Alter table: Changes the size of a column : Change Column Size « Table « Oracle PL / SQL






Alter table: Changes the size of a column



SQL> -- create demo table
SQL> create table Employee(
  2    ID                 VARCHAR2(4 BYTE)         NOT NULL,
  3    First_Name         VARCHAR2(10 BYTE),
  4    Last_Name          VARCHAR2(10 BYTE),
  5    Start_Date         DATE,
  6    End_Date           DATE,
  7    Salary             Number(8,2),
  8    City               VARCHAR2(10 BYTE),
  9    Description        VARCHAR2(15 BYTE)
 10  )
 11  /

Table created.

SQL>
SQL> -- display data in the table
SQL> select * from Employee
  2  /

no rows selected

SQL>
SQL>
SQL> desc employee;
 Name                                                                                                  Null?    Type
 ----------------------------------------------------------------------------------------------------- -------- --------------------------------------------------------------------

 ID                                                                                                    NOT NULL VARCHAR2(4)
 FIRST_NAME                                                                                             VARCHAR2(10)
 LAST_NAME                                                                                              VARCHAR2(10)
 START_DATE                                                                                             DATE
 END_DATE                                                                                               DATE
 SALARY                                                                                                 NUMBER(8,2)
 CITY                                                                                                   VARCHAR2(10)
 DESCRIPTION                                                                                            VARCHAR2(15)

SQL>
SQL> --Changes the size of the Salary column:
SQL>
SQL> ALTER TABLE Employee MODIFY (Salary number(11,2));

Table altered.

SQL>
SQL> desc employee;
 Name                                                                                                  Null?    Type
 ----------------------------------------------------------------------------------------------------- -------- --------------------------------------------------------------------

 ID                                                                                                    NOT NULL VARCHAR2(4)
 FIRST_NAME                                                                                             VARCHAR2(10)
 LAST_NAME                                                                                              VARCHAR2(10)
 START_DATE                                                                                             DATE
 END_DATE                                                                                               DATE
 SALARY                                                                                                 NUMBER(11,2)
 CITY                                                                                                   VARCHAR2(10)
 DESCRIPTION                                                                                            VARCHAR2(15)

SQL>
SQL>
SQL> select * from employee;

no rows selected

SQL>
SQL>
SQL>
SQL> -- clean the table
SQL> drop table Employee
  2  /

Table dropped.

SQL>
SQL>
SQL>
           
       








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1.Enlarge column width