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, they can even build computers with arm and DSP chips! However, no software can run. You can only run the software you are writing! The mobile phone is like this ~! The topic is far away ....Now, C # is based on.. NET platform ,. net is based on the Windows operating system, and the Windows operating system is based on 32-bit assembly instructions. The Assembly is based on the machine language, and the machine language is based on the machine manufacturer. Ultimately, it depends on industry sta

In fact, there are still few Blog content updates, that is, a blog will always have new replies, but after a new restoration, it will often sink on the home page, and others will often read the blog at that time, A few days later, I often don't pay attention to it. So whether or not we can refresh a blog with a new reply. Of course, it is best to let software users know that this blog has been updated with a new reply or content. I may still use m

Java RSS, ArticleThe most common error is . Text-ApplicationProgramError!DetailsFormatexceptionThe datetime indicated by the string is out of the range. It's really amazing! My blog cannot be accessed multiple times, and the server seems to be prone to errors! The common error is "Service unavailable ".I almost changed my blog. After searching for a long time, I applied for blogchina. It didn't support operabrowser. I rely on it! Note: The error cause is found!The URL of the article

Lost update: Two transactions update a row of data at the same time, the last transaction update will overwrite the first transaction update, resulting in the first transaction update data loss, which is caused by no lock; 1. Dirty reads: Dirty reading means that when a transaction is accessing the data and the data has been modified, and the modification has not been submitted to the database, another transaction accesses the data and then uses the data.e.g.The original salary for 1.Mary was 1

Http://blog.163.comAssume that the user name is abcd.So the blog address is http://blog.163.com/abcdAccording to this ruleAnd know Netease blog login page for http://blog.163.com/login.htmlBecause Netease blog can apply for a user name with (.), I

Preface Many of my friends asked me what software I wrote for my blog. I hope my blog page is quite interesting !!! I am very impressed. Here we will share our methods.Customized Style My blog has made some changes to the H1 style, added a

MySQL InnoDB Transaction isolation level dirty read, Repeatable read, phantom read MySQL InnoDB transactions are isolated at four levels. The default value is repeatable read ). · READUNCOMMITTED ). Another transaction modifies the data but has not yet committed it, And the SELECT statement in this transaction reads th

Database transaction isolation level-dirty read, phantom read, non-repeated read, transaction level I. database transaction isolation level There are four database transaction isolation levels, from low to high: Read uncommitted, Read committed, Repeatable

Database transaction isolation level and dirty read, phantom read, non-repeated read, transaction level I. database transaction isolation level There are four database transaction isolation levels, from low to high: Read uncommitted, Read committed, Repeatable

I. Database transaction ISOLATION LEVEL There are 4 isolation levels for database transactions, from low to high to read uncommitted, Read committed, Repeatable read, and Serializable, which can solve the problems of dirty reading, non-repeatable reading, and Phantom reading one by one. √: May appear x: does not appear Dirty

1. Some problematic reads in the transaction: dirty read, non-repeatable read, Phantom readThe dirty read (Dirty Read) transaction T1 updated the contents of a row of records, but did not commit the changes. The transaction T2 reads the updated row, and then T1 performs the rollback operation, canceling the modificatio

Ext: http://blog.csdn.net/fatherican/article/details/44966921 1, Dirty Read One transaction reads another transaction, and the pending modification is dirty read. Here's the so-called modification, in addition to the update operation, do not forget, but also includeInsert and delete operations. Consequences of dirty reading: If the latter transaction is rolled back, all changes made to it will be revoked.

4 attributes of a database transaction:Atomicity (atomic): both succeed or fail;Consistency (consistency): After a transaction operation, the database is in the same state as the business rules; for example, after the A,b account transfers, the total amount remains unchanged;Isolation (Isolation): transactions in operations do not affect each other;Persistence (Durability): After a transaction is committed, it is persisted to the database. Dirty read,

Issues arising from transaction concurrency:Dirty reads: One transaction reads data that is not committed by another transactionTransaction 1: Updating a single piece of dataTransaction 2: Read record of transaction 1 updateTransaction 1: Commit commits are calledAt this point, the data read by transaction 2 is data stored in database memory, called dirty reads.The data

1. Dirty read : Dirty read refers to when a transaction is accessing the data, and the data has been modified, and this modification has not been committed to the database, then another transaction also accesses the data, and then used this data. 2. Non-repeatable reads : Refers to the same data that is read multiple times within a transaction. When this transact

　　Main content:1. Initial file operation2. Read-only (R,RB)3. Write only (W,WB)4. Append (A, AB)5. Read and write (r+)6. Write-read (w+)7. Additional write read (A +)8. Other methods of operation9. File modification and another way to open a file handleA. Operation of the initial fileusing Python to

Original: http://www.cnblogs.com/phoebus0501/archive/2011/02/28/1966709.html Dirty reading is that the data has not been submitted (not necessarily a successful commit), it was used by other affairs.1. Dirty Read : Dirty read refers to when a transaction is accessing the data, and the data has been modified, and this modification has not been committed to the database, then another transaction also accesses

I. DATABASE TRANSACTION ISOLATION LEVELThere are 4 isolation levels for database transactions, from low to high, READ UNCOMMITTED,Read Committed,Repeatable read, andSerializable, which can be resolved individually by each of the four levels Problems such as dirty reading, non-repetition reading, and Phantom reading. √: May appear x: does not appear

Dirty read (dirty read) unrepeatable read (phantom problem) Parsing1. Dirty read First, distinguish between dirty pages and dirty data Dirty pages are modified pages in the memory buffer pool. They are not flushed to the hard disk in time, but are already written to the redo log. It is normal to

Label:form of SQL Server data store Pre-read: Use the estimated information to go to the hard disk to read the data to the cache. Pre-read 100 times, which is estimated to read 100 pages of data from the hard disk to the cache. Physical reads: After the query plan is generated, if the cache is missing the