If Condition In Oracle Query

"IT168 Technical Documentation" Since Oracle and HP launched Exadata, I have been very concerned about this product, and previously wrote an Oracle database machine introduced it. 　　Last year, Oracle and Sun merged to launch Oracle Exadata V2, which has several changes compared to previous generations: first, using sun hardware; second, it claims to support OLTP applications; third, Oracle 11g R2 offers more new features. Exadata S ...

The greatest fascination with large data is the new business value that comes from technical analysis and excavation. SQL on Hadoop is a critical direction. CSDN Cloud specifically invited Liang to write this article, to the 7 of the latest technology to do in-depth elaboration. The article is longer, but I believe there must be a harvest. December 5, 2013-6th, "application-driven architecture and technology" as the theme of the seventh session of China Large Data technology conference (DA data Marvell Conference 2013,BDTC 2013) before the meeting, ...

We want to do not only write SQL, but also to do a good performance of the SQL, the following for the author to learn, extract, and summarized part of the information to share with you! (1) Select the most efficient table name order (valid only in the Rule-based optimizer): The ORACLE parser processes the table names in the FROM clause in Right-to-left order, and the last table in the FROM clause (the underlying table driving tables) is processed first, In the case where multiple tables are included in the FROM clause, you must select the table with the least number of records as the underlying table. If...

Absrtact: With the rapid take-off of China's economy, the development of environmental pollution problems intensified, haze in all regions raging, PM2.5 index frequent "explosion", the daily life of the people caused great trouble, aroused public opinion's strong concern. The Government attaches great importance to and put PM2.5 monitoring work in the focus of environmental protection work. Cloud creates storage independent innovation PM2.5 cloud monitoring platform breaks the traditional research and development way, utilizes the innovative design idea, causes the environmental protection and the cloud computing high-end technology organic combination, the structure massive monitoring data storage, the processing platform, may reflect each region's air quality microcosmic, for the public ...

As we all know, Java in the processing of data is relatively large, loading into memory will inevitably lead to memory overflow, while in some http://www.aliyun.com/zixun/aggregation/14345.html "> 　　Data processing we have to deal with massive data, in doing data processing, our common means is decomposition, compression, parallel, temporary files and other methods; For example, we want to export data from a database, no matter what the database, to a file, usually Excel or ...

When it comes to big data, it has to do with Alibaba. The world's leading E-commerce enterprise, the amount of data processed every day is unmatched by any other company, it is also transforming into a real data company--mysql is an important weapon in the transformation of Alibaba. 　　A database architect who interviewed Ali, who believes Ali has the best performance of open source MySQL, beyond any relational database and NoSQL. In the 2009, Oracle acquired the copyright of MySQL by acquiring Sun, and the industry began to question the use of Oracle ...

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The scalability of the system is the main reason for promoting the development of NoSQL movement, including distributed system coordination, failover, resource management and many other features. That makes NoSQL sound like a big basket that can be stuffed with anything. Although the NoSQL movement does not bring fundamental technological changes to distributed data processing, it still leads to extensive research and practice on protocols and algorithms. It is through these attempts to gradually summarize some effective database construction methods. In this article, I will focus on the NoSQL database distributed special ...

The scalability of the system is the main reason for promoting the development of NoSQL movement, including distributed system coordination, failover, resource management and many other features. That makes NoSQL sound like a big basket that can be stuffed with anything. Although the NoSQL movement does not bring fundamental technological changes to distributed data processing, it still leads to extensive research and practice on protocols and algorithms. It is through these attempts to gradually summarize some effective database construction methods. In this article, I will focus on the distributed features of the NoSQL database ...

In 2017, the double eleven refreshed the record again. The transaction created a peak of 325,000 pens/second and a peak payment of 256,000 pens/second. Such transactions and payment records will form a real-time order feed data stream, which will be imported into the active service system of the data operation platform.