sql for data analysis udacity

Technical preparationBased on SQL Server2008R2, Microsoft uses a simpler case Library (Northwind) for parsing.IntroductionThe so-called index application is in our daily write T-SQL statement, how to use the existing index, then analysis is what we write query conditions, in fact, most of the situations are nothing more than the following:1. Equal to the predicat

this regard. The most classic is the enterprise-level development package that Microsoft strongly recommends: duwamish. For those who want to learn about the Dal design under. net, this is a good start. For a complete analysis, you can refer to "csdn development expert, 2003.11". This article does not Let's go into details. The duwamish solution was used in a project that the author was involved in. Phase, I feel that this is a good referen

plan.SQL Server 2008 also provides a compatibility view of Sys.syscacheobject, which holds all the information about the execution plan.　　Clear CacheSometimes you need to clear the cache for the next analysis when performing profiling. SQL Server provides a number of tools to clear cached performance data. Use the following statement to accomplish these tasks.Cl

Today to review the basic knowledge of data storage, unity3d commonly used in the storage of data with unity Playerprefs, XML documents, JSON documents, and commonly used lightweight database SQL, involving a lot of trivial knowledge, here to summarize their own, It is convenient to know the new in the future.Playerprefs Storing dataPlayerprefs storage is very si

Sys.syscacheobject, which holds all the information about the execution plan.　　Clear CacheSometimes you need to clear the cache for the next analysis when performing profiling. SQL Server provides a number of tools to clear cached performance data. Use the following statement to accomplish these tasks.Clear the global cache using the following statement:DBCC dro

Original: SQL Server 2008 Spatial Data Application series five: Using spatial data types in data tablestips, the prerequisites for reading this blog post are as follows:1. This sample is based on Microsoft SQL Server R2 Commissioning.2. Experience in Transact-

, delete, and change operations increases a certain amount of work, so it will help to optimize those poorly performing SQL Server applications by increasing the appropriate indexes and removing suboptimal indexes from places where appropriate. The practice shows that the reasonable index design is based on the analysis and prediction of various queries, and only when the index is correctly combined with th

--->> advancedBy the Red Trap on the 2 selected, remove the SQL statement SET Statistics IO/TIME on/off trial effect. Oh, you did it.3. Review the execution plan and the execution planSelect the query statement, click and then look at the message, the following legend appearsFirst of all, the statement of my example is too simple, your whole complex, forgive Ah.Analysis : The mouse on the icon will show the details of this step execution, each table b

did it.3. Review the execution plan and the execution planSelect the query statement, click and then look at the message, the following legend appearsFirst of all, the statement of my example is too simple, your whole complex, forgive Ah.Analysis : The mouse on the icon will show the details of this step execution, each table below shows a cost percentage, the number of analysis station is a block, can be based on the redesign of the

Data Structure and algorithm analysis-index, data structure and algorithm Index Author: xiabodan Source: http://blog.csdn.net/xiabodan ComputingMethods and data structures are the core content of computer science. As a programmer, programming is our practical project. However, writing programs is not enough. It takes

Tags: Step data scientist Architecture agreement New Hope story led meaning avoidanceWhy SQL is beating NoSQL, what this means for future data: http://geek.csdn.net/news/detail/238939 The translator notes: After years of silence, today's SQL is coming back. What's the reason? What impact does this have on the

, 'E '); Insert into t1 values (3,3, 2,2, 'C '); Insert into t1 values (7, 4, 5, 'G '); Insert into t1 values (6, 6, 4, 4, 'F '); The storage structure of table t1 is shown in (only the idx_t1_bcd index and table t1 structure are drawn, and the primary key index of table t1 is not included ): For a brief analysis, the idx_t1_bcd index has three fields: [B, c, d] (Note: if it is an InnoDB-type clustered index table, idx_t1_bcd will also contai

Tags: OLAP online analytics for Data warehouse applicationsRelated articles:Data Warehouse Application (i): Data Warehouse model designData Warehouse Application (ii): Data extraction, transformation, loading (ETL)前言：有关数据仓库的研究，并不仅仅停留在理论上。目前，几种主要的RDBMS产品，如Oracle、SQL Server、Informix和 Sybase等，都可以为用户提供数据仓库项目的开发工具；而一些通用的应用程

This article mainly introduces how to prevent SQL injection analysis in PHP, which is of great practical value. For more information about how to prevent SQL injection in PHP, see the example in this article. Share it with you for your reference. The specific analysis is as follows: I. problem description: If the

This article mainly introduces how to prevent SQL injection analysis in PHP, which is of great practical value. For more information about how to prevent SQL injection in PHP, see the example in this article. Share it with you for your reference. The specific analysis is as follows: I. problem description: If the

execution plans. 　　 Clear Cache During performance analysis, you sometimes need to clear the cache for the next analysis. SQL Server provides some tools to clear cache performance data. Use the following statement to complete these tasks. Use the following statement to clear the global cache: DBCC dropcleanbuffers; C

predictable, the algorithm generates a separate decision tree for each predictable column.The principle of the algorithm:The Microsoft decision tree algorithm generates a data mining model by creating a series of splits in the tree. These splits are represented as "nodes". Whenever an input column is found to be closely related to a predictable column, the algorithm adds a node to the model. The algorithm determines how the split is divided, primaril

also be selected. ETL tools and OLAP tools are essential, such as Informatic, eassbase. In the actual data analysis project, it takes six hours to process 60 million log data entries per day to use SQL Server 2000, and three hours to use SQL Server 2005. 2. Writing excellen

I spring and autumn writer: YANZM0x00 backgroundThis week, get a source material is 08cms, this source code in the official website does not open source download, need to buy, by a teacher to provide, audit time found this CMS data transfer more complex, use static analysis of the way bad operation, just this week small three upper (new computer), On the direct installation of Phpstorm+xdebug+xdebug-ext (Fi

Tags: action base row It lock represents time res this hold MYSQOriginal text: A brief analysis of the locking problem of SQL Server to prevent the range lock of Phantom read under Serializable isolation level The source of this article: http://www.cnblogs.com/wy123/p/7501261.html(It is not the original works right to retain the source, I my book still far to reach, just to link to the original text, becaus