Oracle 11g Regular Expression Implementation

PL/SQL and SQL began supporting these text search and comparison operations in the Oracle 10g database release. The Oracle 11g database supports IEEE Portable Operating System Interface (POSIX) standard draft 1003.2/D11.2, and Unicode Regular Expression Guidelines of the Unicode Consortium. Oracle 11g extends matching capabilities for multilingual data beyond the POSIX standard. This release also adds support for the common Perl regular expression extensions that are not covered in and don't conflict with the POSIX standard.

Oracle 11g introduces a restrictive subordinate expression to the REGEXP_INSTR (regular expression in-string) and REGEXP_SUBSTR (regular expression substring) functions, which were introduced in Oracle 10g. Oracle 11g also adds the REGEXP_COUNT (regular expression count) function.