oracle primary key | Primary Key - oracle tutorial - sql tutorial




Oracle create table with only primary key

Learn oracle - oracle tutorial - Oracle create table with only primary key - oracle examples - oracle programs

What is oracle primary key ?

  • A primary key is a single field or combination of fields that uniquely defines a record.
  • A primary key column cannot contain NULL values.
  • Most tables should have a primary key, and each table can have only ONE primary key.
  • Oracle primary key

    Oracle primary key and foreign key

Syntax:

CREATE TABLE table_name
(
  column1 datatype null/not null,
  column2 datatype null/not null,
  ...

  CONSTRAINT constraint_name PRIMARY KEY (column1, column2, ... column_n)
);
click below button to copy the code. By - oracle tutorial - team
Oracle constrains primary key

Learn oracle - oracle tutorial - Oracle constrains primary key - oracle examples - oracle programs

oracle tutorial , sql tutorial , sql , pl sql tutorial , oracle , pl sql , plsql

Example:

CREATE TABLE wikitechy_emp(
emp_id number(1) PRIMARY KEY,
emp_name varchar(20),
emp_designation varchar(20))
click below button to copy the code. By - oracle tutorial - team

Creating Primary key in the Table:

 Oracle primary key query
  1. In the create table statement, PRIMARY KEY constraint is applied for emp_id column.
 Oracle primary key insert query
  • We are inserting id value 1, name value as ARUN and designation value as project manager into a wikitechy_emp table using insert into keyword.
 Oracle primary key insert query with another values
  • Here, when we insert a same value for emp_id which you have already inserted in your first row. The unique constraint (PRIMARY KEY) reject your insertion of data into the wikitechy_emp table and shows a violated message.

This tutorial provides an indepth knowledge on the following items such as oracle tutorial , sql tutorial , sql , pl sql tutorial , oracle , pl sql , mysql tutorial , sql tutorial for beginners , learn sql , oracle database tutorial , sql query tutorial , oracle dba tutorial , plsql tutorial , oracle tutorial pdf , oracle pl sql tutorial , oracle sql tutorial , sql tutorial point , oracle tutorial for beginners , learn oracle online free , learn oracle online , learning pl sql programming , learn sql online for free , sql learning online , dba oracle tutorial , oracle sql tutorial advanced , oracle 11g dba tutorial with examples , oracle online learning , oracle learning online , how to learn pl sql , sql coding tutorial , sql learning websites , sql basic learning

Related Searches to oracle primary key | Primary Key