How to set the primary key in oracle: 1. Define the primary key when creating the table, the code is [constraint TF_B_AIR_CONFIG_PK primary key (TYPE_ID)]; 2. After creating the table, use alter table syntax to set the primary key.
How to set the primary key in oracle:
1. What is the primary key
Primary key (primary key) is one or more fields in the table, and its value is used to uniquely identify a record in the table.
The so-called composite primary key means that the primary key of your table contains more than one field. If there is no unique primary key in the table, you can use a composite primary key to determine the uniqueness of a record.
2. Two ways to create a primary key
The first is to define the primary key when creating the table
Example of single-column primary key :
----创建TF_B_AIR_CONFIG表 create table ECS_STORE.TF_B_AIR_CONFIG( TYPE_ID VARCHAR2(20) not null, PROVINCE_CODE VARCHAR2(4) not null, PARAMETER_TYPE VARCHAR2(2) not null, LIMIT_NUM VARCHAR2(4) not null, EFFECTIVE_FALG VARCHAR2(2) default '1', UPDATE_TIME DATE default sysdate, constraint TF_B_AIR_CONFIG_PK primary key(TYPE_ID)--单列主键 )
Example of composite primary key:
----创建TF_B_AIR_CONFIG表 create table ECS_STORE.TF_B_AIR_CONFIG( TYPE_ID VARCHAR2(20) not null, PROVINCE_CODE VARCHAR2(4) not null, PARAMETER_TYPE VARCHAR2(2) not null, LIMIT_NUM VARCHAR2(4) not null, EFFECTIVE_FALG VARCHAR2(2) default '1', UPDATE_TIME DATE default sysdate, constraint TF_B_AIR_CONFIG_PK primary key(TYPE_ID , PROVINCE_CODE)--复合主键 )
Second, after creating the table, use alter table syntax
Syntax
ALTER TABLE table_name ADD CONSTRAINT constraint_name PRIMARY KEY (col1, col2,...coln);
Example
----创建TF_B_AIR_CONFIG表 create table ECS_STORE.TF_B_AIR_CONFIG( TYPE_ID VARCHAR2(20) not null, PROVINCE_CODE VARCHAR2(4) not null, PARAMETER_TYPE VARCHAR2(2) not null, LIMIT_NUM VARCHAR2(4) not null, EFFECTIVE_FALG VARCHAR2(2) default '1', UPDATE_TIME DATE default sysdate )
Related learning recommendations: oracle database learning tutorial
The above is the detailed content of How to set primary key in oracle?. For more information, please follow other related articles on the PHP Chinese website!
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
