How to modify field length in oracle

How oracle modifies the field length

Use the modify keyword to modify the data type: alter table table name modify field name data type ;

1. Data already exists in the table

ALTER table tableName MODIFY (字段名 字段类型(长度));

eg:

alter table dpsm_dm_drugslog modify(person VARCHAR2(30));

2. No data exists in the table:

ALTER TABLE TABLENAME MODIFY ID CHAR（16）

eg:

alter table dpsm_dm_drugslog modify person VARCHAR2(30);

Introduction to Oracle Database:

Oracle Database, also known as Oracle RDBMS, or Oracle for short. It is a relational database management system from Oracle Corporation. It is a product that has always been in the leading position in the database field. It can be said that the Oracle database system is currently a popular relational database management system in the world. The system has good portability, easy use, and strong functions. It is suitable for various large, medium, small, and microcomputer environments. It is a database solution with high efficiency, good reliability and adaptability to high throughput.

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