Modify the field type in Oracle

Due to demand changes, we need to change the field type of A type NUMBER (8, 2) to char.

The general idea is as follows:

To change the name of a field of the type to backup, add a field with the same name as the field of the type to be changed (the original field has been renamed), update the data, and delete the field of the backup.

The following operations are performed in Oracle 10.2.0.1.0.

/* Modify the original field name */

Alter table name rename column field name TO field name 1;

/* Add a field with the same name as the original field */

Alter table name ADD field name VARCHAR2 (30 );

/*

Update the original data to a new field.

Note that data type conversion must be performed on the display (different from MSSQL)

*/

UPDATE table name SET field name = CAST (field name 1 AS VARCHAR2 (30 ));

/* Delete the original backup field */

Alter table Name drop column field name 1;