Oracle Database provides information about all of the tables, views, columns, and procedures in a database. This information about the information is known as metadata. It is stored in two locations: data dictionary tables (accessed via built-in views) and a metadata registry.

Other relational database management systems support an ANSI-standard equivalent called information schema.

Warning: This is incomplete with respect to multiple datatypes including char, varchar and timestamp and uses extremely old, deprecated dictionary views, back to oracle 5.

SQL pattern match to a single character and should be escaped if you are in fact looking for an underscore character in the LIKE clause of a query.

Just add the following after a LIKE statement:


And then each literal underscore should be a double underscore: __


 LIKE '%__G' ESCAPE '_'

Oracle Metadata Registry

The Oracle product Oracle Enterprise Metadata Manager (EMM) is an ISO/IEC 11179 compatible metadata registry. It stores administered metadata in a consistent format that can be used for metadata publishing. In January 2006, EMM was available only through Oracle consulting services.