what is data deduplication

#region DataTable to Heavy/// The above is the C # DataTable data deduplication content, more relevant content please pay attention to topic.alibabacloud.com (www.php.cn)! 

Array deduplication is difficult to calculate. there is an array that needs to be deduplicated. the format of the array is discussed online. Reply to discussion (solution) Paste the sample array output by var_export. the basis for not discussing is not discussed. In fac

Tags: mongodbRecently wrote a crawler tool, the data stored in the Web site MongoDB, because the data are duplicated, so I set up the database when the index, the following is my step, the set name is Drugitem,Here is the collection:I want to create a unique index for the na

); - //registering a merge class $Job.setcombinerclass (Reduce.class); the //Register Reducer Class theJob.setreducerclass (Reduce.class); the //registering the output format class theJob.setoutputkeyclass (Text.class); -Job.setoutputvalueclass (Text.class); in //setting the input and output path theFileinputformat.addinputpath (Job,NewPath (otherargs[0])); theFileoutputformat.setoutputpath (Job,NewPath (otherargs[1])); About the //Run the

)This is the magic of data structures.So what is an algorithm? This can only be forced to continue the analogy. I want to learn Kung fu. After I entered the book Room of martial Arts cheats, I ran out with a lot of books. Open a look, there is a dragon 18 palm, nine Yin Cano

Label:How is duplicate data removed from the Oracle database? When working with data tables, there are often duplicate data, so how do you delete them? Let's talk about removing data duplication from Oracle databases. There are two ways we are going to talk today.First, acco

A sentence to understand what is called data structure and algorithm, try to let people who do not understand the program can understand This issue has been closed due to non-development-related issues directly Reply content: A sentence to understand what is called

Business Requirements:A table has the Id,n1,n2,n3 field, which is a new empty table,Table B has id,n1,n2,n3,n4,n5 fields, such as old tables containing data,Now the record of the N1,N2,N3 combination in B table is re-imported into a table, and a table primary key is also entered valueScenario: The records of B table af

When an insert statement is used, what data needs to be enclosed by quotation marks and what data does not need to be enclosed by quotation marks?Create Database mydbUse mydbCreate Table customer_data(Customer_id smallint,First_name char (20 ),Last_name char (20 ),Phone char

main field = @idFetch cur_rows into @id, @maxEndClose Cur_rowsSET ROWCOUNT 0Method TwoThere are two meanings of duplicate records, one is a completely duplicate record, that is, all fields are duplicated records, and second, some key fieldsDuplicate records, such as the Name field, and the other fields may not be repeated or repeated can be ignored.1, for the first kind of repetition, easier to solve, usin

Label:In a database table, duplicate values may be included. That's not a problem, but sometimes you might want to just list different values (distinct). Keyword DISTINCT is used to return only different values. Table A: 1. Acting on a single rowSelect distinct from A The following results are performed: Acting on multi-column Example 2.1Select distinct from A The following results are performed: In fact, it is