Hi - I need to update a VARCHAR2 column in a database and replace all occurances of a particular ascii character with another ascii character. These are not visible in the text as it's stored in the column. What functions can I use to do this type of replacement?
SELECT REPLACE('IT IS A STRING', CHR(65), CHR(66)) FROM dual;
It seems that you already know ASCII codes of those characters, so that shouldn't make a problem.
But, do you really mean "in a database", or is it just a table? If it is a whole database, you'll need a PL/SQL procedure which will loop through all tables and VARCHAR2 columns and - dynamically - using EXECUTE IMMEDIATE perform requested replacements.
If it is one table and a column, you can do that using an UPDATE statement in SQL.