In-depth explanation of how to use SQL Plus (login and common commands)

SQL Plus is a command line tool used for interactively executing SQL statements in Oracle databases. Here is a detailed explanation on how to use SQL Plus, including login and common commands.

1. Log in to SQL Plus:
   Open the command line terminal and enter the following command to log in to SQL Plus:
2. Connect to the database using the specified username and password.
3. In this case, the username is the user’s name in the database, the password is the user’s password, and the database is the connection string for the database.
4. Change current mode:
   To change the current mode, use the following command:
5. Change the current schema to ‘schema_name’ in the session.
6. One of these is the name of the schema to switch to.
7. Execute SQL statement:
   In SQL Plus, you can directly input SQL statements and execute them. For example, enter the following command to execute a simple query:
8. retrieve all data from the table called table_name.
9. To show the table structure, you can use the following command:
10. Show the structure of the table named “table_name”.
11. The table_name is the name of the table for which the structure is to be displayed.
12. To exit SQL Plus, you can use the following command:
13. leave.
14. Store output results:
    You can use the following command to save the query results to a file:
15. Save the output to the file specified by file_name, then select all records from table_name, and finally stop saving the output.
16. file_name is the name of the file where the results will be stored.
17. Clear the screen:
    You can use the following command to clear the output on the screen:
18. refresh the screen;
19. To view the help document, you can use the following command in SQL Plus:
20. Can you lend a hand?

These are detailed explanations of some commonly used commands and login processes in SQL Plus. With these commands, you can execute SQL statements, and perform database management and querying operations in SQL Plus.