Sql Server Make Column Unique

The complete collection of SQL statement operations deserves to be permanently stored the following statements are part of the MSSQL statement and are not available in Access. SQL classification: ddl-data Definition language (create,alter,drop,declare) dml-Data Manipulation Language (Select,delete,update,insert) dcl-Data Control Language (Grant,revoke, Commit,rollback first, briefly introduce the basic statement: 1, Description: Create number ...

At present, big data has become a hot topic in the world. Gartner ranked large data as the most important technical direction for CIOs in the 2012, and IDC believes that big data is one of the most significant aspects of the enterprise's capacity reserve. In the recently held Teradata Data Warehouse and Enterprise Analysis Summit, the industry's hot talk "Data gold", looking forward to the bright future of the big data age. China Cloud reporter was fortunate to interview the Teradata company Chief Technical Officer Baoliming (Stephen BROBST), Teradata How to ...

SQL used to manipulate the database is generally divided into two kinds, one is the query, which is what we call the SELECT statement, the other is to update the statement, also known as data manipulation statements. The implication is to modify the data. There are 3 statements in the standard SQL, which are INSERT, UPDATE, and DELETE. There is another REPLACE statement in MySQL, so this article uses MySQL as a background to discuss how to make updates in SQL. First, INSERT and REPLACE I ...

The concept of large data, for domestic enterprises may be slightly unfamiliar, the mainland is currently engaged in this area of small enterprises. But in foreign countries, big data is seen by technology companies as another big business opportunity after cloud computing, with a large number of well-known companies, including Microsoft, Google, Amazon and Microsoft, that have nuggets in the market. In addition, many start-ups are also starting to join the big-data gold rush, an area that has become a real Red sea. In this paper, the author of the world today in the large data field of the most powerful enterprises, some of them are computers or the Internet field of the Giants, there are ...

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In large data technology, Apache Hadoop and MapReduce are the most user-focused. But it's not easy to manage a Hadoop Distributed file system, or to write MapReduce tasks in Java. 　　 　　Then Apache hive may help you solve the problem. The Hive Data Warehouse tool is also a project of the Apache Foundation, one of the key components of the Hadoop ecosystem, which provides contextual query statements, i.e. hive queries ...

A news incident last week attracted media attention, with nearly 450,000 passwords from 450,000 yahoo services called ' Yahoo Voice ' hacked. The comment on the incident said that hackers mainly through SQL injection (SQL injection) technology is the hacker from the database to obtain information and then release the information of the main technology adopted. Even if the original article is modified, you can find the error if you do a check. Technology is the same, as every more in-depth discussion can find new problems. ...

Big data and Hadoop are moving in a step-by-step way to bring changes to the enterprise's data management architecture. This is a gold rush, featuring franchisees, enterprise-class software vendors and cloud service vendors, each of whom wants to build a new empire on the Virgin land. Although the Open-source Apache Hadoop project itself already contains a variety of core modules-such as Hadoop Common, Hadoop Distributed File Systems (HDFS), Hadoop yarn, and Hadoop mapreduce--...

The recent investment in cloud computing by major giants has been very active, ranging from cloud platform management, massive data analysis, to a variety of emerging consumer-facing cloud platforms and cloud services. And the large-scale data processing (Bigdata 處理) technology which is represented by Hadoop makes "Business king" Change to "data is king". The prosperity of the Hadoop community is obvious. 　　More and more domestic and foreign companies are involved in the development of the Hadoop community or directly open the software that is used online. The same year with ...