Take the tour ×  To compare databases of different vendors
(Oracle, SQL Server, DB2, MySQL, and PostgreSQL) how can I
identify any object uniquely and do I need a catalog? For
instance, In Java's DatabaseMetadata I should specify catalog
and schema fooPattern at least.  Is it true that catalog is just
an abstraction of data storage?  share|improve this question add
comment  3 Answers  up vote 28 down vote accepted  In Oracle:
• server instance == database == catalog == all data managed by
same execution engine   • schema == namespace within database,
identical to user account   • user == schema owner == named
account, identical to schema, who can connect to database, who
owns the schema and use objects possibly in other schemas   • to
identify any object you need (schema name + object name)  In
PostgreSQL:    • server instance == db cluster == all data
managed by same execution engine   • database == catalog ==
single database within db cluster, isolated from other databases
in same db cluster   • schema =