When you encounter the "DefaultGatewayisNotAvailable" prompt, it means that the computer cannot connect to the router or does not obtain the network address correctly. 1. First, restart the router and computer, wait for the router to fully start before trying to connect; 2. Check whether the IP address is set to automatically obtain, enter the network attribute to ensure that "Automatically obtain IP address" and "Automatically obtain DNS server address" are selected; 3. Run ipconfig/release and ipconfig/renew through the command prompt to release and re-acquire the IP address, and execute the netsh command to reset the network components if necessary; 4. Check the wireless network card driver, update or reinstall the driver to ensure that it works normally.

If the second monitor is not recognized by Windows, first check whether the cable and interface are normal, try to replace the HDMI, DP or VGA cable, confirm the plug-in video output port, and test different interfaces to eliminate compatibility issues; then verify the monitor power and input source settings, and connect the monitor separately to test whether it can be recognized; then enter the Windows display settings and click the "Detection" button, or use Win P to switch the display mode, and update the graphics card driver at the same time; finally check the graphics card specifications to confirm whether it supports multi-screen output to avoid exceeding its maximum output capability.

MySQL supports transaction processing, and uses the InnoDB storage engine to ensure data consistency and integrity. 1. Transactions are a set of SQL operations, either all succeed or all fail to roll back; 2. ACID attributes include atomicity, consistency, isolation and persistence; 3. The statements that manually control transactions are STARTTRANSACTION, COMMIT and ROLLBACK; 4. The four isolation levels include read not committed, read submitted, repeatable read and serialization; 5. Use transactions correctly to avoid long-term operation, turn off automatic commits, and reasonably handle locks and exceptions. Through these mechanisms, MySQL can achieve high reliability and concurrent control.

Character set and sorting rules issues are common when cross-platform migration or multi-person development, resulting in garbled code or inconsistent query. There are three core solutions: First, check and unify the character set of database, table, and fields to utf8mb4, view through SHOWCREATEDATABASE/TABLE, and modify it with ALTER statement; second, specify the utf8mb4 character set when the client connects, and set it in connection parameters or execute SETNAMES; third, select the sorting rules reasonably, and recommend using utf8mb4_unicode_ci to ensure the accuracy of comparison and sorting, and specify or modify it through ALTER when building the library and table.

When encountering the "SYSTEM_SERVICE_EXCEPTION" blue screen error, you do not need to reinstall the system or replace the hardware immediately. You can follow the following steps to check: 1. Update or roll back hardware drivers such as graphics cards, especially recently updated drivers; 2. Uninstall third-party antivirus software or system tools, and use WindowsDefender or well-known brand products to replace them; 3. Run sfc/scannow and DISM commands as administrator to repair system files; 4. Check memory problems, restore the default frequency and re-plug and unplug the memory stick, and use Windows memory diagnostic tools to detect. In most cases, the driver and software problems can be solved first.

When Windows cannot detect a second monitor, first check whether the physical connection is normal, including power supply, cable plug-in and interface compatibility, and try to replace the cable or adapter; secondly, update or reinstall the graphics card driver through the Device Manager, and roll back the driver version if necessary; then manually click "Detection" in the display settings to identify the monitor to confirm whether it is correctly identified by the system; finally check whether the monitor input source is switched to the corresponding interface, and confirm whether the graphics card output port connected to the cable is correct. Following the above steps to check in turn, most dual-screen recognition problems can usually be solved.

This article provides the download and installation steps of Ouyi computer version client. 1. Visit the official website; 2. Find the download portal; 3. Select the corresponding version; 4. Download and install; 5. Log in to use to ensure that users can quickly complete transaction operations on the PC side.

When encountering the problem of "You need permission to perform this operation", it is usually because the Windows permission management mechanism restricts the operation. The solutions include: 1. Run the program as an administrator, right-click to select "Run as an administrator" and confirm the UAC prompt; 2. Obtain file/folder ownership, change the owner to the current user in "Properties → Security → Advanced" and replace the subcontainer; 3. Adjust the permission settings, and give yourself "full control" permissions through "Properties → Security → Edit"; 4. Check whether the file is occupied, close the relevant programs or use Unlocker and LockHunter to unoccupi. Try it one by one to solve the problem.