Declaring a Variable by Reference : Introduction « PL SQL Programming « Oracle PL/SQL Tutorial

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Oracle PL/SQL Tutorial
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24.PL SQL Programming
25.Cursor
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27.Function Procedure Packages
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29.SQL PLUS Session Environment
30.System Tables Data Dictionary
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32.Object Oriented
33.XML
34.Large Objects
35.Transaction
36.User Privilege
Oracle PL/SQL Tutorial » PL SQL Programming » Introduction 
24.1.11.Declaring a Variable by Reference
declare
    variable_name  table.column%TYPE;
    variable_name2 variable_name%TYPE;
    variable_row   table%ROWTYPE;
begin

The following code shows some examples of defining datatypes:


SQL> -- create demo table
SQL> create table Employee(
  2    ID                 VARCHAR2(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> -- prepare data
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2               values ('01','Jason',    'Martin',  to_date('19960725','YYYYMMDD'), to_date('20060725','YYYYMMDD'), 1234.56'Toronto',  'Programmer')
  3  /

row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values('02','Alison',   'Mathews', to_date('19760321','YYYYMMDD'), to_date('19860221','YYYYMMDD'), 6661.78'Vancouver','Tester')
  3  /

row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values('03','James',    'Smith',   to_date('19781212','YYYYMMDD'), to_date('19900315','YYYYMMDD'), 6544.78'Vancouver','Tester')
  3  /

row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values('04','Celia',    'Rice',    to_date('19821024','YYYYMMDD'), to_date('19990421','YYYYMMDD'), 2344.78'Vancouver','Manager')
  3  /

row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values('05','Robert',   'Black',   to_date('19840115','YYYYMMDD'), to_date('19980808','YYYYMMDD'), 2334.78'Vancouver','Tester')
  3  /

row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary, City,        Description)
  2                values('06','Linda',    'Green',   to_date('19870730','YYYYMMDD'), to_date('19960104','YYYYMMDD'), 4322.78,'New York',  'Tester')
  3  /

row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary, City,        Description)
  2                values('07','David',    'Larry',   to_date('19901231','YYYYMMDD'), to_date('19980212','YYYYMMDD'), 7897.78,'New York',  'Manager')
  3  /

row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary, City,        Description)
  2                values('08','James',    'Cat',     to_date('19960917','YYYYMMDD'), to_date('20020415','YYYYMMDD'), 1232.78,'Vancouver', 'Tester')
  3  /

row created.

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


ID   FIRST_NAME           LAST_NAME            START_DAT END_DATE      SALARY CITY       DESCRIPTION
---- -------------------- -------------------- --------- --------- ---------- ---------- ---------------
01   Jason                Martin               25-JUL-96 25-JUL-06    1234.56 Toronto    Programmer
02   Alison               Mathews              21-MAR-76 21-FEB-86    6661.78 Vancouver  Tester
03   James                Smith                12-DEC-78 15-MAR-90    6544.78 Vancouver  Tester
04   Celia                Rice                 24-OCT-82 21-APR-99    2344.78 Vancouver  Manager
05   Robert               Black                15-JAN-84 08-AUG-98    2334.78 Vancouver  Tester
06   Linda                Green                30-JUL-87 04-JAN-96    4322.78 New York   Tester
07   David                Larry                31-DEC-90 12-FEB-98    7897.78 New York   Manager
08   James                Cat                  17-SEP-96 15-APR-02    1232.78 Vancouver  Tester

rows selected.

SQL>
SQL>
SQL> declare
  2      v_empno1 employee.id%TYPE;
  3      v_empno2 v_empno1%TYPE;
  4      v_emp_rec employee%ROWTYPE;
  5  begin
  6      NULL;
  7  end;
  8  /

PL/SQL procedure successfully completed.

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

Table dropped.

SQL>
SQL>
SQL>
24.1.Introduction
24.1.1.Writing a simple program
24.1.2.Each complete line of the PL/SQL code must end with a semicolon (;).
24.1.3.Anonymous Block Structure
24.1.4.An example of an anonymous block.
24.1.5.Anonymous blocks can be nested in the procedure and exception blocks in as many levels as you want
24.1.6.The Lexical Set of Elements
24.1.7.Delimiters
24.1.8.Comments
24.1.9.Multi-line comments start with /* and end with */.
24.1.10.Declaring variables
24.1.11.Declaring a Variable by Reference
24.1.12.There are some restrictions on the declaration of variables:
24.1.13.Assigning values to variables
24.1.14.Assign SQL query results to PL/SQL variables
24.1.15.Literals as variable values
24.1.16.Examples of Integer and Real Literals
24.1.17.Numeric literals cannot contain dollar signs or commas, but they can be written in scientific notation
24.1.18.Character and string literals in the Oracle world are enclosed by single quotes
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