When a style sheet defines a style, you can define the ID and define class, for example:
Id Method: #test {color: #333333}, calling Class method:. Test{color: #333333}, calling ID A page can be used only once, class can be referenced multiple times.
Some netizens asked, ID and class as if nothing different, I used in the page with multiple IDs in IE show also normal, with multiple IDs what effect?
Ans
In the development often encountered to put multiple IDs together with a symbol to separate the incoming database, that split is a big dealSELECTNpushid into#Temp fromTable1WHERE CHARINDEX(',' + CONVERT(VARCHAR(Ten), NCOULMN)+ ',',',' + '3305,3311,3314' + ',')> 0SELECT * from#TempThe columns here are for the int type, so you want to convert.For orders that order the master-slave table, from the table multiple names are stitched together--Instanc
Table structureRequirements: ID and name name may be repeated multiple times. But with only one ID, you need to find the most repeated names and IDs. There are several names that can repeat the most, each with a different ID.SELECT t.id,t.name,a.nu from TLeft JOIN(SELECT Id,name,count () as Nu from-t GROUP by NAME) A on T.name=a.nameJOIN(SELECT id,name,count () As num from T GROUP by NAME ORDER by num DESC LIMIT 1) CWHERE A.nu=c.numThere is a better w
1 CREATEDefiner=' Sa ' @ '%`PROCEDURE' Proc_product_leimu_parentids ' (2 inchPidINT3 )4 BEGIN5 SELECTT2.id, T2. Name from(SELECT @r as_ID, (SELECT @r:=ParentID fromProduct_leimuWHEREId=_ID) asParentID,@l:= @l + 1 asLvl from(SELECT @r:=Pid@l:= 0) VARs, Product_leimu HWHERE @r 0) T16 JOINProduct_leimu T2 ont1._id=T2.idORDER byT1.lvlDESC;7 ENDMySQL Gets the collection of all the parent category IDs and name of the subcategory IDMySQL gets the col
This is a previously encountered SQL interview problem, for reference learning:Find project IDs where all project start times are smaller than previous project end timesMysql> Select * fromT2;+----+---------------------+---------------------+|Id|Start| End |+----+---------------------+---------------------+| 1 | -- on- on xx:xx:xx | -- on- in xx:xx:xx || 2 | -- on- on xx:xx:xx | -- on- A xx:xx:xx || 3 | -- on-Geneva xx:xx:xx |
and then restarts immediately. This command is handy when configuring the application, which can be executed when the configuration file is modified to restart the process.--------------------------------------------------------------------------------* Lore Kill-9 PIDConsent of the Kill-s SIGKILLThis powerful and dangerous command forces the process to terminate abruptly at run time, and the process cannot clean itself up after the end. A hazard is a system resource that is not normally releas
Microtime functionDescription: Returns the current UNIX timestamp and number of microsecondsSyntax: Mixed microtime ([bool $get _as_float])Direct output echo microtime ();//Get the following: 0.26672100 1585622985 Front is the current microsecond number, followed by the normal timestamp, separated by a space in the middle//If with parameters (Boolean parameter) echo Microtime (True) ;//Output result: 1585623020.7408 The number of microseconds that have just been shown in the form of floating-poi
Look up the Internet, there are a lot of ways
1, MD5 (Time (). Mt_rand (1,1000000));
This method has a certain probability that there will be repetition
2. PHP built-in function uniqid ()
The Uniqid () function generates a unique ID based on the current time in microseconds.
The W3school reference manual says: "The IDs generated through this function are not optimal because of the system time." If you want to generate an absolutely unique ID, use
Write a program, open 3 threads, the IDs of the 3 threads are a, B, C, each thread prints its own ID on the screen 10 times, the output must be displayed in the order of ABC, such as: Abcabc .... recursion in turn. #include #include The results are as follows:
Objective
Protecting your data requires a trade-off between security and access capabilities. How do you find the most appropriate way?
At present, the company and government have established strict standards for the auditing and control of data, which makes database security a hot spot recently. DBAs must ensure that users have access to the data needed to complete their work while avoiding data risk.
The only way to absolutely protect the data is to shut down the server and lock it up and k
Phenomenon:Barnyard2 after running for a period of time, it stops itself, and no related logs are found in/var/log/barnyard2 or/var/log/suricata.Investigation:The following records exist in/var/log/messageKERNEL:BARNYARD2[3747]: Segfault at the IP 0000003e5ea226e0 SP 00007fffdf3d65a8 error 4 in Libmysqlclient.so.16.0.0[3e5ea 00000+136000]Judging by this may be the problem of libmysqlclient.so.16.0.0.Solve:Attempt to replace the new libmysqlclient.so.16.0.0 is not valid, causing Barnyard2 to not
Often some perfectionists ask me, how to let the database's self-increment field in the record is deleted when the order to reset them, not to discuss whether such a toss is really necessary, just talk about the solution, there is a need for friends to see.Method 1, delete the self-increment field, and then rebuild (the disadvantage is that you must remember other properties of the self-increment field, otherwise it may cause some unknown problems)ALTER TABLE ' tablename ' DROP COLUMN ' id ';ALT
In jquery, you can easily use CSS class names and IDs to get elements.
For example:
1 ID: #id
$ (' #ida ')-selects all elements with an ID of IDA, regardless of the tag name of the element.
$ (' Div#ida ')-Select all div tag elements with id Ida.
2 Class:.classname
$ ('. ClassA ')-Select the class name to have a classA of all elements, regardless of their label name.
$ (' Div.classa ')-Select the class name that has a classA for all DIV elements.
Th
varchar( -)) when LEN(@Id)= 2 Then 'Crad000000' + CAST(@Id as varchar( -)) when LEN(@Id)= 3 Then 'Crad00000' + CAST(@Id as varchar( -)) when LEN(@Id)= 4 Then 'Crad0000' + CAST(@Id as varchar( -)) when LEN(@Id)= 5 Then 'Crad000' + CAST(@Id as varchar( -)) when LEN(@Id)= 6 Then 'Crad00'
First, the MyBatis version must be 3.3.1 and aboveThe version of the MyBatis that the project relies on must be 3.3.1 and above, the lower version is not, and the version of the jar that ensures that the dependent mybatis of the HAP project needs to be the required version:Second, @param annotations cannot be used in the DAO layer, and the list variable is used in the Mapper.xml file to receive collections in the DAO layerDatabase Library structure Design:The corresponding DTO layer:The correspo
1. Create a table to save the largest ID nowSELECT [Id],[prefix],[code] from [Documentno]2. Increase the SP, using the lock table, generate the corresponding IDCreate PROCEDURE [dbo].[Generaldocumentno]( @preFix nvarchar( the), @outCode varchar( the) output) asBEGIN-- =============================================--Author:xiefs--Create date:2013-12-18--Description: Generate system unique serial number-- =============================================Declare @docNo nvarchar( the), @month varc
Tags: select databaseUpdate Dept B, (select Group_concat (T.deptid), Group_concat (d.deptname separator '/') as Dname, T.id, t.deptname from (sel ECT Substring_index (Substring_index (A.deptid, ', ', b.help_topic_id+1), ', ', -1) as DeptID, a.ID, A.deptname from (select D.father as DeptID, D.id, D.deptname from Dept D) a join Mysql.help_topic B on b.help_topic_id GROUP by ID, deptname) C set b.location=c.dname where b.id = C.idEffectCopyright NOTICE: This article for Bo Master original article,
Not sure which solution is good
In the book to see that is generally a sub-table query, in favor of caching
Reply content:
Not sure which solution is goodIn the book to see that is generally a sub-table query, in favor of caching
Mainly look
This is a creation in
Article, where the information may have evolved or changed.
Preface
In languages such as C/c++/java, we can directly obtain the thread ID, and then by mapping the thread ID and the two-level dispatch task ID relationship, you
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