nosql

Redis(一)

由 拜拜、爱过 提交于 2019-12-06 03:36:35
1 单机MySQL的美好时代 2 Memcached(缓存)+MySQL+垂直拆分 3 MySQL主从读写分离 4 分库分表+水平拆分+mysql拆分 5 MySQL的扩展瓶颈 6 为什么使用NoSQL NoSQL的特性 NoSQL数据库种类繁多，但是一个共同的特点就是去掉关系型特性 数据之前无关系，这样就非常容易扩展，也无形之间，在架构的层面带来了可扩展的能力 大数据量高性能 NoSQL数据库都具有非常高的读写性能，尤其在大数据量下，同样表现优秀 这得益于它的无关系性，数据库的结构简单 一般MySQL使用Query Cache，每次表的更新Cache就会失效一次，是一种大粒度的Cache 在针对web2.0的交互频繁的应用，Cache性能不高，而NoSQL的Cache是纪录级 是一种细粒度的Cache，所以NoSQL在这个层面上来说就要性能高很多了。 多样灵活的数据模型 NoSQL无需事先为要存储的数据建立字段，随时可以存储自定义的数据格式，而在关系数据库里，增删字段是一件非常麻烦的事情，如果是非常大数据量的表，增加字段简直就是一个噩梦。 RDBMS vs NoSQL RDBMS 高度组织化结构化数据 结构化查询语言(SQL) 数据和关系都存储在单独的表中 数据操纵语言，数据定义语言 严格的一致性 基础事务 NoSQL 代表着不仅仅是SQL 没有声明性查询语言 没有预定义的模式

How would you model customer > order > ordertem > product in NoSql database?

由 一世执手 提交于 2019-12-06 03:19:33
问题 I'm currently learning Node.JS and need to implement a database. All of the Node books seem to think MongoDB is the best solution but I can't seem to get my head around NoSql databases like Mongo and Couch, I'm an MS SQL Server guy! So, I understand that you can keep structured data as records (JSON) but I'm not sure how you'd model a typical ecommerce app with the following (simplified) tables... customers (id, name, address) orders (id, customerID, orderDate) orderItems (id, orderID,

Which noSQL database is best for high volume inserts / writes?

由 风格不统一 提交于 2019-12-06 03:02:35
问题 Which nosql system is better equipped for handling high volume inserts out of the box? Preferably, running on 1 physical machine (many instances allowed). Has anyone done any benchmarks? (googling did not help) Note : I understand that choosing noSQL database depends on what kind of data needs to be stored (document:MongoDB, graph:Neo4j, etc.). 回答1: Apache Cassandra is great in write operations, thanks to its unique persistence model. Some claim that it writes about 20 times faster than it

Write heavy, replicated, bigger-than-memory key-value store

由 跟風遠走 提交于 2019-12-06 02:50:00
问题 I'm looking for a key value store that can be used from an EC2 instance. item is just an unstructured string, no indexing required item size up to ~5MB but usually below 10kB lots of writes reading doesn't need to be fast, memcache can be put in front that caches frequently needed reads data is too big to fit into memory Eventual Consistency is fine daemon that can be accessed from multiple machines is required Ideally something AWS hosted would be perfect but: S3 doesn't fit because of too

Knowledge sources for Apache Cassandra

由 心已入冬 提交于 2019-12-06 02:49:28
问题 I'm planning to start project with NoSQL for data storage. I was trying to find informations about Cassandra in google but I've found very basic info. Anyone know where I can find good source of knowledge about Cassandra (planing data structure, working with data (maybe migrating from mysql?) etc)? 回答1: DataStax has comprehensive Cassandra documentation at http://www.datastax.com/docs/1.0/index. "Cassandra High Performance Cookbook" is a decent book. O'Reilly's "Definitive Guide" is actually

Join two collections with MapReduce in MongoDB

由 ￡可爱￡侵袭症＋ 提交于 2019-12-06 02:36:25
I already know that MongoDB doesn't support join operations, but i have to simulate a $lookup (from the aggregation framework) with the mapReduce paradigm. My two collections are: // Employees sample { "_id" : "1234", "first_name" : "John", "last_name" : "Bush", "departments" : [ { "dep_id" : "d001", "hire_date" : "date001" }, { "dep_id" : "d004", "hire_date" : "date004" } ] } { "_id" : "5678", "first_name" : "Johny", "last_name" : "Cash", "departments" : [ { "dep_id" : "d001", "hire_date" : "date03" } ] } { "_id" : "9012", "first_name" : "Susan", "last_name" : "Bowdy", "departments" : [ {

Doing range queries in Mongoose for Hour / Day / Month/ Year

由 你离开我真会死。 提交于 2019-12-06 02:28:02
问题 Trying to figure out how to do this. Basically I want to sort by Hour / Day / Month / Year of my submissions. Each submission has a created field which contains a Mongoose Date object in the form of "created" : ISODate("2013-03-11T01:49:09.421Z") . Do I need to compare against this in the find() conditions? Here is my current query (I'm wrapping it in a count for pagination purposes FWIW so just ignore that part): getSubmissionCount({}, function(count) { // Sort by the range switch (range) {

AWS Dynamodb: Is it possible to make a query only using sort key

由 别来无恙 提交于 2019-12-06 02:23:36
问题 Hi dynamodb community, So the table in question is MLA_USER_AUTH. As you see it has as partition key and as sort key. I want to be able to query the database using both user_id and email. Sometimes I need to find the user associated with the email and sometimes the userid. Both email and userid attributes are unique for every visitor. is there any way it can be done? This is my current query. This obviously doesnt work. As it throws the error: ValidationException: Query condition missed key

Stored procedure in Neo4j

由 帅比萌擦擦* 提交于 2019-12-06 02:16:44
问题 I wanted to know if there is any Neo4j equivalent of a stored procedure? When I researched this, I came across events , but I found them more like triggers and not stored procedures. 回答1: Stored procedures are available as capabilities CALLABLE from the Cypher language since version 3.0 A first reference can be found here https://dzone.com/articles/neo4j-30-stored-procedures A remarkable example, showing how graph can be processed in the large through procedure to achieve network clustering

How to: SQL or NOSQL?

由 梦想与她 提交于 2019-12-06 01:46:42
I haven't been confronted with this yet, but this is what i think (very superficial and simplistic imho) If you have a key value kind of storage and all you accesses are key lookups use the NOSQL solutions. If you want lookups based on values (and subvalues) or have something more complicated like joins you would go for a relational solution. Transactions = relational (am not too sure if nosql solutions support that notion yet) It also looks like NOSQL = denormalized (SQL) (i may be terribly mistaken here) In general, any principles/guidelines/thumb rules to decide chosing the data model for
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