Basic concepts of SQL-commands and basic concepts of SQL
1,
MySQL(Structured query language) standard language 2 for accessing and processing Databases
What is SQL?SQL refers to the structured query language. SQL enables us to access databases (databases are warehouses that organize, access, and manage data according to data structures). SQL is an ANSI standard computer language,
What can SQL do?SQL for database query SQL for retrieving data from database SQL for inserting new records SQL for updating database data SQL for deleting records SQL for creating new database SQL for database create a new table SQL create a Stored Procedure SQL in the database create a view SQL in the database you can set table, stored procedure and view permissions 4, commonly used on terminals
Command(Desktop-based file management) touch + file name. file Type // create a file open + file name // open the corresponding file or folder ls // list all the files clear // clear the screen record mkdir + directory name // create directory (file) cp + parameters + source file + target file + copy/Move file rm + parameters + file // delete file cd .. /// return to the upper-level directory ping // send a response email to the current network host // read and send the email uname // display the information about the operating system who // list the current log on to all users whoami // display the currently operating user name df // display the total space and available space of the file system w // display the current console history // list the most recently executed several commands and numbers passed
