mysqldump is a common tool for performing logical backups of MySQL databases. It generates SQL files containing CREATE and INSERT statements to rebuild the database. 1. It does not back up the original file, but converts the database structure and content into portable SQL commands; 2. It is suitable for small databases or selective recovery, and is not suitable for fast recovery of TB-level data; 3. Common options include --single-transaction, --databases, --all-databases, --routines, etc.; 4. Use mysql command to import during recovery, and can turn off foreign key checks to improve speed; 5. It is recommended to test backup regularly, use compression, and automatic adjustment.

InPHP,variablesarepassedbyvaluebydefault,meaningfunctionsorassignmentsreceiveacopyofthedata,whilepassingbyreferenceallowsmodificationstoaffecttheoriginalvariable.1.Whenpassingbyvalue,changestothecopydonotimpacttheoriginal,asshownwhenassigning$b=$aorp

The problem of unavailability of the printer driver can be solved through the following steps: 1. Check the connection and ensure that the printer is turned on and connected correctly; 2. Update or reinstall the driver, and download the latest version through the device manager or official website; 3. Turn off automatic driver updates to avoid conflicts; 4. Troubleshoot other factors such as system version, permissions and security software interference. Step-by-step processing in sequence usually restores normal printing function.

To safely handle PHP file uploads, you need to verify the source and type, control the file name and path, set server restrictions, and process media files twice. 1. Verify the upload source to prevent CSRF through token and detect the real MIME type through finfo_file using whitelist control; 2. Rename the file to a random string and determine the extension to store it in a non-Web directory according to the detection type; 3. PHP configuration limits the upload size and temporary directory Nginx/Apache prohibits access to the upload directory; 4. The GD library resaves the pictures to clear potential malicious data.

To set up asynchronous master-slave replication for MySQL, follow these steps: 1. Prepare the master server, enable binary logs and set a unique server-id, create a replication user and record the current log location; 2. Use mysqldump to back up the master library data and import it to the slave server; 3. Configure the server-id and relay-log of the slave server, use the CHANGEMASTER command to connect to the master library and start the replication thread; 4. Check for common problems, such as network, permissions, data consistency and self-increase conflicts, and monitor replication delays. Follow the steps above to ensure that the configuration is completed correctly.

When encountering phpMyAdmin timeout or upload restrictions, you usually need to adjust the PHP configuration. 1. Increase max_execution_time, if set to 300 seconds or 0 to release the time limit. 2. Adjust upload_max_filesize and post_max_size, if both set to 64M, and make sure post_max_size is slightly larger. 3. If you cannot edit php.ini, you can add the corresponding settings in .htaccess. After modification, restart the web server and take effect.

When the boot prompt is "Windows could not start because of the following fileismissing" 1. You can run bootrec/fixmb, bootrec/fixboot, bootrec/rebuildbcd through the Windows installation media; 2. Check the hard disk connection or use CrystalDiskInfo to detect the health status of the hard disk; 3. If there is a dual system, you can use the bootrec command to rebuild the boot or manually add the boot items; 4. Use PE environment to kill viruses and combine DISM and SFC tools to repair the system files, and the system can be restored in most cases.

To view the size of the MySQL database and table, you can query the information_schema directly or use the command line tool. 1. Check the entire database size: Execute the SQL statement SELECTtable_schemaAS'Database',SUM(data_length index_length)/1024/1024AS'Size(MB)'FROMinformation_schema.tablesGROUPBYtable_schema; you can get the total size of all databases, or add WHERE conditions to limit the specific database; 2. Check the single table size: use SELECTta