How can we change the name and data type of a column of a
table?
Answer Posted / nithya
To change the name of the column:
ALTER TABLE TABLENAME RENAME COLUMN OLD_COLUMN_NAME TO
NEW_COLUMN_NAME;
eg: alter table employee rename column emp_name to ename;
To change the datatype of a column:
ALTER TABLE TABLENAME MODIGY COLUMN_NAME NEW_DATA_TYPE;
eg: alter table employee modify ename varchar(50);
NOTE: u cannot modify column of a datatype from larger value
to smaller value.U can do it only if there is no data in ur
column.
eg: alter table employ_detail modify emp_addr varchar(5);
ORA-01441: cannot decrease column length because some value
is too big
alter table employ_detail modify emp_id number(2)
ORA-01440: column to be modified must be empty to decrease
precision or scale
| Is This Answer Correct ? | 9 Yes | 4 No |
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