Question

I have a pattern matching code in Java, which gets the pattern from database
When I was doing JUnit with mysql database everything went pretty cool

Original Pattern in database 
[a-zA-Z]{1}[0-9]{2}[a-zA-Z]{3}[0-9]{5}_[0-9]{4}-[0-9]{2}-[0-9]{2}-[0-9]{6}\\.csv
Mysql is retruning as expected and as it's stored.
Oracle is returning with extra backslashes 
[a-zA-Z]{1}[0-9]{2}[a-zA-Z]{3}[0-9]{5}_[0-9]{4}-[0-9]{2}-[0-9]{2}-[0-9]{6}\\\\.csv

Why it’s returning differently. Between am using hibernate to fetch the data.

Answer 1

In MySQL, \ is the escape character for strings, but that’s not true in Oracle. That means that this insert will work differently for each of them:

INSERT INTO PATTERNS (ID, VALUE) VALUES (1, '\\\\');

That will insert \\ in MySQL but \\\\ in Oracle. If you want to insert only \\ in Oracle, you have to change the insert to this:

INSERT INTO PATTERNS (ID, VALUE) VALUES (1, '\\');