what is cmmi and explain levels

1) Transaction (Transaction): is the smallest unit of work for a database operation, a series of operations performed as a single logical unit of work, which are submitted to the system as a whole, either executed or not executed; a transaction is a set of operations that cannot be re-partitioned (the Working Logic unit); 2) A transaction has 4 properties, often called an acid attribute: 3) atomicity (ato

Physical layer: The lowest level of abstraction that describes how data is actually stored. The physical layer describes the complex underlying data structures in detail and is what the database vendors that develop the DBMS should study. Logical layer: An abstraction that is slightly higher than the physical level, d

= 1 ; While @ I 1000 Begin Insert Into Student Values ( @ I , ' Zhangsan ' + Cast ( @ I As Char )) Set @ I = @ I + 1 ; End ; Go Because the ID column is set as the primary key, SQL Server automatically adds a clustered index to it. If we use the following statement to update table data, Begin Tran UpdateStudentSetName='Zhangsan' WhereID=1000; Then query the current lock status and execute the following t

Baidu Antivirus real-time monitoring the difference between the different levels are as follows: Baidu Antivirus when the choice of monitoring level for "high": Baidu Antivirus will perform the most stringent protection, to ensure safety. Baidu Antivirus when the choice of monitoring level is "medium": Baidu Antivirus will ensure that the system performance and security to achieve the best balance. Baidu

used in the third party Python library; 3, understand at least one SQL database (mysql/sqlserver/oracle); 4, love programming, with outstanding code style; 5, the director has a rational, with outstanding self-learning ability, analysis and problem-solving skills. Job Definition: Python data analysis So, let's take a look at the basic requirements of these three posts and what are the similarities and differences. First level: Python's fundamental sy

Overview About PEAR,PECL These two things, beginner PHP when you know, but it seems to use people rarely add to the previous is also in Windows to do development, so do not know much, now turn to the Mac, the two things thoroughly to find out. What is Pear Pear's full name is PHP Extension and application Repository

information (typically a user name and password). After these credential information is validated, the system generates an authentication ticket (ticket) and returns it to the client. An authentication ticket maintains the user's identity information during a user's session, and optionally, a list of roles to which the user belongs. l None. This authentication mode is used to indicate that you do not wan

What I saw on a website is well written and shared with you! I want to explain to my new employee what is work! At that time, the company recruited a large number of new students who graduated from undergraduate and postgraduate courses. The average age

/** 2, please explain the meaning of the characters ' \ ' in Java, what is the role?*Answer* In Java the backslash ' \ ' represents the meaning of the escape character, which is a marker** When the compiler reads this tag, it knows that the next character is not an ordinary

to create field exits.An example of a user exits:-MODULE user_exit_0001 INPUTCase Okcode.When the ' Back OR EXIT '.Case Sy-dynnr.When ' 100 '.SET screen 0.LEAVE screen.When ' 200 '.******************************************************************************Note that the can write any code that satisfy your needs. ****It is wrote as a sample code for reference sake. ****And you can test it. ***********************************************************

A method is named and attached to an object. So, for example, the A method is like a function and is contained inside a class. Its scope is limited to that class, and cannot affect variables outside the that class, even global variables. If you need to affect a variable outside of a class, the just use a function (or r

Explain syntax EXPLAIN SELECT ... Variant: 1. EXPLAIN EXTENDED SELECT ... "Decompile" The execution plan into a SELECT statement, run show warnings to get the query statement optimized by the MySQL optimizer 2. EXPLAIN Partitions SELECT ... Explain for partitioned tabl

?>Output Result:Value:oneValue:twoThe first foreach with does not change the contents of the array:Instead of the last loop, $value references the last item in the array (you can test that the result of the second loop will not change after the first loop is unset ($value).In your second foreach is also used by the $value variable, which creates a weird problem (you can change a variable, such as $val, the

To achieve file sharing, the file system must provide file protection, which provides measures to protect file security. The protection of the file system is mainly to prevent unauthorized users from destroying and attacking the file.The protection of files can be achieved through user-oriented access control and data-oriented access control.For example, the user is required to enter the user name and user

to use CSS3 in your site, make sure you have a compatible method for browsers that don't support CSS3. browser support status for CSS3: Firefox (3.05 ... Partial support) Google Chrome (1.0.154 ... Partial support) Google Chrome (2.0.156 ... Better support) Internet Explorer (IE7, IE8 not supported) Opera (9.6 ... Rarely supported) Safari (3.2.1 Windows ... Better support)What is CSS

expense of more than packet filtering firewall security performance, in the network throughput is not very large case, perhaps the user will not be aware of what, however, when the data exchange frequently, agent firewall has become the bottleneck of the entire network, And once a firewall's hardware configuration fails to withstand high levels of data traffic,

Explain to relatives and friends what the series is IP, port, and domain name IP addresses, ports, and domain names are no stranger to professional people, but they may not be familiar to non-professional people. The purpose of this article is: First, I want to install "brick house" (in fact I don't know much about it

return value is also sent back to the application on Server A, also to be serialized, Server A received, then deserialized, revert to in-memory expression, to a server on the application Why RPC? is a requirement that cannot be done within a process, or even within a computer, by local invocation, such as communication between different systems, or even between different organizations. Because computi

What is the difference between get and post in PHP and when to use a post to explain difference: 1, get is generally the data transmitted after the hyperlink, the amount of data transmitted is small, can not be greater than 2KB. 2, post

the startup priority. Not only can the servlet generate HTML script output, but it can also generate a binary tab output.· The servlet is widely used, and many popular frameworks are now supported by Servlets, such as when the Shh,spring container is started, to load spring containers and Actioncontext in Web,xml to initialize some of the spring's parameters. such as dependency injection, database table ma