You use the INSERT command to add rows to a table.
The standard INSERT command supports the following two ways to insert rows:
If you know all of the table columns and their internal physical order in DESCRIBE command, you don't need to specify column names after the table name in the INSERT command.
If you omit column names, you must provide precisely enough values and specify them in the correct order.
In the VALUES clause, you can specify a comma-separated list of literals or an expression.
You can use the reserved word NULL to specify a null value for a specific column.
You can specify the reserved word DEFAULT to instruct the Oracle DBMS to insert the default value associated with the corresponding column.
These default values are part of the table definition, stored in the data dictionary.
If you don't specify a value for a specific column in your INSERT statement, there are two possibilities:
The second way of using the INSERT command is to fill a table with a subquery.
These subqueries should produce the right number of values of the right data type.