Primary Key in Oracle

by Online Tutorials Library July 14, 2022

Primary Key

In Oracle, Primary key is the column which has unique values, and it cannot be null. In a table, there can be only one primary key.

Primary Key – Using CREATE TABLE statement

Syntax:

  CREATE TABLE table_name  (    column1 datatype null/not null,    column2 datatype null/not null,    …    CONSTRAINT constraint_name PRIMARY KEY (column1, column2, … column_n)  );  

Example

  CREATE TABLE Test2(ID Number, NAME Varchar2 CONSTRAINT test2_pk PRIMARY KEY (ID));  

Primary Key in Oracle

Primary Key – Using ALTER TABLE statement

Syntax:

  ALTER TABLE table_name  ADD CONSTRAINT constraint_name PRIMARY KEY (column1, column2, … column_n);  

Example

Primary Key in Oracle Using Alter Table

Drop Primary Key

Syntax:

Example

Primary Key in Oracle Drop Primary Key

Disable Primary Key

Syntax:

Example

Primary Key in Oracle Disable Primary Key

Enable Primary Key

Syntax:

Example

Primary Key in Oracle Enable Primary Key

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Primary Key in Oracle

Primary Key

Primary Key – Using CREATE TABLE statement

Syntax:

Example

Primary Key – Using ALTER TABLE statement

Syntax:

Example

Drop Primary Key

Syntax:

Example

Disable Primary Key

Syntax:

Example

Enable Primary Key

Syntax:

Example

Oracle Minus

BSD Based Operating System

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