higher precedence

LUA supports commonly used logical operators and, or, and not. Nil is seen as false in a logical operation, except that the Boolean false and the value outside of nil are considered true. If the first operand is the result of the False,and operation

1. Lock mechanism1) When dealing with concurrent reads and writes, a set of locking systems is usually used to solve the problem. The lock system consists of a read lock (also known as a shared lock) and a write lock (also known as an exclusive lock)

Transferred from: http://www.cnblogs.com/mark-chan/p/5384139.htmlIntroduction to Stored ProceduresSQL statements need to be compiled and executed, and stored procedures (Stored Procedure) are a set of SQL statements that are compiled in order to

The biggest advantage of AlwaysOn relative to database mirroring is the readable copy, which adds a new feature to the read-only route, which is to configure read-only routing to achieve read-write separation; Of course, the read-write separation

Original address: http://www.cnblogs.com/RicCC/archive/2009/09/25/mysql.htmlStorage Engine Attribute MyISAM Heap BDB InnoDB Transactions No No Yes Yes Lock

Always keep decimals, calculation in the program is too cumbersome, but also to convert the operation. It is convenient to operate directly in the database.The data type is defined as Decimal/numeric type, the decimal place needs to be arbitrarily

The concept of querying data: Querying data, filtering data, determining what format the data is exported in.Second, the basic statement of data query1. Basic Statement format: Select field List from table or view where query condition2.1

Whether it is in the interview process, or in the future work, the SQL will be in the examination and use. So, the previous read some of the SQL knowledge points to summarize and record, is to play a role in a notebook. Friends who have not studied

1. Introduction to Stored Procedures The SQL statements that we commonly use to manipulate database languages need to be compiled and executed at the time of execution, while stored procedures (Stored Procedure) are sets of SQL statements that are

In the database, the index is a special object, it is a database structure that can speed up the data retrieval, it can quickly find the necessary content from the large amount of data, make the data query without retrieving the whole database. An

Original link: http://bbs.chinaunix.net/thread-4093341-1-1.htmlSync---criticalsection,mutex,event,semaphoressynchronization objects about threads can be divided into kernel objects and non-kernel objects, the biggest difference being that kernel

Limitations of the Category(1) A new instance variable cannot be added to the class, and the class has no location to hold the instance variable.(2) name conflict, where the category has a higher precedence when the methods in the category conflict

1. CSS cascading style sheets complement HTMLAchieve a thorough separation of web content and page effects1. Inline style sheet (sets the style of the element within the tag) Sunny day, good scenery everywhere More flexible, who want to set the data

A: Some ordinary selectorsDOCTYPE HTML>HTML>HeadLang= "en"> MetaCharSet= "UTF-8"> title>title> Linkhref= "Mycss.css"type= "Text/css"rel= "stylesheet">Head>Body>Derived selector instance -a>This is a div outside the style of a taga>Div> a>

First, Style type1. Between rows My inline CSS style. 　　2. Inline 3. ExternalSecond, selector type　　1. ID #id　　2, Class. class　　3. Label P4. General *5. Properties [type= "text"]6, Pseudo-class: hover7, Pseudo-element:: First-line8, sub-selectors,

　　　　　　　　　　　　　　　　　　　　　　　　　　　Non-parametric method of classTwo main characteristics of an object:Properties and MethodsMethod:The access modifier method returns a value type method name () { 　　　　　 //main body of the method}No parameter method: 　　 has

Two main characteristics of an object:Properties and Methods1. Method:The access modifier method returns a value type method name () {The body of the method}1.1 Non-parametric methodhas a return valueFor example: Public String play () {Return value

1. Two main characteristics of an object: properties and methods.2. Method: The Access modifier method returns a value type method name () {The body of the method｝3. No parameter method:(1) There is a return valueFor example: Public String play ()

Two main characteristics of an object:Properties and Methods1. Method:The access modifier method returns a value type method name () {The body of the methodPublic String Play () {}1. No parameter methodhas a return valueFor example:Public String

Today, a strange problem has occurred, the localhost access is not found 404, but there are 127.0.0.1 to access. The reason was finally found because Windows resolved localhost to IPv6 address: 1 instead of 127.0.0.1. Check the hosts to IPv6 has