curious case of hyphen and dash

Question

I am trying to fetch records from Oracle 9i database whose value are 'FOO - BAR' for a particular column.

The 'FOO - BAR' condition values are present in the table, But when I run the query, the results are not coming.

After breaking my head for sometime, figured out that there is a difference in the size of the hypen's.

'FOO – BAR'
'FOO - BAR'

This time I copied (through SQLDeveloper) the DB value and pasted the value in Eclipse IDE. I did NOT see any difference in the Eclipse. When I run the query from IDE, to my surprise it worked and the values were coming.

I deployed the same class file to our servers(UX box), and again back to square no 1 - the values are not coming.

I gave a try changing the file encoding of my IDE from default(Cp1252) to UTF-8 and everything is fine now.

Can some one explain what's happening? Will the size of hyphen varies with encoding? do we have three different kinds of dashes?

Answer 1

There are plenty of different Unicode characters for em-dash, en-dash, hyphen etc. They're used in different contexts in text.

You may want to read the "Dash" wikipedia article for more information. Note that a hyphen isn't quite the same thing :)

As for how encodings come into things - it will depend on how you're inserting, retrieving and then displaying the data. I wouldn't start using cut and paste - that may very well try to find the closest available value to the actual data represented in the database.