最新消息:网盘下载利器JDownloader--|--发布资讯--|--站务--|--解压出错.密码问题--

An Overview of NoSQL Databases

网络技术 killking 0评论
An Overview of NoSQL Databases

An Overview of NoSQL Databases

HDRips | MP4/AVC, ~856 kb/s | 1280x720 | Duration: 02:35:14 | English: AAC, 128 kb/s (2 ch) | 1.16 GB

Genre: Development / Programming

The traditional SQL database evolved from file systems. It assumes that all data can be expressed in scalar values in the columns of the rows of a table, just as file systems used fields in records of files. But the truth is that not all data fits into a traditional SQL model.
The storage models have changed. Columnar databases have no rows, but keep tables as columns which can be assembled into rows if needed. This means that query optimizations are very different. The MapReduce Model and Key-Value Stores do not have tables at all. Cloud storage is not like traditional, local file systems. Parallel processing and brute force replace clever indexing optimization.

Traditional SQL assumes that the data is static; think about common business applications like accounting and transaction processing. Changes to the data are explicit actions done by the database. Actions against the data are taken in other tiers of the application. But Streaming Databases (also known as Complex Event models) assume that data is constantly changing on its own. This would include sensor monitoring, stocks, commodity trades, and so forth. These events occur so fast that responses have to be built into the database.

Graph Databases do not have a table concept at all! They model pure relationships, expressed as a graph structure. SQL assumes that we know the relationships in the data. Graph databases discover the relationships. They are used for social network analysis, patterns in various kinds of flows. Think about a SQL query to find the minimal set of “the cool kids” in a social network whose adoption of a product makes it into the next trend.

Textbases or document databases have no concept of structured data. Instead of syntax, they get meaning from semantics. For example, Nexis, Lexis and Westlaw are used by researchers and lawyers to locate documents. Think about trying to write an SQL query to determine if a TV dinner meets the contractual obligation of a company to provide off-site employees with a meal equivalent to a fast-food order.

One of Dr. Codd’s 12 rules for RDBMS systems was that there must be a linear language to control and access the database. But Geographical Data (GIS) deal with maps, so they are 2 or 3 dimensional by nature. Their query languages are often graphic tools. For example, you can draw a polygon on a map and then ask how many people live inside it.

SQL is not always the right answer; it depends on the question!

An Overview of NoSQL Databases

Download uploaded
http://uploaded.net/file/nds06b4k/An.Ov.of.No.Da.part1.rar
http://uploaded.net/file/b01hpu9i/An.Ov.of.No.Da.part2.rar
http://uploaded.net/file/h20yum8g/An.Ov.of.No.Da.part3.rar
http://uploaded.net/file/8l7g3o55/An.Ov.of.No.Da.part4.rar
http://uploaded.net/file/jk2mzfop/An.Ov.of.No.Da.part5.rar

Download nitroflare
http://nitroflare.com/view/C87E6B668E91B7F/An.Ov.of.No.Da.part1.rar
http://nitroflare.com/view/DA6280885DE3D34/An.Ov.of.No.Da.part2.rar
http://nitroflare.com/view/3CE2C5FAAB0C026/An.Ov.of.No.Da.part3.rar
http://nitroflare.com/view/7CD0CFACD742777/An.Ov.of.No.Da.part4.rar
http://nitroflare.com/view/2F9C5A662707B6B/An.Ov.of.No.Da.part5.rar

Download 百度云

以下隐藏内容只提供VIP赞助会员

sorry! The following hidden content sponsorship VIP members only.

您必须 登录 才能发表评论!

网友最新评论 (1)

  1. NoSQL数据库入门教程 传统的SQL数据库是从文件系统演变过来的。其假设所有的数据可在表格的行与列构成所构成的单元格中以数值的形式显示,就如文件系统使用字段来记录文件一样。但事实是并非所有的数据都适合于传统的SQL模型。 存储模型已经改变了。列式数据库没有行,但是用表格形成的列可以被根据需要组合成行。这意味着查询优化也十分不同。MapReduce模式和键值存储根本就没有表格。云存储于传统也不一样。并行处理和暴力算法代替了智能索引优化。 传统的SQL假设数据是静态的;想象一下常见的企业应用程序,如会计和交易处理。对数据的改变无疑是通过数据库实现的。与数据有关的行为是在其他层实现的。但在复杂事件模型中,假设数据是一直变化的。这包括了传感器监控、股票、商品交易等。这些事件发生的速度之快以至于对其的响应需要建立在数据库中。 图形数据库根本就无需 表。他们的建模是纯关系型的,表现为图形结构。SQL假设我们了解数据中的关系。图形数据库发现这些关系。他们被用在社交网络分析、各种流的模式中。想象一下使用SQL在社交网络中查询谁是最棒的还是,这已经成为了接下来的趋势。 文本或文档数据库也无需结构化的数据。与语法不同,他们从语义中提取含义。例如,Nexis、Lexis以及Westlaw被研究院和律师用做寻找文档。想象一下,编写一个SQL查询来决定一个TV晚餐能否符合公司为其外出员工提供一样的快餐顺序。 Codd博士的12条RDBMS系统规则中的其中一条是必须有一个线性语言控制和访问数据库。但是GIS处理地图,这样2或3维就是自然而然的了。他们的查询语言常常是图像工具。例如,你可以在地图上绘制一个多边形,然后提问有多少人居住于其中。 SQL并非能够适用于所有情况,其取决于问题是什么。
    wilde(特殊组-翻译)3周前 (11-17)