New added columns are empty : Alter Table « Table « Oracle PL/SQL Tutorial






SQL> create table employee(
  2    employee_id     number(9),
  3    first_name      varchar2(15),
  4    last_name       varchar2(20),
  5    email           varchar2(25),
  6    constraint pk_employee primary key (employee_id)
  7  );

Table created.

SQL>
SQL> insert into employee
  2  values (1, 'Tom', 'Kyte', 't@aaa.com');

1 row created.

SQL>
SQL> insert into employee
  2  values (2, 'Sean', 'Dillon', 's@aaa.com');

1 row created.

SQL>
SQL> insert into employee
  2  values (3, 'Christopher', 'Beck', 'c@aaa.com');

1 row created.

SQL>
SQL> commit;

Commit complete.

SQL>
SQL> select *
  2  from employee;


EMPLOYEE_ID FIRST_NAME           LAST_NAME            EMAIL
----------- -------------------- -------------------- -------------------------
          1 Tom                  Kyte                 t@aaa.com
          2 Sean                 Dillon               s@aaa.com
          3 Christopher          Beck                 c@aaa.com

3 rows selected.

SQL> alter table employee
  2  add (
  3    phone_number    varchar2(10)
  4  )
  5  /

Table altered.

SQL>
SQL> select *
  2  from employee;


EMPLOYEE_ID FIRST_NAME           LAST_NAME            EMAIL                     PHONE_NUMB
----------- -------------------- -------------------- ------------------------- ----------
          1 Tom                  Kyte                 t@aaa.com
          2 Sean                 Dillon               s@aaa.com
          3 Christopher          Beck                 c@aaa.com

3 rows selected.

SQL> drop table employee;

Table dropped.

SQL>
SQL>








6.3.Alter Table
6.3.1.Altering a Table
6.3.2.Some of the aspects of a column you can modify using ALTER TABLE
6.3.3.Adding a Column
6.3.4.ADD initially_created DATE DEFAULT SYSDATE NOT NULL;
6.3.5.Changing the Size of a Column
6.3.6.Decrease the length of a column
6.3.7.Changing the Precision of a Numeric Column
6.3.8.Decrease the precision of a numeric column
6.3.9.Changing the Data Type of a Column
6.3.10.Fill data into new added table column
6.3.11.Changing the Default Value of a Column
6.3.12.Alter table to add new constraint for new added column
6.3.13.ALTER TABLE to DISABLE a CONSTRAINT
6.3.14.Alter table to add primary key
6.3.15.Alter table to add primary key across more than one columns
6.3.16.Dropping a Column
6.3.17.New added columns are empty
6.3.18.Alter table to add unique with tablespace and storage setting
6.3.19.Alter table to add primary key with tablespace and storage setting
6.3.20.alter table nologging