Oracle syntax lesson 1: Alter database commands

1. In order to add new column to a table:

                    ALTER TABLE   tbl_emp ADD col_name  VARCHAR2(160) NOT NULL ;

     2.  In order to add multiple new columns at once to a table:

       

                   ALTER TABLE   tbl_emp ADD

                   (

                      col_name1  VARCHAR2(160) NOT NULL,

                      col_name 2 VARCHAR2(30) NOT NULL

                   );

     3. In Order to rename a table name:

       

                  ALTER TABLE tbl_old_name RENAME TO tbl_new_name;

     4. In Order to Modify a column properties in a table:

                  ALTER TABLE tbl_name MODIFY 

                  (

                      col_name1 VARCHAR2(25) NOT NULL,

                      col_name2 number,

                      col_name3 VARCHAR2(100)

                   );

     5. In Order to Drop a column from a table:

                 ALTER TABLE tbl_name DROP COLUMN col_name1;

     6.  In Order to Rename a column in a table:

                  ALTER TABLE tbl_name  RENAME COLUMN col_old_name to col_new_name;

     7.  In Order to Change the password of a user:

             
                  ALTER USER myuser IDENTIFIED BY new_password;

     8.  In order to Lock a User Account:

                 ALTER USER myuser ACCOUNT LOCK;

     9.  In order to Unlock a User Account:

                 ALTER USER myuser ACCOUNT UNLOCK;

    10. In order to Expire the password of a User:

                ALTER USER myuser PASSWORD EXPIRE;