Float Data Type

Either in the pitiful free database space or large e-commerce sites, reasonable design table structure, make full use of space is very necessary. This requires that we have a full understanding of the commonly used MySQL data types for database systems. Now I will write down my little experience to share with you. The numeric type of the MySQL data type The numeric type is divided into three categories according to my classification: integer classes, decimal classes, and numeric classes. My so-called "digital class" refers to DECIMAL and NUMERIC, which are the same type. It is strictly speaking not ...

1. Boxing, unpacking or aliases many of the introduction of C #. NET learning experience books on the introduction of the int-> Int32 is a boxing process, the reverse is the process of unpacking. This is true of many other variable types, such as short <-> int16,long <->int64. For the average programmer, it is not necessary to understand this process, because these boxes and unboxing actions can be automatically completed, do not need to write code to intervene. But we need to remember that ...

This article is my second time reading Hadoop 0.20.2 notes, encountered many problems in the reading process, and ultimately through a variety of ways to solve most of the. 　　Hadoop the whole system is well designed, the source code is worth learning distributed students read, will be all notes one by one post, hope to facilitate reading Hadoop source code, less detours. 1 serialization core Technology The objectwritable in 0.20.2 version Hadoop supports the following types of data format serialization: Data type examples say ...

UPC language http://www.aliyun.com/zixun/aggregation/18736.html > Allows users to control how data is laid out, and the layout of the data affects the performance of the program. This paper, through a series of program examples, makes the UPC language learners understand clearly how to layout the data reasonably from the angle of performance optimization. The data distribution private data in the UPC is distributed in the UPC, and private data can only be accessed by the thread on which it resides. When ...

Today, I will share all the questions I encountered during the interview and share how to answer them. Some of these questions are relatively normal and have a certain theoretical background, but some are very innovative.

The disadvantage of using HDFS to save a large number of small files with use using the: 1.Hadoop Namenode saves "meta information" data for all files in memory. According to statistics, each file needs to consume NameNode600 bytes of memory. If you need to save a large number of small files will cause great pressure on the namenode. 2. If the use of Hadoop MapReduce small file processing, then the number of Mapper will be the number of small files into a linear correlation (Note: Filei ...

Overview 1, what is C #? C # is a programming language designed by Microsoft. 　　It is loosely based on C + +, and there are many aspects similar to Java. Microsoft describes C # in this way: "C # is a simple, modern, object-oriented, and type-safe programming language derived from C and C + +." C # (read ' Csharp ') has been ported mainly from a family of + + + + programming languages, and the programmers of both C. and C + + are immediately familiar with it. C # attempts to combine Visual Basic's ...

*st (000036.SZ) is only the first case in which the Social Security Fund successfully copied four quarters last year.　　2008, the National Social Security Fund equity investment yield of 6.75%, the establishment of 8 years of equity investment for the first time, so that the Social Security Fund and its trustee's investment ability is questioned. However, since the four quarter of last year, the Social Security Fund has increased significantly in two consecutive quarters, allowing it to benefit from the rebound this year.　　Social security for this market grasp ability not only earlier than the public fund, or even more than experienced qfii. Data show that the National Social Security Fund 2008 New ...

Offering a service to get calculated discounts by reserving instances, Amazon's goal is clear: to better capacity planning by identifying the cloud infrastructure used by the user segment, while also giving users direct benefits. So far, the industry has a certain understanding of the reservation, including the type (Heavy, Medium, Light) and the terms (1 or 3 years), but here's 6 reservation examples related matters you may not understand. 1. The double benefit Reservation example brings a double benefit to the user: first, the ability to compute the discount; second, the capacity of the ...

In the mobile phone product design process, due to the limited carrying capacity of the mobile phone interface, product features continue to expand, you must open the application after the user to inform him some of the novel features, and guide him to complete some of the major task processes, so that users do not Lost in unfamiliar applications overwhelmed. Help users quickly master the use of applications, to experience the fun of the application, novice guide has become a must-design link. The direct goal of user guidance is to help users better use of the product, the ultimate goal is to enhance customer satisfaction. Although, most of the time, we can through reasonable design, as much as possible ...