Reconstruction of data is a part of backup files and it is done through the process of media recovery of Oracle relational database. The process of media recovery involved in restoring, rolling forward and rolling backward from backing up database options. In the later writings, we will be writing in detail about various processes associated with backup, recovery and how to decide which backup instance needs to be restored and the newer concept of flash recovery of data area.
Logical database structure:
Logical database structures are the front end of an Oracle database which deals with clients and application processes and aims to reduce the extra burden of the server. Logical database structure includes data blocks, extents, segments and empower database administrator have extreme control over the amount of disc space usages. Tablespaces are foremost units of Oracle database and it resides inside logical database structures. A single database unit is separated into logical storage units which are called as storage spaces.
It groups are similar and related logical structure of databases together into a single unit. Inside table space all application objects and processes are already grouped together and when particular data are stored inside a particular cyberspace, then that data automatically allotted to different application and processes for distribution of instances in particular dataset. It is a sort of artificial intelligence in working at separate tablespaces. It reduces extra burden on system administrators as well as reduce the workload on physical server computing of Oracle Database.
In short, each database is logically divided into different tablespaces. Each data files are exclusively created for each tablespaces on server to physically stored information of tablespaces in server. There are multiple instances of data files which are stored inside server. The combined size of exclusive size of data files that are stored inside server is known as logical size of tablespaces. Every Oracle database contains a system tablespace which has a small file size and it is automatically created when a new database is created for the first time.
With the creation of SYSTEM tablespace, another SYSAUX tablespace is created simultaneously. These are small tablespaces files and all the other information is stored in the logical structure of the database and these impact little on server capacity. It does not mean to say that you cannot create large tablespace files on server. Oracle allows you to create larger tablespaces files on server. Sometimes, many system administrators used to create single tablespace file consisting of all different aspects of tablespace file and this create a centralized tablespace file and this can remove confusions from system administrators while tracing an error logs whenever this happens from dump files.
In 64-bit systems, which help administrators to create ultra large tablespace files, it creates extremely easy facilities for clients who happen to find everything transparent while dealing with editing and modifying a database management system.