access invalid use of null

Tags: parent mys default edit error exists save reason LEDScenario: MySQL adds a parent_id column to the table and sets it to not NULL, saving the Times wrong invalid use of NULL value.Cause of error: Because the parent_id of the existing data column is null, the setting con

Tags: using database query use Set MAT conflict Delete number new1. Description of the problem Use database query statement "ALTER TABLE information modify ' number ' varchar (255) NOT NULL ' because you want to change the" number "column in the" Information "table to non-null You can change the other columns, but only

Tags: default value error. com val MySQL article own others wrongTabular data I will not give, the specific reason is still: The default value is not set at the beginning of not NULL, and later want to modify the times wrong, because the modification will affect the initialization of many values of the settings, and not uniform, there may be columns allowed to be empty, and some columns are not allowed to be empty. At this point, the following operati

Today's new site found in the Chrome browser, through localhost access is valid, but through the native IP even 127.0.0.1 access is not valid,The error in the report is that the Request Invalid HostNameSo that the site through two computers access, debugging encountered a small resistanceHere's how to fix it:1. In the

location for memory release.Before the -- leak-check = Yes parameter is added and the memory leakage error is no longer displayed, you may need to modify the code multiple times, the software without memory leakage was born like this :-). When valgrind is run, add the -- show-reachable = Yes parameter to find free or new matching results in the future. The output results are similar to those above, but more unreleased memory is displayed.Use valgrind to find

Document directory Use valgrind to find Memory leakage and Invalid Memory Access Valgrind is a multi-purpose code analysis and memory debugging tool for x86 Linux. You can run your program in its environment to monitor memory usage, such as malloc and free in C language or new and delete in C ++. If you use uninitia

I encountered a Website access problem when I was working in the China Telecom Industry this summer and kept it recorded in my technical warehouse. At that time, IIS6 was used to build an ASP Website environment. when accessing ASP files, the following information is displayed: You are not authorized to view this page. HTTP Error 401.1-unauthorized: access is denied due to

This type of problem is often encountered in WinForm programming, resulting in the inability of worker threads to assign a value to a control1 //Defining Delegates2 3 Private Delegate voidSettextcallback (stringtext);4 5 6 7 //The following method is called when assigning a value to TextBox1.Text8 9 Private voidSetText (stringtext)Ten { One //invokerequired need to compare call thread ID and create thread ID A //returns True if they are not the same -

1. After installing VS2015,. NET Framework4.6 replaces the C:\Windows\Microsoft.NET\Framework64\v4.0.30319 (if using a Windows7 64-bit version) of the file, Projects that cause VS2013 to be browsed in IIS will see the following error:2. A long time, flipping through a large number of search data can not be resolved, and finally set the application pool in IIS "enable 32-bit application" is true, then open the site, everything is back to normalLeave a date for the check!After you install visual S

error Because the Redis service is self-booting, it will not start again, so loading the configuration file is a failure. There is also no Redis boot small box (below the picture, slowly looking down), note that the Windows version of the Redis installation, the default boot loaded configuration file is redis.windows-service.conf, as shown in:2. Invalid passwordAlthough the password is set in the configuration file (redis.windows.conf), the password

since future projects will use Spring boot technology as the theme, these days have tried Springboot+dubbo to complete the layering of business architectures, this article mainly records the Dubbo null pointer problems encountered during SPRINGBOOT construction. First, we recommend that you have a channel to this problem and take a look at this articleHttp://www.oschina.net/question/1011127_144093?fromerr=7

installed in the previous project. At that time, there was no problem. I did not expect that this installation encountered some problems. When using Oranavi for installation, the system prompts that the Oracle user has no permission to execute the Oracle Installation program. Therefore, the Oracle Installation program file permission is completely released, and the result is the same. Then I consulted the support engineer and found the problem lies in the directory of the Oracle installer file.

Problem description fopen (), file_get_contents (), getimagesize () and so on are not normal access to the content of the network, the specific performance of any parameter is a URL, all return null value If Windows can be found Allow_url_fopen Open If Linux can Recompile php, remove the –with-curlwrapper parameter--before compiling remember to perform make clean first. When Windows was not opening th

One, because a Web page access in the project involves multiple certificates, each certificate only needs to be bypassed, but we cannot tell when the certificate was changed. Therefore, the method of the Internet is always unable to solve the problem perfectly. The following methods can be commonly encountered in a variety of situations, but also very grateful to netizens closure to provide me with this method.@property nsurlrequest *failedrequest;@pr

This error occurs when I use a desktop to dial up the Internet. Solve the problem and find that China Telecom will bind the Mac NIC address of the dial-up user for the first time, and it will be OK to configure the MAC address of the desktop to my notebook! Error 691 indicates that the user, password, or domain is incorrectly resolved. Step 1. the user password is correct. modify the NIC binding address, the entered value is automatically converted to

an error. Figure E The access project does not support NZ functions. Use NZ in Access Project NZ cannot be used in the project, but should be replaced by the isnull function of transact SQL. This function is similar to NZ in the following form: Isnull (expression, valueifnull) Both parameters are required. The type of isnull

Tags: java ofo param name span OLE ret target serverOne, what is cross-domain accessFor a chestnut: In a site, we want to use Ajax to get specific content from the B site. Cross-domain access issues occur if the A site is not in the same domain as the B site. You can understand that two domain names cannot cross a domain name to send requests or request data, otherwise it is unsafe. Cross-domain

When I use C # To save an access data, the system prompts that the data types are inconsistent. When data is stored An error occurred. "Microsoft Office Access cannot append all records in the append query. Microsoft Office Access Field 1 is set to null beca

") ); }); Lambda expression Simpler Action AT1 = new Action (() = {richtextbox1.appendtext ("update \ n");}); This. Invoke (at);Here this. Executes this method on behalf of a thread on the current form (control)This is not necessarily the case, as long as the controls on the current form are available, such asButton1. Invoke (at);This. Invoke (at);//invoke: Executes the specified delegate on the thread that owns the underlying window handle for this control.Richtext

The control cannot be accessed across threads after the. Net2. , the control on the form is created by the current main thread, and when the user executes a method asynchronously: Assign a value to the control on the form in the method, remember: When executing an asynchronous delegate, it is actuallyis to open a thread to execute that method, which will cause an error: the operation between threads is invalid: it is accessed from a thread that does n