Oracle Storage Hierarchy (Photo credit: Wikipedia)During the installation of Oracle, the software files shall be placed in a directory called OracleHome directory. These files are called Oracle binaries and they are important for oracle to run properly. Once database software is installed many databases can be created using that. These databases are comprised of three types of files. One or more Data files, two are more Redo Log files, and one or more Control files.These files along with the binary files forms the physical structure of Oracle database.
Every database can have many users attached with it and every users have their own set of objects. These users are called schemas. These schemas shall be given space to store data using a structure named Tablespace. One Tablespace can be shared across many users. Every space occupying objects created by users are placed in tablespace. These objects are called Segments. Segments are broken into small units called Blocks. Blocks are the basic operational unit in oracle ie Every operations like i/o, space computation, etc... are based on blocks. For convenience oracle group blocks together namely extents for usage. Thus Schemas along with Tablespaces <- segments <- extents <- blocks forms logical structure of a database.
Every database can have many users attached with it and every users have their own set of objects. These users are called schemas. These schemas shall be given space to store data using a structure named Tablespace. One Tablespace can be shared across many users. Every space occupying objects created by users are placed in tablespace. These objects are called Segments. Segments are broken into small units called Blocks. Blocks are the basic operational unit in oracle ie Every operations like i/o, space computation, etc... are based on blocks. For convenience oracle group blocks together namely extents for usage. Thus Schemas along with Tablespaces <- segments <- extents <- blocks forms logical structure of a database.
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