nosql

NoSQL database design for queries with multiple restrictions (Firebase)

由 家住魔仙堡 提交于 2019-12-18 09:46:19
问题 I need best practice tips to enhance the performance of my noSQL database (hosted on Firebase). Moreover, I need tips on how to structure the nodes. The database stores product information, with three main properties: $productId /date /category /subcategory On my website, I have three views: retrieve the last 4 products (orderBy date) retrieve last 4 products (by date) of category X retrieve last 4 products (by date) of category X and subcategory Y. Note that I also have a node product_images

Hbase auto increment any column/row-key

由 自闭症网瘾萝莉.ら 提交于 2019-12-18 09:28:19
问题 I am new to Hbase is it possible to/how can I auto increment row-key in Hbase? (like for each insert row-key has to be auto increment itself) or is it possible to auto-increment any other column ? (like for each insert this column has to be auto-increment by 1) 回答1: Monolitically increasing row keys are not recommended in HBase, see this for reference: http://hbase.apache.org/book/rowkey.design.html, p.6.3.2. In fact, using globally ordered row keys would cause all instances of your

Serialising an object to JSON, and then using that to send a query in elastic search using NEST

由 走远了吗. 提交于 2019-12-18 09:25:40
问题 I get a bit confused and frustrated when it comes to using NEST to querying, as it seems very hit and miss. I have no trouble querying when using standard JSON, so I was wondering if there was some way to query using a JSON object, I have code below var query = "bkala"; var q = new { query = new { text = new { _all = "jane" } } }; var qJson = JsonConvert.SerializeObject(q); var hits = client.Search<Users>(qJson); However, I get the error "Cannot convert from type string to System.Func, Nest

MongoDB lookup when foreign field is an array of objects

由 六月ゝ 毕业季﹏ 提交于 2019-12-18 09:14:56
问题 I have two collections initiatives and resources : initiative document example: { "_id" : ObjectId("5b101caddcab7850a4ba32eb"), "name" : "AI4CSR", "ressources" : [ { "function" : ObjectId("5c3ddf072430c46dacd75dbb"), "participating" : 0.1, }, { "function" : ObjectId("5c3ddf072430c46dacd75dbc"), "participating" : 5, }, { "function" : ObjectId("5c3ddf072430c46dacd75dbb"), "participating" : 12, }, { "function" : ObjectId("5c3ddf072430c46dacd75dbd"), "participating" : 2, }, ], } and a resource

How can we ensure Data integrity in mongoDb?

由 余生颓废 提交于 2019-12-18 07:39:50
问题 i am trying to migrate from relational database (mysql) data to nosql (mongoDb) . But how can i ensure data integrity in mongodb . what i have found that we cannot do it on server side. what should i use on application side to handle data integrity ? For eg: i have two tables user and task . Both have userId field common . if i add a new entry in task table it should check if userid present in user table. this is one of the requirement others like adding constraints , updating values etc 回答1:

How to structure NoSQL messages to get unreads by 1 query?

由 别等时光非礼了梦想. 提交于 2019-12-18 07:19:04
问题 Say I have NoSQL structure as follows: messages chat_id (known) message_id (generated automatically) {author, timestamp, content} I also have users/ branch where I can see last logins of both users involved. I want to get the number of unread messages for a given user by 1 query. How would you implement such a task? 回答1: There are two parts to this problem: Counting the number of messages Tracking what a user has read Counting the number of messages Assuming you are using the Firebase

Too many open files while ensure index mongo

由 强颜欢笑 提交于 2019-12-18 04:52:32
问题 I would like to create text index on mongo collection. I write db.test1.ensureIndex({'text':'text'}) and then i saw in mongod process Sun Jan 5 10:08:47.289 [conn1] build index library.test1 { _fts: "text", _ftsx: 1 } Sun Jan 5 10:09:00.220 [conn1] Index: (1/3) External Sort Progress: 200/980 20% Sun Jan 5 10:09:13.603 [conn1] Index: (1/3) External Sort Progress: 400/980 40% Sun Jan 5 10:09:26.745 [conn1] Index: (1/3) External Sort Progress: 600/980 61% Sun Jan 5 10:09:37.809 [conn1] Index:

“IN” statement in dynamodb

由 十年热恋 提交于 2019-12-18 04:04:10
问题 I have a "Users" table, here is a sample : { username:"haddox", formattedPhoneNumber:"676767676", verified: 0, } My wish is to retrieve all users whose formattedPhoneNumber is contained in an array of phone numbers (retrieved from my contacts). I created a secondary index, with verified as HASH and formattedPhoneNumber as RANGE. Here is my try : var params = { TableName: "Users", IndexName: "FormattedPhoneSecondaryIndex", KeyConditionExpression: "verified = :v AND formattedPhone IN :n",

WHERE clause on an array in Azure DocumentDb

由 岁酱吖の 提交于 2019-12-18 01:33:21
问题 In an Azure Documentdb document like this { "id": "WakefieldFamily", "parents": [ { "familyName": "Wakefield", "givenName": "Robin" }, { "familyName": "Miller", "givenName": "Ben" } ], "children": [ { "familyName": "Merriam", "givenName": "Jesse", "gender": "female", "grade": 1, "pets": [ { "givenName": "Goofy" }, { "givenName": "Shadow" } ] }, { "familyName": "Miller", "givenName": "Lisa", "gender": "female", "grade": 8 } ], "address": { "state": "NY", "county": "Manhattan", "city": "NY" },

MYSQL:NoSQL(Redis服务)

由 拈花ヽ惹草 提交于 2019-12-18 00:55:41
文章目录 NoSQL相关概念 RDBMS NoSQL 部署Redis服务器 Redis介绍 源码编译安装 初始配置 服务基本使用 管理服务 连接服务 Redis常用命令 配置文件解析 配置分类 常用配置 内存管理 修改Redis服务运行参数 与网站服务一起使用(LNMP+Redis) 部署LNMP环境 在主机192.168.4.57部署LNMP环境 配置PHP支持redis NoSQL相关概念 RDBMS 关系数据库管理系统 － R elational D ata b ase M anagement S ystem －按照预先设置的组织结构,将数据存储在物理介质上 －数据之间可以做关联操作 主流的RDBMS软件 －MySQL －MariaDB －Oracle －DB2 －SQL Server NoSQL NoSQL=Not Only SQL －意思是"不仅仅是SQL" －泛指非关系型数据库 －不需要预先定义数据存储结构 －每条记录可以有不同的数据类型和字段个数 主流软件 －Memcached －Redis －MongoDB －CouchDB －Neo4j －FlockDB 部署Redis服务器 Redis介绍 － R emote D ictionary S erver －是一款高性能的(Key/Values)分布式内存数据库 －支持数据持久化(定期把内存里数据存储到硬盘)
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