2004 presentation 600

8/9/2019 2004 Presentation 600

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9i PL/SQL Fundamentals9i PL/SQL Fundamentals

Judi Hotsinpiller, OCP

The University of Utah

Administrative Computing ServicesPaper 600

http://www.acs.utah.edu/acs/

[email protected]


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Session Agenda

PL/SQL Principles

PL/SQL Definition

Compile Environment

Subprograms Block Flow

Data Types Scalar

Composite Data types SQL Cursors

Implicit

Explicit


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Session Agenda Continued

Exceptions

Merge

Conditional Logic

Case Expressions Loops

Executing PL/SQL

Summary


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PL/SQLPrinciples

Procedural Language/SQL

Procedural Language/Structured QueryLanguage Oracles procedural extension to SQL

Modern software engineering features Looping

Conditional logic

Exception handling Data encapsulation

Information hiding

Object orientation


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PL/SQL Definition

Procedural Language extensions to SQL

Oracle product extension to other tools

Extension of SQL Power to create complex 3GL type programs

Cache results of SQL statements with cursors

Loop through the results allowing manipulation Object Oriented Programming with Packages


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Compile Environment

Three execution engines in the Oracle Server

SQL Statement Executor

Procedural Statement Executor

Java Statement Executor

PL/SQL is an interpreted language

Syntax errors caught logic errors are not

SQL> show errors

Use bind variables to return results to SQL*Plus


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FlowPL/SQL

PL/SQL Engine

SQL Engine

PL/SQL Block

Procedural Statements

Procedural

Statement

Executor

SQL Statement Executor

SQL Statements


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Subprograms

Anonymous blocks

Three sections

Declaration Execution

Exception


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Anonymous Block Example

DECLAREemp_name emp.ename%TYPE;

total_salary NUMBER;

invalid_emp EXCEPTION;

BEGIN

total_salary :=

get_sal (emp_name, TOTAL);

IF total_salary IS NULLTHEN

RAISE invalid_emp;

ELSE

DBMS_OUTPUT.PUT_LINE

(Annual Salary to date ||

TO_CHAR (total_salary));

END IF;EXCEPTION

WHEN invalid_employee

THEN

...

END;


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Named PL/SQL BlocksProcedures, Functions, Packages, and Triggers

Stored at DB Server with nameshared

Procedures

Named block of PL/SQL code

iSQL*Plus example of invoking a procedure

SQL> EXECUTE emp_raise (176) Invoking from within another procedure

emp_raise (176);

Invoking from within an Anonymous PL/SQL block

DECLARE

v_empid emp.empno%type;

BEGINemp_raise (v_empid);

COMMIT;

END;


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Named PL/SQL Blocks

Functions

PL/SQL block that accepts arguments andcomputes a value and returns it

Packages

Packages are the way you can bundlesubprograms, items, and types into one

location Triggers

Application Trigger or database Trigger


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Calling a Function from a SQL

CREATE OR REPLACE FUNCTION tax_rate(p_amount in number)

RETURN NUMBER IS

BEGIN

RETURN (p_amount * 0.675);

END tax_rate;

/

SELECT empno, name, sal, tax_rate(salary)

FROM emp

WHERE tax_rate(sal) > (SELECT MAX(tax_rate(sal)

FROM emp

WHERE deptno = 10)

ORDER BY tax_rate(sal) DESC;


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Packages

Bundle subprograms, items, and types into one location Built-in Packages

dbms_SQLOPEN_CURSOR

PARSE

BIND_VARIABLE

EXECUTEFETCH_ROWS

CLOSE_CURSOR

CREATE OR REPLACE PROCEDURE ddlproc (tablename varchar2, colsvarchar2) AS

cursor1 INTEGER;

BEGIN

cursor1 := dbms_sql.open_cursor;dbms_sql.parse(cursor1, 'CREATE TABLE ' || tablename ||

' ( ' || cols || ' )', dbms_sql.v7);

dbms_sql.close_cursor(cursor1);

end;

/ (Note:1008453.6 Metalink)


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Built in Packages Continued

dbms_ddl Embed SQL commands ALTER, COMPILE, and ANALYZE

dbms_ddl.alter_compile

dbms_ddl.analyze_object

dbms_job Scheduling of PL/SQL Programs

dbms_job.submitVARIABLE job_no is NUMBER

BEGIN

DBMS_JOB.SUMIT(

job => :job_no,

what => OVER_PACK.ADD_DEPT(EDUCATION, 2710);,

next_date => TRUNC(SYSDATE + 3),

interval => TRUNC(SYSDATE + 3));

New PL/SQL supplied packages in 9i


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Triggers

Database Trigger

DML Trigger

Row

Fires each time the table is affected Statement

These are useful when trigger action does notdepend on the data

Form Builder Triggers Executed only within a particular Form Builder

application


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BlockFlow

Basic element of the code structure

Declaration Contains all of the variables, constants, cursors, and user-

defined exceptions

Executable SQL statements to manipulate the data

Exception What to perform when an error is raised


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Data Types

Scalar

Four basic scalar data types

Number

Character Boolean

Date/Time


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Data Types--Scalar

Number [(precision, scale)]

Number without length will allocated 23 spaces

Char[(maximum_length)]

Base type variable for fixed-length character VarChar2(Maximum_length)

Base type for variable-length character


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Data Types Continued

Long

LONG is used to store variable-length strings

Long Raw

Is not interpreted in PL/SQL. Boolean

TRUE, FALSE, or NULL.

LOB

Graphic objects stored out of line. Date

Base type for date and time


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Data Types Continued

Example:

DECLARE

v_job_title VARCHAR2(15);

v_number_employ BINARY_INTEGER :=0;v_total_tax NUMBER(9,2) :=0;

v_orderdate DATE := SYSDATE + 7;

c_tax_rate CONSTANT NUMBER (3,2)

:= 5.75;v_flag BOOLEAN NOT NULL

:= TRUE;


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%TYPE Attribute

Handy attribute--declare a data type to match

underlying database object column

Example:

DELARE

v_emp_name emp.name%TYPE;

v_bal NUMBER(7,2);

v_min_bal v_bal%TYPE := 15;


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Data Types--Composite

Composite

RecordsComposite data types

RECORD

Group of related data items stored as fields

TABLE

Holds an array

NESTED TABLE VARRAY


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%ROWTYPE Attribute

Declare a record based on a collection of columns

Example:

DELARE

emp_record emp%ROWTYPE;


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Data TypesSQL Cursors

Implicit

opens an area of memory in which SQL is parsed

and executed

Implicit cursors attributes

SQL%ROWCOUNT

SQL%FOUND

SQL%NOTFOUND

SQL%ISOPEN


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Implicit Cursor

Example:

VARIABLE rows_deleted VARCHAR2(30)

DECLARE

v_empid emp.empid%TYPE := 176;

BEGINDELETE FROM emp

WHERE empid = v_empid;

:rows_deleted := (SQL%ROWCOUNT || rows deleted );

END;

/

PRINT rows_deleted


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Explicit Cursor ExampleDECLARE

------------------ MAIN PL/SQL VARIABLES --------------

V_PS_UU_RPT_LDGR PS_UU_RPT_LDGR%ROWTYPE;V_ERROR_CODE ps_uu_rpt_ldgr_error.UU_ERR_CODE := SQLCODE;

V_ERROR_MSG ps_uu_rpt_ldgr_error.UU_ERR_MSG := SQLERRM;

V_BLOCK_NAME ps_uu_rpt_ldgr_error.UU_BLOCK_NAME := 'PERIOD 0 BLOCK INSERT INTOps_uu_rpt_ldgr_tmp_1';

/* CURSOR TO RETRIEVE DATA TO POPULATE THE V_ACCOUNTING_PERIOD */

CURSOR CUR_VAR IS

SELECT ledger

,BUSINESS_UNIT

,FUND_CODE

,DEPTID,PROGRAM_CODE

,PROJECT_ID

,ACCOUNT

,DESCR

,UU_CUST_DESCR

,CLASS_FLD

,uu_deptid_tran

,UU_FIN_PROG_CLAS

,UU_PROG_NME

,FISCAL_YEAR

,ACCOUNTING_PERIOD

,UU_ORIG_BUD_AMT

,UU_RVSD_BUD_AMT

,UU_ENCB_AMT

,UU_ACTL_AMT

FROM ps_uu_rpt_ldgr_new;


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Explicit Cursor Example Continued/* CURSOR TO CREATE THE UU_CM_BUDG, UU_FYTD_BUDG, UU_FY_BUD,

UU_CM_ENC, UU_FYTD_ENC, UU_FY_ENC,UU_CM_ACTL, UU_FYTD_ACTL, UU_FY_ACTL*/

CURSOR CUR_SUM_DATA ISSELECT

--------- BUDGET SUMS ----------- cm budget

SUM (CASEWHEN accounting_period = V_ACCOUNTING_PERIOD

THEN UU_rvsd_BUD_AMTELSE 0 END) uu_cm_budg

-- fytd budget,SUM (CASE

WHEN (accounting_period >= 1 AND accounting_period


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Explicit Cursor Example ContinuedBEGIN

------------------ MAIN SUBPROGRAM ----------------------

/*OPEN CUR_VAR TO POPULATE THE VALUES FORACCOUNTING_PERIOD, FISCAL_YEAR, AND PROGRAM_CODE

MUST DO THIS BEFORE YOU OPEN CUR_SUM_DATA OTHERWISE

YOU WILL NOT HAVE THE VARIABLE VALUES IN PL/SQL TO

RUN THE NEXT CURSOR */

IF CUR_VAR%ISOPEN THEN

CLOSE CUR_VAR;

END IF;

OPEN CUR_VAR;

LOOP

FETCH CUR_VARINTO v_PS_UU_RPT_LDGR .ledger

, v_PS_UU_RPT_LDGR .BUSINESS_UNIT, v_PS_UU_RPT_LDGR .FUND_CODE

, v_PS_UU_RPT_LDGR .DEPTID

, v_PS_UU_RPT_LDGR .PROGRAM_CODE

, v_PS_UU_RPT_LDGR .PROJECT_ID

, v_PS_UU_RPT_LDGR .ACCOUNT

, v_PS_UU_RPT_LDGR .DESCR

, v_PS_UU_RPT_LDGR .UU_CUST_DESCR

, v_PS_UU_RPT_LDGR .CLASS_FLD, v_PS_UU_RPT_LDGR .uu_deptid_tran

, v_PS_UU_RPT_LDGR .UU_FIN_PROG_CLAS

, v_PS_UU_RPT_LDGR .UU_PROG_NME

, v_PS_UU_RPT_LDGR .FISCAL_YEAR

, v_PS_UU_RPT_LDGR .ACCOUNTING_PERIOD

, v_PS_UU_RPT_LDGR .UU_ORIG_BUD_AMT

, v_PS_UU_RPT_LDGR .UU_RVSD_BUD_AMT

, v_PS_UU_RPT_LDGR .UU_ENCB_AMT

, v_PS_UU_RPT_LDGR .UU_ACTL_AMT;

EXIT WHEN CUR_VAR%NOTFOUND;


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Explicit Cursor Example Continued/*OPEN CUR_SUM_DATA WHICH RUNS THE SQL CACHES DATA

AND FETCH THE CACHED DATA OR THE RESULTS FROM

THE SQL INTO THE VARIABLES*/

IF CUR_SUM_DATA%ISOPEN THEN

CLOSE CUR_SUM_DATA;

END IF;

OPEN CUR_SUM_DATA;

LOOP

v_counter := v_counter +1;

FETCH CUR_SUM_DATA

INTOv_PS_UU_RPT_LDGR .UU_CM_BUDG

, v_PS_UU_RPT_LDGR .uu_fytd_budg

, v_PS_UU_RPT_LDGR .uu_fy_budg

, v_PS_UU_RPT_LDGR .uu_ptd_budg

, v_PS_UU_RPT_LDGR .uu_cm_enc

, v_PS_UU_RPT_LDGR .uu_fytd_enc

, v_PS_UU_RPT_LDGR .uu_ptd_enc

, v_PS_UU_RPT_LDGR .uu_cm_actl

, v_PS_UU_RPT_LDGR .uu_fytd_actl

, v_PS_UU_RPT_LDGR .uu_ptd_actl;

EXIT WHEN CUR_SUM_DATA%NOTFOUND;


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Explicit Cursor Example Continued/*INSERT NEW DATA INTO THE TABLE */

INSERT INTO ps_uu_rpt_ldgr_fnl

(ledger,BUSINESS_UNIT

,FUND_CODE

,DEPTID

,PROGRAM_CODE

. )

VALUES

(v_PS_UU_RPT_LDGR .ledger

, v_PS_UU_RPT_LDGR .BUSINESS_UNIT

, v_PS_UU_RPT_LDGR ._FUND_CODE

, v_PS_UU_RPT_LDGR .DEPTID, v_PS_UU_RPT_LDGR .PROGRAM_CODE

.);IF mod(c_CUR_OTHER_VALUES%ROWCOUNT, 1000)=0

THEN

COMMIT;

END IF;

END LOOP;

END LOOP;

COMMIT;

IF c_CUR_SUM_DATA%ISOPEN THENCLOSE c_CUR_SUM_DATA;

END IF;

IF c_CUR_OTHER_VALUES%ISOPEN THEN

CLOSE c_CUR_OTHER_VALUES;

END IF;


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ExceptionsExample

EXCEPTIONWHEN CURSOR_ALREADY_OPEN

THEN

CLOSE c_CUR_SUM_DATA;


WHEN OTHERS

THEN

IF V_ERROR_CODE > 0

THEN

ROLLBACK;INSERT INTO ps_uu_rpt_ldgr_error(UU_BLOCK_NAME

,UU_ERR_CODE

,UU_ERR_MSG

,UU_DATE)

VALUES (V_BLOCK_NAME

,V_ERROR_CODE

,V_ERROR_MSG

,SYSDATE);END IF;

CLOSE c_CUR_SUM_DATA;


END;

/


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Conditional Logic

IF-THEN-END IF

IF-THEN-ELSE-END IF

IF-THEN-ELSIF-END IF


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Conditional Logic ExampleExample

IF-THEN-END IFIF v_ename = SMITH THEN

v_job := SALES;

v_deptno := 100;

END IF:

IF-THEN-ELSE-END IF

IF v_ename = CLARK THEN

v_job := ADVERTISING;

ELSE

v_job := CLERK;

END IF;

IF-THEN-ELSIF-END IF

IF v_deptno= 80 THEN

v_bonus := 1000;ELSIF v_depton= 90 THEN

v_bonus :=1200;

ELSE

v_bonus :=1100;


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Case Expressions

Choose the result from a list of items

The result the CASE expression uses a selector

Each selector is followed by one or more WHEN

clauses


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Case Expressions Example

Example

DECLARE

v_score student.score%TYPE;

v_grade CHAR(1);

BEGINv_grade :=

CASE

WHEN v_score = 90 THEN A

WHEN v_score = 80 THEN B

WHEN v_score = 70 THEN C

WHEN v_score = 60 THEN D

WHEN v_score


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Loops

Simplest form BASIC LOOPExample

DECLARE

v_country_id location.country_id%TYPE := WA;

v_location_id location.location_id%TYPE;

v_city location.city%TYPE := SEATTLE;

v_counter NUMBER(2) := 1;BEGIN

SELECT MAX(location_id) INTO v_location_id

FROM location

WHERE country_id = v_country_id;

LOOP

INSERT INTO location(location_id, city, country_id)

VALUES((v_location_id + v_counter), v_city, v_country_id);

v_counter := v_counter + 1;EXIT WHEN v_counter > 3;

END LOOP;

END;

/


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While Loop

Pre-test for the condition and execute while a

condition is TRUE

Post-test for the condition having the WHILE

LOOP until the condition tests for FALSE


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While Loop Example

DECLARE

v_country_id location.country_id%TYPE := WA;

v_location_id location.location_id%TYPE;

v_city location.city%TYPE := SEATTLE;

v_counter NUMBER(2) := 1;

BEGIN

SELECT MAX(location_id) INTO v_location_id

FROM location

WHERE country_id = v_country_id;

WHILE v_counter


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ForLoop

FOR LOOP has a control statement before the

LOOP keyword to determine the number of

iterations

FOR LOOPS are used when the number ofiterations is known prior to processing

Great to use in cursors because the FOR LOOP will

automatically OPEN and FETCH


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ForLoop Example

DECLARE

CURSOR sal_cursor IS

SELECT e.deptno, empno, last_name, salFROM emp e, dept d

WHERE

d.deptno = e.deptno

AND d.deptno = 60;FOR UPDATE OF sal NOWAIT;

BEGIN

FOR emp_record in sal_cursor

LOOPIF emp_record.sal < 6000 THEN

UPDATE emp

SET sal = emp_record.sal * 1.10

WHERE CURRENT OF sal_cursor;END IF;

END LOOP;

END;

/


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ExecutingPL/SQL

Invoke PL/SQL anonymous blocks straight from

SQL*PLUS

Run PL/SQL anonymous blocks by embedding the

inside other programs Stored procedure or function you can call it in the

following ways:

SQL*PLUS or iSQL*Plus

Oracle Development tools (Oracle Forms Developer) Another procedure


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ExecutingPL/SQL Example

Anonymous [email protected]

From SQL*PlusEXECUTE execution_one

Stored Procedure

execution_one; From AnotherProcedure

CREATE OR REPLACE PROCEDURE emp_leave

(p_id IN emp.emp_id%TYPE)

IS

BEGIN

DELETE FROM emp

WHERE emp_id = p_id;

log_execution;

END

leave_emp;


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PL/SQL Tips

Naming Conventions V_ variables

P_ parameters

C_ constants CU_ cursors

Assignment Statement

:= Comparison Operators

=

Termination Statement

; PL/SQL is not Case Sensitive

Note: Only Conditional Statements in WHERE Clause are Case Sensitive

WHEN OTHERS List Last or it Will not Process any other Exceptions


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Summary

Powerful language native to the Oracle Server

Move your programs to any host environment

OS

or platform that supports Oracle server.

Grow in your database regardless of the front-end

development platform chosen

PL/SQL can be written Object Oriented with the use

of packages


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Summary Continued

Language able to handle

Conditional logic

Iterative control

Cursors Exception handling

LOB data types

Dynamic variable

Easy maintenance Improved data security and integrity

Performance, and code clarity

2004 presentation 600

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