Just about two months after that post (on Nov 4, 2010 to be exact), I encountered this syntax structure in a PL/SQL Challenge quiz. To see the actual quiz, you will need to register (free) on the site. If you are into learning more about the database from the SQL and PL/SQL side of things in a simple quiz that takes a few minutes of time each day, I strongly suggest signing up and participating. You can find his blog discussion of this particular quiz at The quote character (q) and the 4 November quiz.
Using his wording as a starting point to search the Oracle documentation, I soon came across Text Literals. Somewhere along the way I saw that this was a 10g (10.1 I believe) addition. I went from 8.1 to 10.2, so it explains why I missed it.
It's pretty simple to use. Ignoring the national character version, you start with
q''
Within that, you put your delimiters. As the documentation says,
If the opening quote_delimiter is one of [, {, <, or (, then the closing quote_delimiter must be the corresponding ], }, >, or ). In all other cases, the opening and closing quote_delimiter must be the same character.
so we can setup structures such as
- q'[]'
- q'<>'
- q'##'
BEGIN dbms_output.put_line(q'{Here be the text with a ' in it}'); dbms_output.put_line(q'*Here be the text with a ' in it*'); dbms_output.put_line(q'#Random words put here#'); dbms_output.put_line(q'^Here be the text with a ' in it^'); END;
which produces
Here be the text with a ' in it Here be the text with a ' in it Random words put here Here be the text with a ' in it
Makes it a lot easier to put a single quote into a string than using double single quotes.
* Caveat *
Apparently the Text Literal process has issues with strings that contain 'n', where n' is at the end of the string. By that I mean the following will all run successfully
select q'[help'n ']' from dual; select q'['na']' from dual; select q'['a']' from dual;
select q'[help'n']' from dual; select q'['an']' from dual; select q'['n']' from dual;
No comments:
Post a Comment