One of my fields in the data table was originally of type varchar2 and now I want to change it to Blob, why ca n’t I c

szj0571

One of my fields in the data table was originally of type varchar2 and now I want to change it to Blob, why ca n’t I change it?
How to deal with the content of a field with a length exceeding 4000? How should I read it?

whbilly

The type of varchar2 should be changed to Blob now?
clob

szj0571

How to store and read blob?

onlysnake

Blob is a lob (large object) data type, used to store large, unstructured data, such as binary files, picture files and other types of external files; lob type data can be stored directly within the data, also Can be stored in an external file. It will only point to the data locator. So you can not change the varchar2 (20) type to blob or clob type