77 lines
2.8 KiB
Markdown
Executable File
77 lines
2.8 KiB
Markdown
Executable File
# 数据库
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```
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KISS - Keep It Simple & Stupid；
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```
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数据被快速制造和消费，数据看上去更加无秩序，或叫非结构化，据说超过80%，且持续加速增加，于是新的非关系型DB/noSQL快速崛起
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#### :question:
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- 类型
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- 特点
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- 选型
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#### 数据库类型
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```
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- Relational DBMS
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- oracle,mysql,postgreSQL,hive
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- Key-value stores
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- redis,memcached
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- Document stores/document-oriented database
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- Graph DBMS
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- neo4j,Microsoft Azure Cosmos DB
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- Time Series DBMS
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- InfluxDB,Kdb+,Prometheus,Graphite,RRDtool,OpenTSDB,Druid
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- Object oriented DBMS
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- RDF stores
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- Search engines
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- Elasticsearch,Splunk
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- Wide column stores
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- Cassandra,hbase
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- Multivalue DBMS
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- Native XML DBMS
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- Event Stores
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- Content stores
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- Navigational DBMS
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```
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#### Document stores database
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also called document-oriented database systems, are characterized by their schema-free organization of data.
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Records do not need to have a uniform structure, i.e. different records may have different columns.
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The types of the values a€?a€?of individual columns can be different for each record.
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Columns can have more than one value (arrays).
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Records can have a nested structure.
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Document stores often use internal notations, which can be processed directly in applications, mostly JSON.
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JSON documents of course can also be stored as pure text in key-value stores or relational database systems.
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That would, however, require client-side processing of the structures, which has the disadvantage that the features offered by document stores (such as secondary indexes) are not available.
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<br>存储文档数据库，也叫面向文档数据库，主要特点是非结构化、数据的自由组织
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纪录可以非结构化，比如不同纪录中的可以有不同的列，不同列的数据类型也可以不同，列的数据可以是多个值，比如一个array，记录还可以是嵌套结构。
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比如方便直接存储JSON数据，key-value数据库也可以存储JSON数据，但客户需要自己处理数据结构，这样就容易失去JSON数据组织的优点，比如第二个索引
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#### kafka & redis
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## 消息系统
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:question:
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- 异步
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- 解耦
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- 顺序
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kafka通过zookeeper来存储集群的meta信息
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[Redis哨兵模式（sentinel）学习总结及部署记录（主从复制、读写分离、主从切换）](https://www.cnblogs.com/kevingrace/p/9004460.html)
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#### references
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1. [db ranking](https://db-engines.com/en/ranking)
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1. [influxDB vs. openTSDB](http://blog.fatedier.com/2016/07/06/test-influxdb-and-opentsdb/)
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1. [openTSDB](http://blog.fatedier.com/2016/07/04/research-of-time-series-database-opentsdb/)
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1. [恒丰银行——大数据实时流处理平台](http://www.sohu.com/a/148106853_400678)
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