ORACLE DBA BLOG

  Tables ·          Tables are the basic unit of data storage in an Oracle Database. Data is stored in rows and columns. ·          You define a table with a table name, such as employees , and a set of columns. You give each column a column name, such as employee_id , last_name , and job_id ; a datatype, such as VARCHAR2 , DATE , or NUMBER ; and a width. ·          The width can be predetermined by the datatype, as in DATE . If columns are of the NUMBER datatype, define precision and scale instead of width. ·            A row is a collection of column information corresponding to a single record. ·          You can specify rules for each column of a table. These rules are called integrity constraints. One example is a NOT NULL integrity constraint. This constraint f...

 Linux : Linux is one of popular version of UNIX operating System It is the interface between the user and the hardware. It performs a variety of tasks including file handling, memory management, controlling hardware devices, process management and many more. There are various versions of Unix: Solaris Unix, HP Unix, AIX, etc. Linux is is free and open source. Unix/Linux   is popular in enterprise-level because it supports multiple user environment. Linux Operating System has primarily three components. 1.       Kernel 2.       Shell Kernel: Kernel is the core of the operating system that controls all the tasks of the system . It consists of various modules, and it interacts directly with the underlying hardware. Kernel provides the required abstraction to hide low level hardware details to system or application programs.   It contains all the basic, low-level things that are needed to make the compute...