rdbms concepts

The process of an RDBMSThe entire process of RDBMS processing user requests is as follows:650) this.width=650; "title=" Rdbms.png "src=" http://s3.51cto.com/wyfs02/M00/4F/E8/ Wkiom1rh9q7duc4eaaii8vr5skm680.jpg "alt=" Wkiom1rh9q7duc4eaaii8vr5skm680.jpg "/>1, when the user requests data query and other operations, the first to establish a connection with the database server. Therefore, the Connection Manager is preferred and the connection is establishe

, (such as by the backend job generation, can be implemented by the application of double write) No need for transaction transaction support; There may be very high qps/tps (for example, 10k+ query/transaction per second); There are very high response speed requirements ( Typical scenario:各类计数器；各类cache层（商品列表页，各类配置信息，商品描述信息等）；Analytics Platform:Hadoop：ETL；科学分析；GP：BI分析；各类报表；Hbase：在线系统；OLAP分析；DocDB：应用相对简单，数据结构相对复杂，支持快速开发，非事务类处理的信息处理系统。如知识问答、社区等；3. Performance OptimizationWhen an ex

The difference between hbase and traditional relational databasesHBase is suitable for databases with unstructured data stores. A data storage method between the map Entry and the DB row.1. Data type: HBase only the simple string type, it only saves the string all types are handed to the user to handle. Relational databases can select types2. Data manipulation: HBase operation only very simple insert, query and other operations, the table is separated from the table, there is no join3. Storage m

How BI projects are developed:Learn how OLAP is analyzed:Multidimensional modeling analysis of data, that is, the design of their own data, then the program automatically generate the data of the square bodyData side body:1. Automatic table structure, only the columns you need2. Generate an SQL statement (with query criteria)3. Cache sql, through your pre-defined multidimensional analysis, establish the relationship between the fact table and the dimension table, generate SQL is the cache SQL, a

box, import the table structure by reverse engineering. The imported data types and field names need to be adjusted. Add fields directly here.III. mapping 3.1 Creating project design EngineeringOdi->designer->projects->new project, define a name for the project, save it.3.2 Importing Knowledge modulesRight-click the project name below the knowledge Modules, select Import Knowledge Modules, where the module/u01/oracle/middleware/oracle_home/odi/sdk/ Xml-reference path, select all the modules her

Transferred from: a q's home 1. Basic concepts of osworkflowIn the commercial and open-source world, osworkflow is different from these existing workflow systems. The biggest difference is that osworkflow has excellent flexibility. It may be difficult to get started with osworkflow (some people say it is not suitable for beginners of workflow). For example, osworkflow does not require graphical tools to develop workflows, but it is recommended to manu

Principles of database systems (I)-basic concepts of database systems and concepts of Database Systems Concept Model: (1) express the overall logical structure of the data, which is a comprehensive description of the data involved in the entire application project by the System user. (Overall) (2) modeling data from the perspective of user needs. (Viewpoint) (3) independent from hardware and software. (In

PLSQL_Oracle Temporary Table basic concepts and usage (concepts), plsql create Temporary Table 2014-06-08 BaoXinjian I. Basic Concepts 1. My Understanding of temporary tables: Create a table in Oracle. This table is not used for other functions. It is mainly used for some special functions of your software system. When you use it, the data in the table is useles

Basic concepts of JMS Learning (I) and basic concepts of jms Learning I interviewed one or two companies over the past two days. Due to the use of JMS in the most recent project in my resume, the interviewer seems to be very interested in this, so I was asked, but unfortunately, in addition to using JMS, I had a poor answer to some of their questions about JMS. The direct result was an interview failure. At

1. concepts related to ASM (concept taken from: the world of amasha) 1. What is ASM (Auto Storage Management) 1 Automatic Storage Management is a tool used to manage disks.2 Supports striping, mirror data files, and restore files between multiple physical devices.3 Files are evenly distributed across all disks in the disk group according to the allocation unit aus (Allocation units). ASM uses the index technology to track the location of each aus.

[Basic concepts of exceptions] _ notes on basic concepts of exceptions Understand basic concepts of exceptionsMaster basic Exception Handling formatsUnderstanding the inheritance structure of exception classesMaster Java Exception Handling Mechanism Exception:An exception is a type of command flow that causes program interruption. If the exception is not correctl

ArticleDirectory Applications Game Logic Operations operations Events event Connections and timeouts connection and timeout Basic concepts the following article will show you the important basic concepts for photon. The following are important basic concepts of photon (applications ). Program An application is the server side log

Objective-C basic notes (1) Basic concepts and first procedures, concepts first featuresI. Basic Concepts Objective-C (OC) is the core language for iOS development. Apple maintains and works with C and C ++ during the development process. OC is mainly responsible for the UI interface, C language and C ++ can be used for graphic processing. C language is a process

Four core concepts of CSS and four core concepts of CSSCascading Style Sheet (CSS) is a set of format setting rules used for webpage Style design. By setting the page format with CSS Styles, you can separate the content and representation of the page. The page content is stored in the HTML document, while the CSS rules used to define the representation are stored in another file or a part of the HTML docume

Basic concepts and architecture of Docker, basic concepts and architecture of docker Introduction to Docker container Technology Docker containers depend on two important features of the Linux kernel. Namespaces namespace Control group Understanding these two features can help us better understand the resource allocation and management of Docker containers. 1. Namespaces namespace Many programming languages

Basic concepts of JavaScript and basic concepts of javascript I. Case Sensitive All variables, function names, and operators in ECMAScript are case sensitive. For example, the variables test and Test indicate two different variables respectively, Ii. identifier The identifier refers to the name of a variable, function, attribute, or function parameter. One or more characters of the identifier in combin

Summary of WebService Learning Concepts and summary of webservice concepts Concept Summary: WebSerevice is a remote call technology across programming languages and operating systems.Transmission Protocol:HTTPTechnical composition:XML + XSD, SOAP, WSDLXMLEncapsulate the data format to solve the problem of data representationXSDDefine a set of data type standardsSOAPProtocol = HTTP protocol + XML data forma

that the minor is under 18 years of age. In Chinese moral concepts, the 13-year-old man began to marry his wife and have children. Li Tianyi was a minor in law, but in people's hearts, he was an adult, we should bear the corresponding responsibilities. If the news reports "10-year-old Li Tianyi, rape a woman", everyone will think, isn't it better? Therefore, this shows the conflict between Chinese traditional cultural

OC-Concepts and usage of protocols, oc-concepts of protocols In the previous article, we introduced the class extension in OC: Extend. The protocol in OC is equivalent to the interface (abstract class) in Java, but the name in OC is more vivid, because when we are learning interfaces in Java, it can be seen that the interface is equivalent to a contract (Protocol), marking its implementation class. Of cour

JavaIO stream (1): basic concepts and basic concepts of javaio stream I. input and output streams Input stream: when the program is running, you may need to read the required data from external storage media or other programs and use the input stream. Output stream: After a program processes data, it may write the processing result to a permanent storage media or send it to another program, using the output