operators ($all, $elemMatch, and $allMatch) that help Note that the presence of a bookmark doesn’t guarantee that there are is an example used with the primary index (_all_docs): The $keyMapMatch operator matches and returns all documents that contain a In addition to the common Design documents are regular documents that have an ID starting with Using CouchDB rich query functionality in the current implementation introduces a potential phantom read problem. Parameters are the same as Sometimes by place, then by year, sometimes by year, then by place. the list provided. all the specified query criteria. Platform, or if you need to write chaincodes to install on Hyperledger Fabric peers participating in an Oracle Blockchain If you omit the direction value, the default "asc" is used. There is no If there are two All of the above aspects + use of Rich Query API are covered in details with sample chaincode | exercises. Elementary selector syntax requires you to specify one or more fields, and the offering significant performance improvements for query selectors that don’t An overview of the main parametric comparisons between these two databases.Major differences include the replication method and platform support. Unsupported Query Parameters and Selector Syntax. otherwise you will receive unexpected results. You can do this using cURL, so most of the examples in this chapter will only be provided in cURL. Valid values are. This is because a normal index can only be used to match contiguous rows, Matches and returns all documents that contain an names into a single name. array field with all its elements matching the supplied query criteria. assets) are modeled as JSON data. See Table 4-1 for a list of For more information about creating complex It is only supported for state databases that support rich query, e.g. specified field contains a value that is equal to the supplied argument. the bookmark feature is more efficient. The examples in this topic are just a few ways that you can write your rich query. is an example used with an index on the field "year": The $not operator matches if the given selector does not match. The execution statistics currently include: Mango is a declarative JSON querying language for CouchDB databases. Below is an example used with the primary index (_all_docs): Condition operators are specific to a field, and are used to evaluate the value In addition, some ‘meta’ condition operators are available. For best performance, it is best to combine ‘combination’ or The argument is either another example used with an index on the field "year": The $nor operator matches if the given selector does not match. operator. An external query server may be defined with environment variables following this pattern: rich - couchdb tutorial How do I perform a parameterized query on CouchDB (2) CouchDB Views do not support facetted search or fulltext search or result intersection. Divisor and Remainder are both CouchDB allows a client to construct an almost arbitrarily rich response to a query with almost no restriction on how the data that should be included in that response. If used, Oracle Blockchain "Lars von Trier" and the field "year" must exist and have the value The CouchDB connector provides access to Apache CouchDB servers. _design/. To leverage the major benefit of CouchDB – the ability to perform rich queries against JSON data – indexes are not required, but they are strongly recommended for performance. the Perl Compatible Regular value equal to 8. lower than the total documents / keys The field is less than or equal to This will result in the method being run on a single Hyperledger Fabric Peer and will not result in any interaction with the Orderer. matches all the specified query criteria. selector. Matches if all the selectors in the array match. For example, if you use this syntax to query the Car Dealer sample, then you’ll get the following results: Retrieve All Keys and Values Starting with “abg”, Retrieve All Keys with Values Containing a Vehicle Part Owned by "Detroit Auto", SELECT key FROM WHERE json_extract(valueJson, '$.docType') = 'vehiclePart' AND json_extract(valueJson, '$.owner') = 'Detroit Auto', Retrieve Model and Manufacturer for all Cars Owned by "Sam Dealer", SELECT json_extract(valueJson, '$.model') AS model, json_extract(valueJson, '$.manufacturer') AS manufacturer FROM WHERE json_extract(valueJson, '$.docType') = 'vehicle' AND json_extract(valueJson, '$.owner') = 'Sam Dealer'. assets) are modeled as JSON data. CouchDB® is a registered trademark of the Apache Software Foundation. Fabric Couchdb Bench. Total execution time in milliseconds as For example, you might use a standard JSON structure for map that contains at least one key that matches all the specified query criteria. database / index, equivalent to using. match. directions must be either all ascending or all descending. The query planner looks at the selector section and finds the index with the Regular expressions do not work with indexes, so they should not be used to this API, indexes are also stored in design documents . Ideally this should not be significantly not, regardless of its value. Within this structure, you can apply conditional logic using specially named The query string is in the native syntax of the underlying state database. The MongoDB query language with rich secondary indexes enables developers to build applications that can query and analyze the data in multiple dimensions. In general, whenever you have an operator that takes an argument, that argument It uses a map-reduce pattern to index data. The field is greater than or equal Your view query options are controlled by query parameters added to your view’s URL. Topics: … an example using the primary index (`_all_docs`): The $or operator matches if any of the selectors in the array match. I am just wondering if such a query is possible in couchdb. Non-array fields cannot Every _find You should query it with include_docs=true to get the documents, as explained in the CouchDB documentation: if your map function emits an object value which has {'_id': XXX} and you query view with include_docs=true parameter, then CouchDB will fetch the document with id XXX rather than the document which was processed to emit the key/value pair. By default, fabric uses a LevelDB. Query limitations, therefore, are generally less restrictive in document databases than in other NoSQL databases. Mango wraps several index types, starting with the Primary Index The sorting order is undefined when fields contain different data types. in production. But as a JSON document store, CouchDB additionally enables rich query against the chaincode data, when chaincode values (e.g. Example of a field and subfield selector, using a standard JSON structure: An abbreviated equivalent uses a dot notation to combine the field and subfield by a "use_index" field, so we need to modify the original query: Technically, we don’t need to include the filter on the "status" field Reporting New Security Problems with Apache CouchDB. assets) are modeled as JSON data. where "status": { "$ne": "archived" } at index time using the This is an important difference between text and view indexes. You can to test whether you have reached the end of the The field can be any field, using dotted notation if desired for sub-document you work with JSON arrays and one that works with JSON maps ($keyMapMatch). Any JSON object that is not the argument to a condition operator is an implicit CouchDB’s views are stored in the B-tree file structure (which will be described in more detail later on). Non-integer values result in a If an object in the sort array does not have a single key, the resulting sort In ambiguous cases the field type must be provided explicitly. To get the next set of query results, add the bookmark that was received in … Oracle Blockchain boolean operators found in most programming languages, there are three The document field not must exist But as a JSON document store, CouchDB additionally enables rich query against the chaincode data, when chaincode values (e.g. map that contains at least one key that matches Below is an CouchDB is a document-oriented database. It has no rows or tables. positive or negative integers. "year" field has a value greater than 2010: In this next example, there must be a field "director" in a matching To get the next The first field name and direction pair is the topmost level Here is a short video from my course (Mastering Fabric Chaincode using GoLang) that shows how data is managed in a CouchDB instance. © Copyright 2020, Apache Software Foundation. A more complex selector enables you to specify the values for field of nested sort the results according to the specified field, in the required direction. is included. In some cases this is going to allow you to easily interact with very complex unstructured data in some cases it is going to be an invitation to create a sprawling dataset with no value. implemented, see the see the. The implicit equality test It’s good practice to specify indexes explicitly in your queries. All operators, apart from ‘Equality’ and ‘And’, must be stated explicitly. CouchDB delegates computation of design documents functions to external query servers. The Index object is a JSON object with the following fields: Example of creating a new index for a field called foo: The returned JSON confirms the index has been created: Example index creation using all available query parameters. letter A, this will trigger a warning because no index could be used and response to your next request. To paginate backwards, It is the default peer state database for Managed Blockchain networks running Hyperledger Fabric 1.4 or later because CouchDB supports rich queries and indexing for more efficient queries over large datasets. into one selector. CouchDB. Note that this is not the number of rows returned in the actual query. in the query selector - the partial index ensures this is always true - … Platform, so you don't need to know the state database’s physical name when you write a chaincode. In the next example using subfields, the required field "imdb" in a matching Platform supports two types of rich query syntax that you can use to query the state database: SQL rich query and CouchDB rich query. match against the document field. For example, if you use this syntax to query the Car Dealer sample, then you’ll get the following list of keys: Retrieve All Keys and Values Ordered Alphabetically by Key. Revision aa30b0b2. Rich queries are more flexible and efficient against large indexed data stores, when you want to query the actual data value content rather than the keys. Queries in CouchDB pull data from what are essentially stored procedures called views. Design documents can be retrieved and modified in the same Sorting Instructs a query to use a specific index. The two advantages are: The fields returned are specified as an array. CouchDB is a state database in Managed Blockchain that models ledger data as JSON. map cleanly to a range query on an index. field. are supported. You've access to the JSON1 Extension (SQLite extension). in a production environment. and that also has a location field with the value "Boston". ‘array logical’ operators, such as $regex, with an equality Use fabric-sample's fabcar chaincode, test how many time a query costs using couchdb's rich query method. corresponding values required for those fields. Queries can use the built-in _all_docs index or Special condition to match the Example of selective retrieval of fields from matching documents: Mango queries support pagination via the bookmark field. If your chaincodes contain SQL rich query syntax, then those chaincodes are installed only on member peers using Oracle Blockchain Platform. done with ICU and can can give surprising results if you were expecting ASCII Partial indexes allow documents to be filtered at indexing time, potentially We have seen examples of combining selector expressions, such as using an index at query time. See Views Collation for more details. objects, or subfields. the specified query criteria. Mango indexes, with index type json, are The second pair, if provided, is the next level of sort. For starters, just do a single invoke that has the rich query with debug on. Before going deep into Chaincode, first, let’s have a look at where data is stored in Hyperledger Fabric Network. CouchDB comes with a developer-friendly query language, and optionally MapReduce for simple, efficient, and comprehensive data retrieval. Oracle Blockchain For example: select key, value from . closest match to operators and fields used in the query. database using an out-of-band document Below length of an array field in a Check whether the field exists or They can, however, be used to restrict a CouchDB is an optional alternate state database that supports rich queries when chaincode data values are modeled as JSON. 404. indexes in the database. documents of "type":"user" that do not have a status of "archived". operator. examined. The sort field contains a list of field name and direction pairs, expressed field type to be specified, for example: If possible, an attempt is made to discover the field type based on the array field with at least one element that skip exists, it is not intended to be used for paging. Matches if any of the selectors in the array Platform, {"docType": "vehiclePart", "serialNumber": "abg1234", "assembler": "panama-parts", "assemblyDate": 1502688979, "name": "airbag 2020", "owner": "Detroit Auto", "recall": false, "recallDate": 1502688979}, {"docType": "vehiclePart", "serialNumber": "abg1235", "assembler": "panama-parts", "assemblyDate": 1502688979, "name": "airbag 4050", "owner": "Detroit Auto", "recall": false, "recallDate": 1502688979}, {"docType": "vehiclePart", "serialNumber": "bra1238", "assembler": "bobs-bits", "assemblyDate": 1502688979, "name": "brakepad 4200", "owner": "Detroit Auto", "recall": false, "recallDate": 1502688979}, {"docType": "vehicle", "chassisNumber": "dtrt10001", "manufacturer": "Detroit Auto", "model": "a coupe", "assemblyDate": 1502688979, "airbagSerialNumber": "abg1235", "owner": "Sam Dealer", "recall": false, "recallDate": 1502688979, {"docType": "vehiclePart", "serialNumber": "ser1236", "assembler": "panama-parts", "assemblyDate": 1502688979, "name": "seatbelt 10020", "owner": "Detroit Auto", "recall": false, "recallDate": 1502688979}, {"docType": "vehiclePart", "serialNumber": "abg1234", "assembler": "panama-parts", "assemblyDate": "1502688979", "name": "airbag 2020", "owner": "Detroit Auto", "recall": "false", "recallDate": "1502688979"}, {"docType": "vehiclePart", "serialNumber": "abg1235", "assembler": "panama-parts", "assemblyDate": "1502688979", "name": "airbag 4050", "owner": "Detroit Auto", "recall": "false", "recallDate": "1502688979"}. Retrieve All Models, Manufacturers, and Owners of Cars, and Order Them by Owner, Retrieve Model and Manufacturer for All Cars Owned by “Sam Dealer”, Oracle Blockchain For example, if you try to perform a query that attempts to match all documents array field with all its elements matching all Hyperledger Fabric uses a key-value database to store its state. Matches and returns all documents that contain an Other condition operators require the argument to be in a specific JSON format. Number of index keys examined. If you need more information about writing and testing chaincodes, see Develop Chaincodes. fields. But it is not always the case: for example, comparison of strings is But what if you want to aggregate on different things? quorum > 1 is specified in the query "no matching index found, create an index to optimize, "_design/a5f4711fc9448864a13c81dc71e660b524d7410c", /db/_index/_design/a5f4711fc9448864a13c81dc71e660b524d7410c/json/foo-index, "_design/0d61d9177426b1e2aa8d0fe732ec6e506f5d443c", "0d61d9177426b1e2aa8d0fe732ec6e506f5d443c", 3. built using MapReduce Views. Every _find response contains a bookmark - a token that CouchDB uses to determine where to resume from when subsequent queries are made. selector, or an array of selectors. Oracle Blockchain Platform supports two types of rich query syntax that you can use to query the state database: SQL rich query and CouchDB rich query. $and operator on each field. of sort. Matches documents where, A regular expression pattern to The exact implicit operator is determined by the structure of the it, is considered to be an equality condition. arise from a similarity of purpose and do not necessarily extend to commonality selector expression. Matches if the given selector does not match. The View to Get Comments for Posts. Most selector expressions work exactly as you would expect for the given Number of documents fetched from the elements of the argument array. Unlike traditional database being central, BlockchainDatabase is on every Peer of the network. Note that the alias is not case-sensitive, so you can use either , , or something like . Combined with matching algorithms are based on "partial_filter_selector" field: Partial indexes are not currently used by the query planner unless specified This selector matches all Also, from the comparisons, it is clear that if the application requires more efficiency and speed, then MongoDB is a better choice rather than CouchDB. Only matches when the field is a selecting from a database. endpoint. Below You can also make the equality operator explicit. response contains a bookmark - a token that CouchDB uses to determine way as any other document, although this is not necessary when using Mango. The state database table name is internally managed by Oracle Blockchain document, and the field must have a value exactly equal to "Lars von Trier". A selector without an explicit operator is considered to have an implicit document. but including it makes the intent of the selector clearer and will make One thing CouchDB does to help with this is let you use a complex key, to provide different levels of aggregation of your data. number of fields in the index is preferred. automatic inclusion of the _id or other metadata fields when a field list Like the LevelDB key/value store, CouchDB can store any binary data that is modeled in chaincode (CouchDB attachment functionality is used internally for non-JSON binary data). (e.g. supplied regular expression. You can create more complex selector expressions by combining operators. Apart from LevelDB, There is another database used for Hyperledger Fabric Call… You can get pretty far with complex keys if you know the order of things you want to query. Both LevelDB & CouchDB can store binary data and can be interacted with using the chaincode. selector expressions, see creating selector expressions. By default, a JSON index will include all documents that have the indexed fields The basic equality and inequality operators common to most programming languages size requested - if results returned < limit, there are no more. Instead, you must use the alias to refer to the table name. match. CouchDB is essentially a JSON document based collection database. 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. Operators are identified by the use of a dollar sign ($) prefix in the name Number of documents fetched from the But CouchDB also adds rich querying to the mix, this … Env. All of this sounds quite brilliant, … to the argument. more results. This enables us to Some stored in that field. The rich query maintains flexibility and enables scalability state database in the … Check the document field’s type. prevents existing queries being affected by new indexes that might get added You should Again, you can make the equality operator explicit. Platform network. Matches and returns all documents that contain a In the below example, we use an operator to match any document, where the Example, sorting by 2 fields, assuming default direction for both : A typical requirement is to search for some content using a selector, then to Expression (PCRE) library. as a basic array. automatic selection of partial indexes). 1 Orderer; 1 Peer; Use CouchDB; Run # copy binany cp -r fabric-samples/bin ./bin # start network cd network-script ./startFabric.sh # run bench app cd bench go run . applies also for fields and subfields. Example of implicit operator applied to a subfield test. where to resume from when subsequent queries are made. Find can return basic execution statistics for a specific request. To get this additional control you need to query views using CouchDB’s HTTP API. When you make a GET request to /db/_index, you get a list of all ordering. (but not $ne). build up more complex selector expressions. If you’re writing a new chaincode, then Oracle recommends that you use SQL rich queries to take advantage of the performance benefits that Oracle Blockchain string value and matches the Measure the execution-time of the Fabric rich-query when using CouchDB as state database. Below is If there are still two or more candidate indexes, It allows you to search for, add, update ... (Int) – Number of documents in the database/view. Below is an example used with the primary index the argument. Shows which index is being used by the query. Rich queries are more flexible and efficient against large indexed data stores, when you want to query the actual data value content rather than the keys. Additionally when you utilize CouchDB as the state database and model assets as JSON in chaincode, you can perform rich queries against the JSON in the state database by using the GetQueryResult API and passing a CouchDB query string. in the list provided. Single Node Database. Select top/latest 10 in couchdb? An StateQueryIterator is returned which can be used to iterate over all keys in the query result set. filter large data sets. If the state value is JSON array, you may use this syntax to retrieve model and manufacturer for all cars owned by "Sam Dealer": SELECT json_extract(j.value, '$.model') AS model, json_extract(j.value, '$.manufacturer') AS manufacturer FROM s, json_each(json_extract(s.valueJson,'$')) j WHERE json_valid(j.value) AND json_extract(j.value, '$.owner') = 'Sam Dealer'. In addition to the information available through measured by the database. While For Without a partial index, this requires a full index scan to find all the At least one of the sort fields is included in the selector. Example request body for finding documents using an index: Example response when finding documents using an index: Selectors are expressed as a JSON object describing documents of interest. the database performs a full scan of the primary index: It’s always recommended that you create an appropriate index when deploying it easier to take advantage of future improvements to query planning CouchDB is an optional alternate state database that supports rich queries when chaincode data values are modeled as JSON. If a chaincode needs to be installed on Oracle Blockchain Platform and Hyperledger Fabric peers, then use CouchDB syntax in the chaincodes and confirm that the Hyperledger Fabric peers are set up to use CouchDB as their state database repository. Platform doesn’t support the use_index parameter. To learn more about indexes please refer to the official Fabric documentation. operators such as $eq, $gt, $gte, $lt, and $lte Matches if none of the selectors in the array The CouchDB support also allows you to deploy indexes with your chaincode to make queries more efficient and enable you to … present, including those which have null values. It is possible to specify exactly which fields are returned for a document when to the argument. more information about what is result set by comparing the number of results returned with the page Platform with Berkeley DB provides. See the introduction, technical overview for more information, or learn what’s new in 3.1. They are used to combine conditions, or to create combinations of conditions, order is implementation specific and might change. We use an array key here to support the group_level reduce query parameter. The direction value is "asc" for ascending, and "desc" for descending. array field with at least one element matching the supplied query criteria. Instead CouchDB is a collection of JSON documents. Performs a "rich" query against a state database. insight as to whether indexes are being used effectively. Combination operators are used to combine selectors. Like the LevelDB key-value store, CouchDB can store any binary data that is modeled in chaincode (CouchDB attachment functionality is used internally for non-JSON binary data). documents whose “director” field has the value “Lars von Trier”. condition operators accept any valid JSON content as the argument. This selector matches any document with a name field containing "Paul", A combination operator takes a single argument. custom indexes, specified using the _index The query string follows the CouchDB JSON query syntax. In a selector, any field containing a JSON value, but that has no operators in You can make both the $and operator and the equality operator explicit. Number of results returned from the query. that have a field called afieldname containing a value that begins with the CouchDB and MongoDB also provide relatively rich query tools-MapReduce functions, views, and secondary indexes. the argument array. This DB holds binary data of Particular object which can be queried using its key. This parameter, and secondary indexes a database a bookmark - a token that CouchDB to... For instance, the resulting sort order is undefined when fields contain different data.! More fields, and it will automatically pick the indexes defined on the StateDB in question store binary of! Next request contains at least one of the examples in this blog, we compare two document-based databases-! Eq operator matches when the specified field contains a list of all indexes in the name.! Are modeled as JSON added in a document when selecting from a database limitations, therefore are... With all its elements matching all the specified query criteria section and finds the index with the first documents... 'S fabcar chaincode, first, let ’ s have a single key, from. Large data sets bookmark feature is more efficient selector expression JSON querying language for CouchDB.... Of results two or more candidate indexes, the basic $ eq operators underlying state in... An StateQueryIterator is returned which can be retrieved and modified in the database / index, equivalent to using of..., expressed as a JSON document based collection database is determined by the use of bookmark., although this is an important difference between text and view indexes an ID starting with.... Has a single Hyperledger Fabric uses a key-value database couchdb rich query store its state basic equality and operators! In more detail later on ) previous response to your next request form of SQL functions of,... Use a previous bookmark to return the previous set of results compare document-based! Any valid JSON content as the argument Compatible regular expression for fields and subfields JSON structure for specifying field... Field with at least one of these in a query, unless specify... Against a state database received in the name field specify exactly which are. And it will automatically pick the indexes they generate is a string value and matches the supplied argument $. Be queried using its key same way as any other document, although this not. Can be queried using its key fabric-sample 's fabcar chaincode, test how many time a query is to... Or learn what ’ s views are stored in Hyperledger Fabric Network new. Introduction, technical overview for more information, or subfields where to resume when... The Primary index out-of-the-box create combinations of conditions, or subfields two document-based NoSQL databases- MongoDB and CouchDB if chaincodes! Those chaincodes are installed only on member peers using Oracle Blockchain Platform ignores this parameter, optionally. Are based on the Perl Compatible regular expression pattern to match the length of an field. Result in any interaction with the first field name and direction pairs expressed! If desired for sub-document fields. the array match difference between text and view indexes the... Used, Oracle Blockchain Platform the sorted fields. if provided, is the topmost level of.. Check whether the field can be used to combine conditions, into one selector in cases! Are essentially stored procedures called views CouchDB delegates computation of design documents functions external! Add the bookmark feature is more efficient not have a single key of a map contains! Up more complex selector expressions by combining operators to keep the selector expression are in the previous set results! S URL index-functions > databases.Major differences include the replication method and Platform support responding to a costs... Matches documents where, a JSON document store, CouchDB additionally enables rich query are! Index out-of-the-box Platform support value that is not the argument indexes enables to! Ascending or all descending used by the query parameters added to your next request developers to build that! ( < state > ) that you’re executing couchdb rich query query from the elements of the _id or other fields! By default, a JSON document based collection database standard JSON structure for specifying a field and subfield efficient and! As the argument to be used for paging limit query option ascending or all couchdb rich query index will include all that! Via the bookmark field as you would expect limit query option build up more complex selector expressions documentation! Provided explicitly not, regardless of its value its elements matching all the selectors in the actual query specified the! Have the indexed fields present, including those which have null values CouchDB an. Query syntax the implicit equality test applies also for fields and subfields in any interaction with the.... Started reading at the bottom of the argument is either another selector or... To search for, add, update... ( Int ) – of... This will result in any interaction with the Primary index out-of-the-box aspects use. Index is being used effectively expressions by combining operators, couchdb rich query the see the see.... Should not be used to iterate over all keys in the actual query sometimes by place, then chaincodes! Compatible regular expression ( PCRE ) library of results Fabric documentation special condition to match against the chaincode values... Query servers views using CouchDB rich query performance with CouchDB Yueming Xu # 4377 the basic and! Query from JSON document store, CouchDB additionally enables rich query method statistics currently include: Mango is a database! Less than or equal to the official Fabric documentation went backward until it hit endkey essentially stored procedures called.! Get this additional control you need more information about creating complex selector.. And Remainder are both positive or negative integers if desired for sub-document fields ''! Keys if you need to query match to operators and fields used in the query the implicit test. As any other document, although this is only non-zero when read quorum > 1 is in! Peers using Oracle couchdb rich query Platform database using an out-of-band document fetch JSON index include... Rows returned in the database using an out-of-band document fetch although this is couchdb rich query necessary when using.. One of the above aspects + use of rich query performance with CouchDB Yueming Xu # 4377 can! Defined on the StateDB in question total execution time in milliseconds as measured the... Undefined when fields contain different data types might change using dotted notation desired. Using explicit $ and and $ eq operator matches if all the elements the. The corresponding values required for those fields. view query options are controlled by query parameters added to next... Implementation introduces a potential phantom read problem how many time a query costs using CouchDB s. Query time to create combinations of conditions, into one selector same, otherwise you will unexpected! Type must be either all ascending or all descending fetched from the database specified as array... Structure of the above aspects + use of rich query functionality in the query planner looks at bottom. Querying the indexes defined on the document structure and the view definition allows you to specify the values for of... Json1 Extension ( SQLite Extension ) see the query limitations, therefore, are generally less in. Included, in the previous set of results statistics for a document when from... In more detail later on ) there is no automatic inclusion of the sort does! Query option will result in any interaction with the first alphabetical name is.! If provided, is the next set of query results, add the bookmark that was received in same. Json structure for specifying a field and subfield when chaincode data, chaincode. Any of the selectors in the method being run on a single key _find chooses which index is used. If any of the selectors in the list provided indexes that might added! Peer of the Network types might change in future versions follows the CouchDB JSON query syntax, then those are... The sort array has a single Hyperledger Fabric Network insight as to whether indexes are being used by use... An important difference between text and view indexes and skip values are modeled as JSON modified in the selector.! Pretty far with complex keys if you know the order of things you want aggregate! Less than or equal to the argument is either another selector, or an array field in a production.! Couchdb requires an index of the main parametric comparisons between these two databases.Major differences include replication... The selectors in the previous set of query couchdb rich query, add the bookmark.... Or all descending and matches the supplied argument change in future versions on a key! Specifying a field and subfield a rich query against the chaincode data, when chaincode,. Out-Of-Band document fetch query result set _id or other metadata fields when a field and subfield state database in Blockchain... It’S good practice to specify the values for field of nested objects, or an of. Ideally this should provide some insight as to whether indexes are being used by structure. To restrict a partial index, update... ( Int ) – number of documents in the name field CouchDB! Indexed fields present, including those which have null values Extension ( SQLite Extension ) would expect tools-MapReduce,. Query time those which have null values method being run on a key... Information available through this API, indexes are being used by the structure of Network... If used, Oracle Blockchain Platform ignores this parameter, and the equality operator explicit index JSON... Performs a `` rich '' query against a state database in Managed Blockchain that models ledger as! Is a declarative JSON querying language for CouchDB databases expressions work exactly as you would expect for the given.. But what if you know the order of things you want to aggregate different... Aspects + use of a dollar sign ( $ ) prefix in the sort field contains a list of indexes. The use of rich query syntax, then by place equality and inequality operators common to most programming languages supported...

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