View the companion webinar at: http://embt.co/1xcLFjJ If you’ve ever wanted to code or understand more about PL/SQL code, this 2-part series is for you. Join Oracle ACE Director, Dan Hotka and Solutions Consultant Director, Scott Walz as they present and demo the fundamentals of PL/SQL and much more. Watch the webinar to learn about: + PL/SQL variable types and naming convention + How to code PL-SQL + When to use IF-THEN-ELSE or CASE + Profiling and debugging PL/SQL

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PL/SQL Tips & Techniques
Scott Walz | Embarcadero Director of Software Consultants
Dan Hotka |Author & Instructor |Oracle Ace Director

2. EMBARCADERO TECHNOLOGIES
PL/SQL Tips and Techniques
• Rapid SQL
– PL/SQL Templates
• Read my blogs
– PL/SQL Debugging
• Prior Webinar
– PL/SQL Profiling
• Read my blogs
• PL/SQL Tips
– Oracle Overview
– Compiler Options
• Includes some useful performance
Tips for Functions

3. EMBARCADERO TECHNOLOGIES
Oracle Architecture
Default
Result
Cache
(11g)
Oracle SGA
Keep
(optional)
PGA
Dedicated
User
Processes
Listener
Shared Pool
TNSNAMES.ORA
LISTENER.ORA
Tablespaces
Database Files
Database Files
Database Files
Buffer Pool
nK
(Optional)
Recycle
(Optional)
Library
Cache
Dictionary
Cache
Shared
SQL
SQL
Source
Exe Plan
Call
Stack
UGA
Sess
Data
Cursor
Area
Sort
Area
Client
Result
Cache
(11g)
PL/SQL
Engine
SQL Engine
SQL
Statement
External Files
UTL File
External Tables
OCI/JDBC
URL

4. EMBARCADERO TECHNOLOGIES
Oracle Architecture

5. EMBARCADERO TECHNOLOGIES
PL/SQL Overview
• Procedure
– Does processing
– Returns a code that the work was successful or not
– May or may not be passed values
– May or may not return values
• Functions
– Similar to Procedure EXCEPT it does return a value!

6. EMBARCADERO TECHNOLOGIES
PL/SQL Overview
• Packages
– Grouping related procedures and functions
– Can share cursors/work areas
– Code inheritance
– When one module is accessed…entire package is loaded
into Oracle
• Database Triggers
– Assigned to tables
– Executes before or after a DML to the table

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Rapid SQL Templates
• IF-THEN-ELSE
– Can nest 250+ Deep
– ELSE is optional
– ELSIF is indeed misspelled!
Ctrl+ Space bar

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Rapid SQL Templates
IF_ENDIF IF_ELSIF

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Rapid SQL Templates

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Rapid SQL Templates
• Case
– Alternative to IF-THEN-ELSE
– Can nest 250+ Deep
– ELSE is optional
Case + Ctrl+ Space bar

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Rapid SQL Templates
CASE

12. EMBARCADERO TECHNOLOGIES
Rapid SQL Templates

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PL/SQL Profiling
• Profiler
– How long each routine took to execute
– How long each line of code took to execute
– RapidSQL has a nice interface
• Easy to use
• Highlights performance issues
– Dan will demonstrate how it works…

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Rapid SQL Profiler

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PL/SQL Debugging
• Debugger:
– Oracle symbolic debugger
– Changing variable content on the fly
– Setting code breakpoints
– Stepping through code dependencies
Demo

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Stored Programs Syntax
• Procedures
– Optional parameters
• NOCOPY makes reference
to original parameter
• Useful when passing
collections
– AUTHID is Definer unless
specified!
– Autonomous Transaction
• Allows for DML no matter
how current transaction
ends
– Accessible by (list)
• Oracle12 New Feature
• Only executable by this list
of routines
Create [or replace] Procedure
[ (parameter IN OUT IN OUT …) [NOCOPY] ]
[AUTHID {DEFINER | CURRENT_USER } ]
[ACCESSIBLE BY (<list>)]
{IS | AS}
[PRAGMA AUTONOMOUS_TRANSACTION;]
[ local variables]
BEGIN
<logic flow code>
[EXCEPTION]
<exception code processing.
END [procedure name];

17. EMBARCADERO TECHNOLOGIES
Stored Programs Syntax
• Functions
– Optional parameters
– Allows for Parallel DML
– DETERMINISTIC
• Allows for the previous
result to be used rather
than rerunning the
function when using
the same parameters
– Accessible by (list)
• Oracle12 New Feature
• Only executable by this
list of routines
Create [or replace] Function
[ (parameter …) ]
RETURN <datatype>
[AUTHID {DEFINER | CURRENT_USER } ]
[PARALLEL_ENABLE]
[ACCESSIBLE BY (<list>)]
[DETERMINISTIC]
[RESULT_CACHE] - 11g
{IS | AS}
[PRAGMA AUTONOMOUS_TRANSACTION;]
[ local variables]
BEGIN
<logic flow code>
Must have a RETURN clause
[EXCEPTION]
<exception code processing.
END [function name];

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Stored Programs Syntax
Functions called from SQL CANNOT:
• Commit or rollback
• Update the database
• Update same table as DML SQL

19. EMBARCADERO TECHNOLOGIES
Oracle 11g Query Result Cache
• IF same function called with same in_vars
• SQL with /*+ RESULT_CACHE */ hint
• Function with RESULT CACHE syntax
– RELIES_ON (table1, table2, …) – optional table DML check
• Depreciated in Oracle11r2
• First result cache returned instead of rerunning the function/SQL!
• Results stored in the SGA (Result Cache Memory)
• Any session running the function/SQL can benefit!
– * Enterprise Edition of Oracle
• Good for any table that is queried more than it is updated
– Result Cache is flushed with an update

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11g Query Result Cache
• Query Result Cache Sizing and
Monitoring
– Sizing via Init.Ora settings:
• RESULT_CACHE_MAX_SIZE
– 0 disables it
– Size in bytes in increments of 32K [num
G | M | K ]
– Initially defaults to 10% Shared Pool Size
• RESULT_CACHE_MAX_RESULT
– 0 – 100
– Percentage of
RESULT_CACHE_MAX_SIZE single result
can take
– Dynamic performance views:
• V$RESULT_CACHE_STATISTICS
• V$RESULT_CACHE_MEMORY
• V$RESULT_CACHE_OBJECTS
• V$RESULT_CACHE_DEPENDENCY

21. EMBARCADERO TECHNOLOGIES
Oracle 11g Query Result Cache
Be careful out there!
– Make sure the SQL inside the function does not have other
dependencies
• Such as a SYSDATE or some other variable NOT passed in as an in
variable
• Can probably fix about ANY problem by putting the dependencies
as in variables!

22. EMBARCADERO TECHNOLOGIES
New PL/SQL Features
Oracle12 allows for Granting Roles to PL/SQL Programs
– A major problem in the past is a called program accesses a
table…the connected user needed permissions to both the
program and the underlying table
– Oracle12 allows for permissions to be granted to just the
package/procedure/function so the users cannot directly
access the underlying tables!
Oracle Database 12c New Features pg 246-248

23. EMBARCADERO TECHNOLOGIES
Questions
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24. EMBARCADERO TECHNOLOGIES
Thank you for attending!
Connect with us Online
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m/index.php/article/articles-database
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