Oracle SQL Plus The Definitive Guide- P8:Every day, computer professionals the world over wake up, travel to the office, sit down in front of a computer, and begin another day working with that database called Oracle. Programmers write queries and stored procedures. Database administrators monitor performance, make database changes, and perform other maintenance tasks. Operations people may need to back up or recover a database. | previous page page_47 next page Page 47 the CHANGE command had to be retyped each time. SQL Plus does not have any command recall capability. Now that line 3 is fixed up take another look at line 1. This time omit the L command and just type the line number in order to list the line SQL 1 1 SELECT employee_name time_log_name project_name Line 1 contains a bad column name which needs to be deleted. A variation of the CHANGE command where you don t supply any replacement text is used to do this. The following example shows how SQL C time_log_name 1 SELECT employee_name project_name At first glance the use of the CHANGE command to delete text may not seem very intuitive. It may help to think in terms of searching for a string in this case for time_log_name and replacing it with nothing. With the CHANGE command you can use delimiters other than the forward slash character. You just need to be consistent within the command. SQL Plus interprets the first nonspace character following the CHANGE command as the delimiter character. The following commands for example are all equivalent C FRUB FROM C FRUB FROM C XFRUBXFROMX The only time you would ever need to use a delimiter other than is if you needed to include a as part of the text to be searched for or replaced. You also have the option of leaving off the trailing delimiter so long as you aren t trying to include trailing spaces in your substitution string. The following two commands are equivalent C FRUB FROM C FRUB FROM However if your substitution strings contain spaces you do need to include the trailing delimiter. The following two commands will not produce equivalent results C FRUB FROM C FRUB FROM It s probably easiest to be in the habit of including the trailing delimiter all the time. You ll make fewer mistakes that way. previous page page_47 next page previous page page_48 next page Page 48 DEL The DEL command is used to erase one or more lines from the buffer. Used by itself it erases the current line. You .
