Database Management Systems

This is a system model based on a shared database that can be accessed by all sub-systems.

This type of models are based on loosely coupled entities that maintains their own state and operations.

It helps one to write java applications that manage the activity such as retrieving and processing the results received from the database in answer to your query.

Names and locations of data files and online redo log files entries are maintained in the control file.

This background process writes redo log entries to disk.

At specific time, all modified database buffers in the SGA are written to the data files by database writer. This event is called checkpoint.

This logical storage structure corresponds to a specific number of bytes of physical database space on disk.

Each session that issues a SQL statement has a private SQL area.

The contents of this memory components of the SGA are transferred periodically from memory to the online redo log files on disk by the log writer background process.

This memory component of the SGA prevents SQL statements from being repeatedly parsed thus improving performance during execution of SQL statements.

In this memory component of the SGA, blocks that need to be modified, are modified in memory and are written back to disk periodically.

In this mode of the SHUTDOWN command, after the transactions have been rolled back the user sessions are terminated.

The information in a rollback segment is used during database recovery to rollback uncommitted transactions for user.

These are used for batch processing.

This memory component of the PGA is used for operations such as hash-joins, bitmap create operations, etc.