Oracle ALTER TABLE modify column Syntax example__oracle

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For complete tips on Oracle ALTER TABLE syntax, click Easy Oracle Jumpstart. Oracle provides "ALTER TABLE" syntax to modify data columns In-place in this form:

ALTER TABLE
table_name
Modify
COLUMN_NAME datatype;

If you are are brave can use a single "ALTER TABLE" syntax to modify multiple columns:

ALTER TABLE
table_name
Modify
(
Column1_name Column1_datatype,
Column2_name Column2_datatype,
Column3_name Column3_datatype,
Column4_name Column4_datatype
);

Here is are some examples of Oracle "ALTER TABLE" syntax to modify data columns and, you can add constraints like NO T NULL:

ALTER TABLE
Customer
MODIFY
(
Cust_name VARCHAR2 (m) not NULL,
Cust_hair_color VARCHAR2 (20)
)
;

We can also use Oracle ' ALTER TABLE ' syntax in dynamic pl/sql to modify data columns

BEGIN
SQL_STRING := 'ALTER TABLE '||:TABLE_NAME||' MODIFY '||:COLUMN_NAME||' VARCHAR2(100)';  . . .
END;