Download ORACLE: PL/SQL What is PL/SQL

An Introduction to Oracle
Victor Matos
1
What is ORACLE ?
• Very robust implementation of a
Relational Database Management
System (RDBMS)
The relational model of data is simple to
understand and has been extensively
scrutinized since 1970’s
2
What else is good about ORACLE ?
• The company is solid and successful,
since 1994 revenues in the order
of $2+ billion/year
• Very popular software,
worldwide distribution
• Runs in 100+ different
type of computers
3
Reasons for the Oracle Success
• Security Mechanisms users are given
specific rights to operate on the data.
• Backup and Recovery minimizes data loss
and idle time in the presence of failures
• Space Management flexible allocation
• Open Connectivity uninterrupted services
reachable from heterogeneous clients
• Development Tools
many to choose from
4
Parts of the Oracle Server
• Procedural Option: built-in programming
capabilities based on the PL/SQL language
• Stored Procedures: programs stored in the
server-side could be invoked using an ADAlike interface
• Triggers: dormant server-side routines
which are ‘fired’ when specific maintenance
conditions are met
5
Parts of the Oracle Server
cont
• Packages: libraries of server-side routines
including proc, functions, triggers, user
defined data types, constants, variables.
ORACLE
PACKAGES
Various
Clients
ORACLE
SERV ER
Same set of Proc,
functions, datatype, const, etc
6
Parts of the Oracle Server
cont
• Distributed Option: data could be stored in
different machines and placed in different
cities. Oracle Distributed option provides
location transparency, the user does not
need to be aware of where the data is kept.
7
Oracle Distributed Option
Cleveland, Ohio
Ohio
Inventory
Workstation
SELECT PartNumber, Price
FROM Ohio_inventory, suppliers
WHERE inv_sup = Sup_Numb;
Indians95 Oraccle Server
NETWORK
New York, NY.
Suppliers
Yankees96 ORACLE Server
8
Parts of the Oracle Server
cont
• Parallel Server Option:
Independent machines (nodes) which their
own memory and disk space could tap into
a common disk database. This loosely
coupled architecture provides data sharing
and message exchange between processes
9
Parallel Server Option
NODE 1
Cleveland, Ohio
NODE 2
New York, NY.
NY data
Ohio data
Shared
Database
Indians95 Oraccle Server
Yankees96 ORACLE Server
10
Parts of the Oracle Server
cont
• Parallel Query Option: Computers holding
more than one CPU (such as multiPentium
Windows NT) could use those processors in
solving independent portions of a query. An
Oracle control unit breaks the query into
pieces, and re-assembles the partial results.
11
Parallel Query Option
Cleveland, Ohio
Original SQL
statement
SELECT LastName, Dno
FROM Employee
WHERE (salary > 70000) or (sex = 'F')
Ohio data
Pentium 1
SELECT LastName, Dno
FROM
Employee
WHERE (salary > 70000)
Indians95 Oraccle Server
Dual Pentium
Window s NT4.0
Pentium 2
OR
SELECT LastName, Dno
FROM
Employee
WHERE (sex = 'F')
Results
12
ORACLE Products
SQL * Plus:
User-Friendly-Interface, superset of SQL
Oracle-Forms GUI interface (forms, menu, libraries)
Oracle-Reports Multimedia reporting (text, images, charts)
Oracle Loader Migration facilitator, legacy data to Oracle
Developer 2000 Integrated development environment:
Designer 2000 Forms, Reports, Graphics, Book, Browser,
Procedure builder, SQL*Plus, CASE
Personal Oracle Full version of the Oracle server for the PC
13
ORACLE Architecture
Terminology
An instance is a portion of the computers memory and a
collection of processes required by Oracle to operate
A database is the name of a reserved disk area
A tablespace is a collection of datafiles (or tables)
A table is a ‘file’ or container for application-specific data
14
ORACLE Architecture
Terminology:
Rollback is the action of setting a data item to its previous
value. For instance, assume an account holds $50, if a
deposit of $1000 on this account is not completed
the balance is set back to $50.
Undo is similar to roll-back, the action of resetting a data
item to its most recent previous value
Dirty-block is a memory resident image of a disk block
which has been changed by a process while in memory
LRU flushes from memory the block which for the longest
15
period of time has not been used
ORACLE Architecture
Physical Structure
Definition
Datafiles
Contain all of the database
data; logical structures ,
such as tables and indexes
Hold records of all changes
made to the database for
recovery purposes
Record the physical
structure and status of the
database
Contain startup values for
database parameters (often
referred as the init.ora file )
Redo Log Files
Control Files
Parameter File
16
ORACLE Architecture
A. What is inside of the database dictionary?
SQL> column comments format a35 wrap
SQL> select * from dictionary;
TABLE_NAME
COMMENTS
------------------------------ -----------------------------ALL_CATALOG
All tables, views, synonyms, and
sequences accessible to the user
ALL_CLUSTERS
Description of clusters
accessible to the user
ALL_CONSTRAINTS
Constraint definitions on acce
ssible tables
…
276 rows selected.
…
17
ORACLE Architecture
B. What is inside of a datafile?
SQL> describe
Name
----------NAME
TYPE
LINE
TEXT
user_source
Null?
-------NOT NULL
NOT NULL
Type
-------VARCHAR2(30)
VARCHAR2(12)
NUMBER
VARCHAR2(2000)
NOTE: You could use desc instead of describe
18
ORACLE Architecture
How to create objects in ORACLE
Objects in an ORACLE database are created in the following order
1. create database
2. create tablespace(s)
3. create rollback segment (s)
4. create user(s)
5. create table(s)
6. create index
7. create other objects such as: sequence, cluster, procedure, function,
package, trigger, link, profile, synonym, schema, snapshot, view, etc.
19
ORACLE Architecture
1. CREATE DATABASE Command
Used to create a database, making it available for general use,
with the following options:
o to establish a maximum number of instances, data files,
o redo log files groups, or redo log file members
o to specify names and sizes of data files and redo log files
o to choose a mode of use for the redo log
Warning: This command prepares a database
for initial use and erases any data currently in
the specified files. Only use this command when
you understand its ramifications.
20
ORACLE Architecture
CREATE DATABASE Command
create database Oracle
controlfile reuse
logfile 'D:\ORAWIN95\DATABASE\log1orcl.ora'
size 200K reuse,
'D:\ORAWIN95\DATABASE\log2orcl.ora'
size 200K reuse
datafile 'D:\ORAWIN95\DATABASE\sys1orcl.ora'
size 20M reuse autoextend on
next 10M maxsize 200M
character set WE8ISO8859P1;
21
ORACLE Architecture
CREATE DATABASE Command (details)
CONTROLFILE REUSE reuses existing control files identified by the initialization
parameter CONTROL_FILES
LOGFILE specifies one or more files to be used as redo log files.
MAXLOGFILES specifies the maximum number of redo log file groups that can ever be
created for the database.
MAXLOGMEMBERS specifies the max number of copies, for a redo log file group.
MAXLOGHISTORY specifies the max number of archived redo log files
for automatic media recovery of Oracle7 with the Parallel Server option.
MAXINSTANCES specifies the max number of instances that can simultaneously have
this database mounted and open.
22
ORACLE Architecture
CREATE DATABASE Command (details)
ARCHIVELOG In this mode, the contents of a redo log file group must be archived before
the group can be reused.
NOARCHIVELOG In this mode, the contents of a redo log file group need not be archived
before the group can be reused.
CHARACTER SET specifies the character set the database uses to store data.
DATAFILE specifies one or more files to be used as data files. These files all become part
of the SYSTEM tablespace.
AUTOEXTEND enables or disables the automatic extension of a datafile.
23
ORACLE Architecture
How to create a TableSpace
CREATE TABLESPACE MyTabspace_2
DATAFILE 'd:\ORAWIN95\DATABASE\MyData2.dat'
SIZE 10M
DEFAULT STORAGE (
INITIAL
10K
NEXT
50K
MINEXTENTS 1
MAXEXTENTS 999
PCTINCREASE 10)
ONLINE;
How to eliminate a tablespace
DROP TABLESPACE Mytabspace2
INCLUDING CONTENTS
CASCADE CONSTRAINTS;
24
ORACLE Architecture
Create additional tablespaces
-- USER_DATA: “Create user” command sets this as the default tablespace
-- TEMPORARY_DATA: Create user sets this as the temporary tablespace
-- ROLLBACK_DATA: For rollback segments
create tablespace user_data
datafile 'D:\ORAWIN95\DATABASE\usr1orcl.ora' size 3M reuse
autoextend on next 5M maxsize 150M;
create tablespace rollback_data
datafile 'D:\ORAWIN95\DATABASE\rbs1orcl.ora' size 5M reuse
autoextend on next 5M maxsize 150M;
create tablespace temporary_data
datafile 'D:\ORAWIN95\DATABASE\tmp1orcl.ora' size 2M reuse
autoextend on next 5M maxsize 150M;
25
ORACLE Architecture
Rollback_data
rbs1orcl
User_data
usr1orcl
usr2orcl
26
ORACLE Architecture
3. Create Rollback Segment
A rollback segment is an object that Oracle7 uses to store data
necessary to reverse, or undo, changes made by transactions.
Example
The following statement creates a rollback segment (rbs_temp)
with default storage values in the system tablespace:
CREATE ROLLBACK SEGMENT rbs_temp
TABLESPACE system;
27
ORACLE Architecture
Creating Rollback Segments
-- Create 16 rollback segments. Allows 16 concurrent users with open
-- transactions updating the database. This should be enough???.
create public rollback segment rb1 storage(initial 50K next 50K)
tablespace rollback_data;
create public rollback segment rb2 storage(initial 50K next 50K)
tablespace rollback_data;
…
create public rollback segment rb16 storage(initial 50K next 50K)
tablespace rollback_data;
28
ORACLE Architecture
Asking for the datafiles, and tablespaces in the current database
SQL> select file_name, tablespace_name, bytes
from
dba_data_files;
FILE_NAME
TABLESPACE_NAME
BYTES
------------------------------ ------------------------------ --------D:\ORA95\DATABASE\usr1orcl.ora
USER_DATA
3145728
D:\ORA95\DATABASE\rbs1orcl.ora
ROLLBACK_DATA
5242880
D:\ORA95\DATABASE\tmp1orcl.ora
TEMPORARY_DATA
2097152
D:\ORA95\DATABASE\sys1orcl.ora
SYSTEM
10485760
d:\ORA95\DATABASE\MyData2.dat
MYTABSPACE_2
10485760
DATABASE
USER
DATA
Rollback_
T emporary
Data
_
Data
System
Oracle
MYTABSPACE_2
Tablespaces
29
(under construction!)
Architecture Summary:
1- tablespace
2- redo log
3- control files
4- user proc
5- server proc
(dbwrt, ckpt, lgwr, smon, pmon, arch, lckn, reco)
6- sga (dict, datacache, redolog, sqlarea)
7- instances
30
SQL * Plus
SQL*Plus is a user-friendly-interface imitating
a notepad. Its primary use is in supporting
the construction of simple schema objects.
o Normally used to easily interact with the Oracle server
o Facilitates the prototyping of SQL commands
o ”Quick and dirty” way of developing/testing PL-SQL and
other Oracle objects
31
Using SQL * Plus to create Objects
Schema Objects
• users
•
•
•
•
•
•
•
tables
views
sequences
synonyms
indexes
clusters
hash clusters
Other schema objects such as packages, and triggers will be
discussed later.
32
Using SQL * Plus to create Objects
Create User Command
Creates a database user, or an account through which you can log in to the
database. You can optionally assign the following properties to the user:
•default tablespace
•temporary tablespace
•quotas for allocating space in tablespaces
•profile containing resource limits
Example: You can create the user MARIA by issuing the following statement:
CREATE USER Maria
IDENTIFIED BY Macarena
DEFAULT TABLESPACE payroll_ts
QUOTA 10M ON payroll_ts
QUOTA 5M ON temp_ts
QUOTA 5M ON system
PROFILE accountant;
Grant Connect, Resource to Maria;
33
Using SQL * Plus to create Objects
Schema Objects: TABLES
• Tables are the basic unit of data storage in an Oracle database.
• Data is stored in rows and columns.
• Typical datatypes are: CHAR, VARCHAR2, NUMBER, DATE
• A row is a collection of column information corresponding to a single
record.
• You can optionally specify rules for each column of a table. These rules
are called integrity constraints. Example: NOT NULL
• Once you create a table, you insert rows of data using SQL statements.
• Table data can then be queried, deleted, or updated using SQL.
34
Using SQL * Plus to create Objects
Create Table Command
Example I. To define the EMP table owned by SCOTT, you could issue
the following statement:
CREATE TABLE scott.emp (
empno
NUMBER
CONSTRAINT pk_emp PRIMARY KEY,
ename
VARCHAR2(10)
CONSTRAINT nn_ename NOT NULL
CONSTRAINT upper_ename CHECK (ename = UPPER(ename)),
job
VARCHAR2(9),
mgr
NUMBER
CONSTRAINT fk_mgr REFERENCES scott.emp(empno),
hiredate DATE DEFAULT SYSDATE,
sal
NUMBER(10,2) CONSTRAINT ck_sal CHECK (sal > 500),
comm
NUMBER(9,0) DEFAULT NULL,
deptno
NUMBER(2)
CONSTRAINT nn_deptno NOT NULL
CONSTRAINT fk_deptno REFERENCES scott.dept(deptno) )
PCTFREE 5
PCTUSED 75 ;
35
Using SQL * Plus to create Objects
Create Table Command
Notes
1- This table contains 8 columns. Ex: EMPNO column is of datatype NUMBER and has an
associated integrity constraint named PK_EMP.
2- HIRDEDATE column is of datatype DATE and has a default value of SYSDATE.
3- PCTFREE of 5 indicates that 5% of space is reserved for future updates
4- PCTUSED of 75, says that a minimum of 75% of the table should be used on each data block
5- The constraint on the mgr field indicates that such a value (mgr’s id) must also be found in
the scott.emp table (a recursive reference)
36
Using SQL * Plus to create Objects
Create Table Command. Typical data types
Data Type
Use
CHAR
Alpha-numeric,
Fixed data length
Alphanumeric,
variable-length
Numeric data:
Integers an float
Date data such as:
‘01-APR-97’
VARCHAR2
NUMBER
DATE
37
Using SQL * Plus to create Objects
Create Table Command.
Example II. Assuming you have the parallel query option, then the fastest method to create a
table that has the same columns as the EMP table, but only for those employees in department 10,
is to issue a command similar to the following:
CREATE TABLE emp_tmp
UNRECOVERABLE
PARALLEL (DEGREE 3)
AS
SELECT *
FROM
emp
WHERE deptno = 10;
Notes
1- The UNRECOVERABLE keyword speeds up table creation because there is no overhead in
generating and logging redo information.
2- Parallelism speeds up the creation of the table.
3- After the table is created, querying the table is also faster because the same degree of
38
parallelism is used to access the table.
ORACLE: PL/SQL
What is PL/SQL ?
• PL/SQL stands for Procedural extensions to SQL. It adds
programming capabilities to SQL.
•It is a block-structured language with a syntax similar to C
• Normally used on the server-side, however some client-side
products (ORA-FORMS) could also have it as a built-in part.
• It is not a stand-alone language
39
PL/SQL Architecture
CLIENT SIDE CODE
VisualBasic
Java
C, C++
COBOL
MS-Access
PowerSoft
People’s Soft
SAP
HTML + scripts
(JavaScript, Perl, VBS)
ORACLE SERVER
CODE
PL-SQL (Oracle 7, 8, 8i)
Java (Oracle8i)
...
40
PL/SQL Architecture
Client side
Third-Party
Products
Call tp
Stored
Procedures
ORACLE Forms
Local PL/SQL
Program
SQL
Generator
SQL
Statement
SQL
Statement
ORACLE
Server
SQL Statements
Processor
PL/SQL
Runtime
Engine
Call to
Stored
Proc
Call
to Stored
Proc
Stored Program Unit
PL/SQL V2.x
Runtime Engine
41
PL/SQL Programming
• PL/SQL = SQL + standard procedural programming
• Support for procedures, functions, flow-control statements,
declared variables, user-defined types.
• A PL/SQL program is either a procedure, a function, or an
anonymous block
• Anonymous blocks are nameless fragments of code normally
executed as script files
42
PL/SQL Programming
Block-Structure
Declaration Section
Execution Section
Exception Section
43
PL/SQL: Example1
-- CELCIUS1 (Lowest temp, Highest Temp) Converts Fahrenheit temperatures to Celcius. Results are saved
-- into TEMP, a table predefined to hold (number, number, text)
CREATE OR REPLACE
PROCEDURE Celcius1 (Low IN NUMBER, High IN NUMBER)
IS
Celcius
number;
Fahren
number;
Msg
varchar2(55);
BEGIN
DELETE FROM temp;
FOR Fahren IN Low..High LOOP
Celcius:= ROUND ( (Fahren -32)*5/9 );
IF (Fahren < 30 ) THEN
Msg := 'Too cold';
ELSIF (Fahren < 70 ) THEN
Msg := 'Cold';
ELSIF (Fahren <80) THEN
Msg := 'Very nice';
Create table Temp (…)
ELSE
Msg := 'Hot';
END IF;
INSERT INTO Temp VALUES (Fahren, Celcius, Msg);
END LOOP;
END;
44
PL/SQL: Example1
Test the program using the following SQL*PLUS commands
SQL> delete from Temp;
SQL> execute Celcius1(0,100);
SQL> select * from temp;
F1
F2
F3
--------------- ---------- -----------……
...
68
20
Cold
69
21
Cold
70
21
Very nice
71
22
Very nice
72
22
Very nice
73
23
Very nice
74
23
Very nice
75
24
Very nice
76
24
Very nice
77
25
Very nice
78
26
Very nice
79
26
Very nice
80
27
Hot
81
27
Hot
45
PL/SQL: Example1
A second way of testing a stored procedures is to call it from
an anonymous block. Type in the following code
sql>
edit CelciusTest
DECLARE
BEGIN
delete from Temp;
Celcius1 (0,100);
END;
sql> @celciusTest
sql> /
sql > select * from Temp;
46
PL/SQL: Example2
The COMPANY database
47
PL/SQL: Example2
-- WorkLoad
-- Employees are either assigned/removed to/from a project
CREATE or REPLACE
PROCEDURE WorkLoad ( p_action VARCHAR2,
p_ssn VARCHAR2,
p_pno NUMBER,
p_hours NUMBER:= 40 )
IS
BEGIN
IF (p_action = 'ASSIGN' ) THEN
INSERT INTO works_on VALUES (p_ssn, p_pno, p_hours);
ELSIF (p_action = 'REMOVE') THEN
DELETE FROM works_on WHERE (essn = p_ssn) AND
(pno = p_pno);
END IF;
END;
48
PL/SQL: Example2
Testing the procedure with an anonymous block.
SQL > edit workLoadTest
DECLARE
BEGIN
WorkLoad('ASSIGN',123456789,10,1.7);
END;
sql> @workLoadTest
sql> /
sql> select * from Works_On;
49
PL/SQL Programming
PL/SQL Syntax
Assignment
x := x + 1;
Condition
Testing
if (condition) then
[elsif (condition) then]
[else]
end if;
for i in -1..10 Loop ... end loop;
while (cond) Loop ... end loop;
Loop ... end loop
< ,<>, >, <= , >= , =
and, or, not
Loops
Conditions
50
PL/SQL Programming
Defining/Initializing Variables
Salary
DeptNumber
LastName
Sex
JobType
TaxDate
NUMBER(10,2);
NUMBER := 17;
VARCHAR2(20);
CHAR := ‘F’;
CHAR(15);
DATE := ‘15-APR-99’;
Most common data types are:
NUMBER, VARCHAR2, DATE
51
PL/SQL Programming
Defining Variables
%TYPE
Declares a variable with
respect to a Table.Column
Bonus
EMP.Sal%TYPE;
EMP
EMPNO
----7369
7499
7521
ENAME
---------SMITH
ALLEN
WARD
JOB
MGR HIREDATE
SAL
COMM
DEPTNO
--------- --------- --------- --------- --------- --------CLERK
7902 17-DEC-80
800
20
SALESMAN
7698 20-FEB-81
1600
300
30
SALESMAN
7698 22-FEB-81
1250
500
30
Number(7,2)
52
PL/SQL Programming
Defining Variables
%ROWTYPE
Defines a record with respect
to an existing table definition
TempEmp
EMP%ROWTYPE;
Refers to fields using: TempEmp.Salary
EMP
EMPNO
----7369
7499
7521
ENAME
---------SMITH
ALLEN
WARD
JOB
MGR HIREDATE
SAL
COMM
DEPTNO
--------- --------- --------- --------- --------- --------CLERK
7902 17-DEC-80
800
20
SALESMAN
7698 20-FEB-81
1600
300
30
SALESMAN
7698 22-FEB-81
1250
500
30
53
PL/SQL Programming
Creating/Debugging a Stored PL/SQL Function
This example shows how to create an debug a PL/SQL stored function using SQL*Plus
CREATE or REPLACE
FUNCTION IsFile ( MyTable IN VARCHAR2 ) RETURN ( boolean )
IS
result user_tables.table_name%TYPE;
BEGIN
Intentional
SELECT table_name INTO result
error
FROM
user_tables
WHERE table_name = UPPER(MyTable);
RETURN true;
EXCEPTION
WHEN No_Data_Found THEN RETURN false;
END;
/
54
PL/SQL Programming
Creating/Debugging a Stored PL/SQL Function
SQL> @isfile
Warning: Function created with compilation errors.
SQL> show errors
Errors for FUNCTION ISFILE:
Line and column where error was found
LINE/COL ERROR
-------- -------------------------------------------------1/47
PLS-00103: Encountered the symbol "(" when expecting
one of the following:<an identifier>
<a double-quoted delimited-identifier> LONG_ double
SQL> EDIT IsFile.sql
Use the editor to
correct each error in
the script file
55
PL/SQL Programming
Creating/Debugging a Stored PL/SQL Function
-- Testing ISFILE( ) function, using an anonymous block
-- Script: isFileTest. Author: V.Matos May 22, 1999.
clear screen
DECLARE
-- put file names here
theFile user_tables.table_name%TYPE := 'EMPXYZ';
BEGIN
delete from temp;
if ISFILE(theFile) then
insert into temp values (1,1, theFile || ' exists');
else
insert into temp values (2,2, theFile || ' does NOT exist');
end if;
END;
/
select * from TEMP;
clear buffer -- erase this line and try again
/
56
PL/SQL Programming
Testing the Anonymous Procedure
Running the anonymous script
SQL> @isFileTest
procedure successfully executed
SQL> select * from TEMP;
F1
F2
F3
---- ---- ---------------------2
2
EMPXYZ does NOT exist
Results are placed into the TEMP table
57
PL/SQL Programming
-- RaiseSalary: Function increases salary of certain employee by PctRaise
CREATE or REPLACE
FUNCTION RaiseSalary ( EmpSsn
number,
PctRaise number )
RETURN
number
IS
Default type is ‘IN’
NewSalary
number;
OldSalary
number;
BEGIN
SELECT Salary INTO OldSalary FROM Employee
WHERE SSN = EmpSSN;
NewSalary:= OldSalary * (1 + PctRaise);
UPDATE Employee SET Salary = NewSalary
WHERE SSN = EmpSsn;
RETURN NewSalary;
Returned value
EXCEPTION
WHEN No_Data_Found THEN
INSERT INTO temp VALUES (EmpSSN, ‘Not found’,Null);
RETURN -1;
58
END;
PL/SQL Programming
-- Anonymous proc. to test the RAISESALARY routine
-- Script: raiseSalaryTest
Author: VMatos 20-MAY-99
DECLARE
theSalary EMPLOYEE.SALARY%TYPE;
BEGIN
delete from TEMP;
theSalary := raiseSalary(123456789, 0.10);
insert into TEMP values (123456789, theSalary, NULL);
END;
/
select * from TEMP;
clear buffer
/
59
PL/SQL Programming
PROCEDURE which returns several results
CREATE or REPLACE
PROCEDURE GetEmpNameSal (
EmpSSN
IN number,
EmpName
OUT varchar2,
EmpSalary OUT number )
IS
BEGIN
select Lname ||', '|| Fname, Salary
into
EmpName, EmpSalary
OUT variables carry results
from
Employee
outside of the procedure
where SSN = EmpSSN;
EXCEPTION
WHEN No_Data_Found THEN
insert into TEMP
values (EmpSSN, ‘ERROR. Emp not found’,NULL);
EmpName:= '***';
EmpSalary:= -1;
END;
60
PL/SQL Programming
Testing the getEmpNameSal procedure.
-- Script: getEmpNameSalTest
DECLARE
theName TEMP.F3%TYPE;
theSalary EMPLOYEE.SALARY%TYPE;
BEGIN
delete from TEMP;
getEmpNameSal (123456789, theName, theSalary);
insert into temp
values (123456789, theSalary, theName);
END;
/
F1
F2
F3
--------------- ---------- -----------123456789
39930
SMITH, John
61
PL/SQL Programming
Anonymous Procedures
The following anonymous procedure performs the
following tasks:
• Executes stored proc. GetEmpNameSal to obtain the
name and salary of the employee whose SSN is
123456789. Results are saved into the TEMP table.
• Invokes the function RaiseSalary to increase the
employee’s salary by 10%. Again, a new line is added to
TEMP reporting the new salary value.
62
PL/SQL Programming
Anonymous Procedures
-- Name: Test2Routines.Sql
-- Anonymous Procedure to Test STORED routines
-- Uses: proc. GetEmpName,and func. RaiseSalary
-- table TEMP (already created with three columns)
DECLARE
Local memory variables defined to
EmpName
varchar(20);
store the Emp name and salary
mSalary
number;
retrieved using the stored procedure
BEGIN
DELETE FROM Temp;
GetEmpNameSal (123456789, EmpName, mSalary);
INSERT INTO Temp VALUES (123456789, mSalary, EmpName);
mSalary:= RaiseSalary(123456789, 0.10);
INSERT INTO Temp VALUES (123456789, mSalary, EmpName);
END;
63
PL/SQL Programming
Testing the Anonymous Procedure
Running the anonymous script
SQL> @ Test2Routines
procedure successfully executed
SQL> select * from TEMP;
F1
--------123456789
123456789
F2
--------30000
33000
F2
----------------Smith, John
Smith, John
Results are placed into the TEMP table.
64
PL/SQL Programming
Invoking a Stored Function from a SQL Query
•The numbers in the BASEBALL table are hard to read.
•A function BigBucks(...) is called to facilitate the reading of the big
numbers in the table
SQL> select * from BASEBALL;
PNAME
PSALARY
-------------------- -----------A. Belle
987654321
K. Griffey
1987654322
B. Bonds
1234567890
D. Cone
123456
P. Butterfingers
900
65
PL/SQL Programming
Do this just in case you do not have the BaseBall table!
drop table BASEBALL;
create table BaseBall (Pname varchar2(20),
PSalary varchar2(30));
insert
insert
insert
insert
insert
into
into
into
into
into
BaseBall
BaseBall
BaseBall
BaseBall
BaseBall
values
values
values
values
values
('A.
('K.
('B.
('D.
('P.
Belle',
987654321);
Griffey', 1987654322);
Bonds',
1234567890);
Cone',
123456);
Butterfingers', 900);
select * from BaseBall;
/
66
PL/SQL Programming
Invoking a Stored Function from a SQL Query
-- Playball.sql
-- This is a small SCRIPT (not an anonymous proc.)
-- The pretty function is called from the SQL comnd
column psalary format 99999999999
column bigbucks(psalary) format a30
select pname, psalary, BigBucks(psalary)
from
baseball;
SQL> @Playball
PNAME
PSALARY BIGBUCKS(PSALARY)
-------------------- ------------ --------------------A. Belle
987654321
987.65 Millions
K. Griffey
1987654322
1.99 Billions
B. Bonds
1234567890
1.23 Billions
D. Cone
123456
123.46 Thousands
P. Butterfingers
900
900.00 Peanuts
67
PL/SQL Programming
A Stored Function for Beautifying Big Numbers
Create or Replace
Function BIGBUCKS ( salary number ) Return varchar
IS
Billion
number := 1000000000;
Million
number :=
1000000;
Thousand number :=
1000;
LPAD( ) adds n spaces on
Message
varchar(30);
on left side of the string
Dollars
number(6,2);
begin
if (salary >= Billion) then
Dollars:= salary / billion;
message:= LPAD(to_char(dollars),8) || ' Billions';
return (message);
elsif (salary >= Million) then
Dollars:= salary / Million;
message:= LPAD(to_char(dollars),8) || ' Millions';
return (message);
elsif (salary >= Thousand) then
Dollars:= salary / Thousand;
message:= LPAD(to_char(dollars),8) || ' Thousands';
return (message);
Numeric format
else
message:= to_char(Salary,'999.00');
message:= LPAD(message,8)||' Peanuts';
return (message);
end if;
end;
68
PL/SQL Programming
Creating a Store Procedure: A dir-like Routine
1. Type the following code into a text file called: dirStor.sql
create or replace
PROCEDURE dirStor
IS
firstcol
boolean;
line varchar2(400);
tableName
varchar2(20);
columnName varchar2(20);
CURSOR data IS
select table_name, column_name
from
user_col_comments;
69
PL/SQL Programming
BEGIN
delete from dirList;
line:= ' ';
tableName:= ' ';
FOR d IN data LOOP
if (tableName <> d.table_name) then
if (line <> ' ') then
line:= line || ');' ;
end if;
insert into dirList values (line);
tableName:= d.table_name;
Line:= UPPER(d.table_name) || ' (' ;
firstcol:= true;
end if;
if NOT (firstcol) then
line:= Line || ', ';
end if;
firstcol:= false;
line:= line|| LOWER(d.column_Name);
END LOOP;
line:= line || ');' ;
insert into dirList values (line);
END;
70
PL/SQL Programming
Type-in the following lines into a file called: dir.sql. Put the
file in the directory c:\bin\orawin95
-- Script: dir.sql
execute dirStor
select * from dirList;
NOTE: dirList is a user-created table. You need to make the
table before using it. Type the following SQL statement:
CREATE TABLE dirList ( MyTables VARCHAR2(80) );
71
PL/SQL Programming
An example of how to use the dir routine is given
below:
SQL> @dir
PL/SQL procedure successfully completed.
MyTables
---------------------------------------------------------------DEPARTMENT (dname, dnumber, mgrssn, mgrstartdate);
DEPENDENT (essn, dependent_name, sex, bdate, relationship);
MYLOG (num1, msg);
TEMP (F1, F2, F3);
PROJECT (pname, pnumber, plocation, dnum);
WORKS_ON (essn, pno, hours);
7 rows selected.
72
PL/SQL Programming
Writing a Procedure to (a) Securely Insert Works_On records
(b) Verify Potential Business Rules
The procedure Insert_WorksOn() is invoked to add new records to the Works_On table
in a very controlled way. Each call to the function provides the programmers
authentication code and data (SSN, ProjNumb, Hour). For example:
Result:= Insert_WorkOn(‘Dilbert’,123456789,10,40)
If the programmer ‘Dilbert’ is not in the list of peoples authorized to make insertions,
the operation is rejected and MYLOG file is update with a rejection message
• If the SSN and PNO provided are already in the Works_On table the current insertion
is rejected and the log file is updated
• The function returns a numeric code 1, -1, -2, etc. to indicate the status of the execution.
This number is stored into the variable Result (1: success, negative values: problems).
73
PL/SQL Programming
To execute the examples in this section you may
need to do the following DML changes.
create table WORKS_ON (
essn
char(9),
pno
number,
hours
number(5,1),
CONSTRAINT pk_workson_key PRIMARY KEY (essn, pno));
drop table Valid_Operators;
create table VALID_OPERATORS
(Operator_Name varchar2(20) );
insert into VALID_OPERATORS values ('Dilbert');
insert into VALID_OPERATORS values ('Calbert');
74
PL/SQL Programming
create or replace
FUNCTION Insert_WorksOn (
Programmer_Id
EmployeeSsn
ProjectNumber
WeeklyHours
varchar2,
number,
number,
number )
RETURN number
IS
Programmer_Name
varchar(20);
Message
varchar(70);
BEGIN
-- First block: Is the programmer allowed to insert records?
-- Note: All code goes into one BEGIN...END block.
BEGIN
select Operator_Name into Programmer_Name
from
Valid_Operators
where Operator_Name = Programmer_Id;
EXCEPTION
when No_Data_Found then
Insert into Mylog values (Programmer_Id,
'ERROR** unauthorized used of function');
RETURN -1;
END;
-- first block
75
PL/SQL Programming
-- INSERTWORKSON cont.
-- Second block: Here other conditions could be checked
-- before accepting record into the works_on table
BEGIN
insert into Works_On values
(EmployeeSsn, ProjectNumber, WeeklyHours);
RETURN 1;
EXCEPTION
When DUP_VAL_ON_INDEX then
Message:= ' Emp ' || to_char(EmployeeSsn) ||
' already in proj '
||
to_char(ProjectNumber);
insert into Mylog values (NULL, Message);
RETURN -2;
When Others then
Message:= ' Emp ' || to_char(EmployeeSsn) ||
' not assigned to ' ||
to_char(ProjectNumber);
insert into Mylog values (NULL, Message);
RETURN -3;
END; -- second block
END;
76
PL/SQL Programming
--TESTING THE INSERT_WORKSON FUNCTION
DECLARE
theResultCode NUMBER;
BEGIN
delete from mylog;
theResultCode := Insert_WorksOn ('Dilbert', 123456789, 10,1.2);
insert into mylog values ('123456789 workson 10', theResultCode);
END;
COL1
COL2
---------------------- ----------------------------------Emp 123456789 already in proj. 10
123456789 workson 10
-2
Mylog
ESSN
PNO
HOURS
--------- --------- --------123456789
1
32.5
123456789
2
7.5
123456789
10
1.2
Employee
77
PL/SQL Programming
Writing a Secure Procedure to Delete a Works_On record
The procedure Delete_WorksOn() is invoked to remove records from the
Works_On table. In the function-call the programmers authentication code
and the Works_On key field(s) are supplied. For example: in the following
call, programmer ‘Dilbert’ asks to remove employee 123456789 from proj. 1.
Result:= Delete_WorkOn(‘Dilbert’,123456789,1)
• If the programmer ‘Dilbert’ is not authorized to make such a deletion, the
operation is rejected and MYLOG file is update with a rejection message
• If employee 123456789 is not in the Works_On table the current deletion is
rejected and the log file is updated otherwise, the record is eliminated
• The function returns a numeric code 1, -1, -2, etc. to indicate the status of
the execution. (1: success, negative values: problems).
78
PL/SQL Programming
create or replace
FUNCTION Delete_WorksOn ( Programmer_Id varchar2,
EmployeeSsn
number,
ProjectNumb
number )
RETURN number
IS
Programmer_Name
varchar(20);
Message
varchar(70);
BEGIN
-- First block: Verify that programmer is allowed to delete
-- Note: all code goes in one BEGIN...END block
BEGIN
select Operator_Name into Programmer_Name
from
Valid_Operators
where Operator_Name = Programmer_Id;
EXCEPTION
when No_Data_Found then
Message:= 'Programmer not allowed to ' ||
'delete Works_On rec.';
Insert into Mylog values(Programmer_Id, Message );
RETURN -1;
79
END;
-- first block
PL/SQL Programming
-- DELETE_WORKSON script cont.
---Second block: Other conditions could be checked here
-- before deleting the record
BEGIN
delete from Works_On
where Essn= EmployeeSsn
AND
Pno = ProjectNumb;
if (sql%notfound) then
Message:=' ** ' || to_char(EmployeeSsn) ||
' / ' || to_char(ProjectNumb) ||
' not found ';
insert into Mylog values (NULL, Message);
RETURN -2;
end if;
RETURN 1;
80
PL/SQL Programming
-- DELETE_WORKSON script cont.
---Second block: Other conditions could be checked here
-- before deleting the record
EXCEPTION
When Others then
Message:= ' *** ' || to_char(EmployeeSsn) ||
' remains in Works_On';
insert into Mylog values (NULL, Message);
RETURN -3;
END; -- second block
END;
81
PL/SQL Programming
-- DELETE_WORKSON script cont.
---Second block: Other conditions could be checked here
-- before deleting the record
--TESTING THE DELETE_WORKSON FUNCTION
DECLARE
theCode Number;
BEGIN
delete from mylog;
theCode := delete_WorksOn ('Dilbert', 123456789, 10);
insert into mylog values ('After delete ', theCode);
END;
/
select * from mylog;
select * from works_on where essn like '123%';
/
82
PL/SQL Programming
Writing a Secure Procedure to Update Project records
The procedure Update_Project( ) is used to modify existing records in the Project table.
Individual records are located using the Pnumber values as search-key. The updating of
projects occurs in the context of a function call such as the example bellow.
The arguments passed to the function are: Programmer_Id, project number, name, location;
and number of responsible department.
Result:= Update_Project(‘Dilbert’,1,‘Cerveza XXX’,‘Margarita’,NULL);
•
•
•
•
•
•
•
Each project record to be updated must include the project number
More than one field could be updated in a single function call
Project numbers are not changeable (instead delete whole rec. and re-insert with a new number)
If the programmer ‘Dilbert’ is authorized to make deletion, the operation is rejected
If there is no record for project number 1, the current update is rejected
If a field is not going to be updated, the word NULL must be written in the proper column
The function returns a numeric code 1, -1, -2, etc. to indicate the status of the execution.
83
PL/SQL Programming
Writing a Secure Procedure to Update Project records
create or replace
FUNCTION Update_Project( Programmer_Id
ProjectNumber
ProjectName
ProjectLocation
DepartmentNumber
RETURN number
IS
Programmer_Name
varchar2(20);
Message
varchar2(70);
VarPnumber
number;
number,
number,
varchar,
varchar,
number )
84
PL/SQL Programming
Writing a Secure Procedure to Update Project records cont.
BEGIN
-- First block: Is programmer allowed to update projects?
-- NOTE: all code goes in one BEGIN...END block
BEGIN
select Operator_Name into Programmer_Name
from
Valid_Operators
where Operator_Name = Programmer_Id;
EXCEPTION
when No_Data_Found then
Message:= 'Programmer not allowed to ' ||
'update Projects';
Insert into Mylog
values (Programmer_Id, Message);
RETURN -1;
END;
-- first block
85
PL/SQL Programming
Writing a Secure Procedure to Update Project records cont.
-- Second block: Verify there is a project record matching
-- Pnumber key. If the field is not NULL, modify using given
-- parameter
BEGIN
select Pnumber into VarPnumber from
Project
where Pnumber= ProjectNumber;
if (ProjectName is not NULL) then
update Project
set
Pname= ProjectName
where Pnumber = ProjectNumber;
end if;
if (ProjectLocation is not NULL) then
update Project
set
Plocation= ProjectLocation
where Pnumber = ProjectNumber;
End if;
if (DepartmentNumber is not NULL) then
update Project
set
Dnum = DepartmentNumber
where Pnumber = ProjectNumber;
End if;
86
RETURN 1 ; -- success !
PL/SQL Programming
Writing a Secure Procedure to Update Project records cont.
-- Deal with Update problems here
EXCEPTION
When No_Data_Found then
Message:= ' Project ' ||
to_char(ProjectNumber) ||
' does not exist ';
insert into Mylog values (NULL, Message);
RETURN -2;
When Others then
Message:= ' Project '
||
to_char(ProjectNumber)
||
' can not be updated ';
insert into Mylog values (NULL, Message);
RETURN -3;
END; -- second block
END;
87