Tablespace

A tablespace (Eng. table space ) designated in the database area the location is written to the tables, indexes and other data objects. The database management system (DBMS ) can be accessed in two different ways to store:

• SMS tablespace - System Managed Storage: The storage medium is through operating system functions.
• DMS tablespace - Database Managed Storage: The DBMS does the memory management itself

SMS are easy to manage. Your limits are set by the operating system.

DMS, however, can be individual files, which divides the DBMS internally then. Depending on the system, but there may be parts of devices (partitions) or entire devices ( raw devices ) are managed by the DBMS. The administration costs increase, inter alia by the fact that the area does not increase automatically when needed. But that often accompanies a higher processing speed, since both the rights management is shifted completely to the DBMS, and the selection of data to be cached. The DBMS can often better decide which data are likely to need multiple ( complex cache strategies through the buffer pool ).

It differs in principle four types of tablespaces:

• Regular (tables and indexes)
• Temporary (sorting, reorganizing )
• LARGE (for large objects such as BLOB, CLOB, IMAGES, etc.)
• System catalogs ( for example, contains tables in which the data types are defined)

• Databases