The Power of theOracle APEX Repository

Patrick Wolf, Sphinx IT ConsultingDOAG SIG – APEX for Advanced, 31-May-2007

About Sphinx IT Consulting• Founded 1993• Creates mission-critical individual software• Consulting for Databases & Java Middleware • Specialized in Oracle• More information at http://www.sphinx.eu/

About Patrick Wolf• 13 years of Oracle experience with SQL, PL/SQL and

Oracle Forms• Solution Architect at Sphinx IT Consulting• Run an APEX Blog – http://inside-apex.blogspot.com• Author of the ApexLib Frameworks – http://apexlib.

sourceforge.net/• Author of the Oracle APEX Builder Plugins• Contact mail is patrick.wolf@sphinx.at

Agenda• The Oracle APEX Repository• Part 1 - The APEX Dictionary Views

– Simple queries– Automatic documentation creation– Monitoring APEX Applikations– Create generic code using the repository

• Part 2 – Directly manipulating the APEX Repository– Do mass updates in the Repository– Create new Page Items, ...

• Q&A

The Oracle APEX Repository• Oracle APEX stores all meta-data of an application in a

repostiory in the database

– Schema FLOWS_xxx (eg.: FLOWS_030000)

– Table prefixed with WWV_FLOW_*

– This tables are not public.

• Starting with version 2.2 there is a view access layer.

• Prefix of the views is APEX_*

• Since 3.0 there is an user interface for simple queries. Can be found at Utilities/APEX Dictionary

The APEX Dictionary Views• Returns a „readable“ form of the internal APEX Repository

tables– Hide the generic/old data model– Lookups for Foreign-Keys– Translate interne Enumerations into English– Contains statistic counters – eg. Number of child elements– Checks access privileges (you only see your applications)

• Connected as schema user: All applications of the workspaces where the schema is assigned to.

• Connected as SYS, SYSTEM, FLOWS_xxx: All applications

• Other users: nothing• The Views are public and can therefore be used in APEX

applications or in external scripts.

The APEX Dictionary Views

Select Tree view

The APEX Dictionary Views

Hierarchical representation

The APEX Dictionary Views

The APEX Dictionary Views

Documentation of each column

The APEX Dictionary Views

Don’t forget thequote!

To execute press„Go“ button at thebeginning of thepage

The APEX Dictionary Views

The APEX Dictionary Views• Divided into 3 areas

– Application-Meta-Data• APEX_APPLICATION*

– Monitoring data about the application• APEX_WORKSPACE_ACCESS_LOG• APEX_WORKSPACE_ACTIVITY_LOG• APEX_WORKSPACE_LOG_SUMMARY*• APEX_WORKSPACE_CLICKS• APEX_WORKSPACE_SESSIONS

– Workspace-Meta-Data• The reminding APEX_WORKSPACE* views. For

example APEX_WORKSPACE_APEX_USERS, ...

The APEX Dictionary Views• What are usage examples for the views?• A few examples

– Quality checks a coding styleguides, …– Dynamic generation of Site-Maps– Automatic documentation of the application– Automatic monitoring of the application– Some nice page view charts– For the creating of generic code– And so on...

Quality check 1• Don’t use the „xxx Label with Help“ Label Template for

Page Items.

SELECT APPLICATION_NAME , PAGE_ID , ITEM_NAME , DISPLAY_AS , ITEM_LABEL_TEMPLATE FROM APEX_APPLICATION_PAGE_ITEMS WHERE ITEM_LABEL_TEMPLATE LIKE '%Label with Help' AND DISPLAY_AS <> 'Hidden' ORDER BY APPLICATION_NAME , PAGE_ID , ITEM_NAME;

Quality check 2• Are all labels left aligned?

SELECT APPLICATION_NAME , PAGE_ID , ITEM_NAME , DISPLAY_AS , LABEL_ALIGNMENT FROM APEX_APPLICATION_PAGE_ITEMS WHERE LABEL_ALIGNMENT <> 'Left' AND DISPLAY_AS <> 'Hidden' ORDER BY APPLICATION_NAME , PAGE_ID , ITEM_NAME;

Quality check 3• Has a help text been entered for all Page Items where the

„xxx Label with Help“ Template has been used?

SELECT APPLICATION_NAME , PAGE_ID , ITEM_NAME , DISPLAY_AS FROM APEX_APPLICATION_PAGE_ITEMS WHERE ITEM_LABEL_TEMPLATE LIKE '%Label with Help' AND DISPLAY_AS <> 'Hidden' AND ITEM_HELP_TEXT IS NULL ORDER BY APPLICATION_NAME , PAGE_ID , ITEM_NAME;

Dynamic Site-Maps• Create a automatically generated Site-Map for your

application.• Tag relevant pages with $SITEMAP$ in the page

comment.SELECT PAGE_ID , PAGE_TITLE , PAGE_GROUP FROM APEX_APPLICATION_PAGES WHERE APPLICATION_ID = :APP_ID AND INSTR(PAGE_COMMENT, '$SITEMAP$') > 0 ORDER BY PAGE_TITLE;

• Create SQL Report with above SQL statement.• For column „PAGE_TITLE“, change Link Text to

#PAGE_TITLE# and Page to #PAGE_ID#• Set column „PAGE_ID“ to „Hidden“.• Page Groups could be used to get a hierarchical

representation in a tree view…

Automatic Documentation• Wouldn’t it be nice to have a diagram of the Page Flow of

an application? Which page calls which page…• Like JDeveloper, where there is a Page Flow editor for JSF

applications, but which has be manually mantained…• Not like other development environments where the

necessary data is stored somewhere in XML files or in Java/… code, we have all the necessary data accessible with simple SQL queries!

• With the help of Graphviz an open source tool, the graphical diagram generation is quite easy.

Page Flow Generator• Analyses the meta-data of an application, like Pages,

Branches, Buttons, Links- in Report Columns, HTML Regions and SQL Statements.

• Creates a dependency model in the memory and• creates for each Page Group (to keep them small) it’s own

diagram.• The complicated part was the Graphviz syntax.• The Page Flow Generator is part of the ApexLib

Frameworks.

Monitoring APEX Applications 1• Wouldn’t it be cool if the administrator automatically gets

notified if an error occurs in the application?• APEX provides the view APEX_WORKSPACE_ACTIVITY_LOG

and the column ERROR_MESSAGE for such a purpose.• A DBMS_JOB can be used to check it periodically.• See blog entry http://oraclequirks.blogspot

.com/2007/05/simple-pager-for-apex-30.html• And with http://inside-apex.blogspot

.com/2007/05/sending-sms-to-mobile-phone.html you can set it up to send a SMS.

Monitoring APEX Applications 2• How to detect hackers trying to break into your

application?• The view APEX_WORKSPACE_ACCESS_LOG logs each login

attempt with the following data– Timestamp– Usernamen– IP address– Result – Successful/Failed

Monitoring APEX Applications 3• How can you detect if the response time of you

application decreases?• The view APEX_WORKSPACE_ACTIVITY_LOG logs each

page access and the column ELAPSED_TIME tells you how long APEX needed to generate the page.

• Combined with historical data and the number of users currently accessing the system you can estimate a trend of your response time.

• The view can also be used to analyze the navigation behavior of your users. Also see column THINK_TIME for the time the user waited till opened another page.

• Or create a query which returns the pages which are never called.

• And so on…

Create Generic Code 1• Ever had the problem that you had a page where the

Page Items are very similar and number VALUE1, VALUE2, … and where you had to create the same validation for all of them? Boring job, isn’t it?

• There is also a way to do it with less effort!BEGIN FOR rITEM IN ( SELECT ITEM_NAME FROM APEX_APPLICATION_PAGE_ITEMS WHERE APPLICATION_ID = :APP_ID AND PAGE_ID = :PAGE_ID AND ITEM_NAME LIKE 'P'||:PAGE_ID||'_VALUE%' ) LOOP IF V(rITEM.ITEM_NAME) IS NOT NULL THEN APEX_Util.set_session_state ( p_name => rITEM.ITEM_NAME , p_value => 1 ); END IF; END IF;END;

Create Generic Code 2• Ever needed a cascading/hierarchical LOV?• Have you implemented Carl Backstom’s (http://carlback.

blogspot.com/) AJAX example for each LOV?• Isn’t all required information available in the meta-data of

the Page Item? The WHERE clause of the LOV contains all dependencies!

• Why don’t we use it and stop duplicating code and information about the dependencies?

• That’s what the Open Source ApexLib Framework (http://apexlib.sourceforge.net/) does!

• Short demonstration of the framework.

APEX Dictionary Views - Conclusio

• Are a powerful tool which you can use to enhance your application of your development process.

• There a lot of possible scenarios where you can use them, you just have to come up with some good ideas.

• Use the APEX Dictionary View Browser to get used to them!

• Available since Oracle APEX Version 2.2.

Manipulating the APEX Repository• Ever had the requirement to make a bulk update in your

application? For example to change the Label Template to “without Help” for all Page Items.

• Or create with your own code Page Items, … Your own wizard.

• Oracle APEX doesn’t offer an official tool to fulfill above requirements.

• But if already all the meta-data of the application are in the database…

• But the result of doing a direct update on the repository tables can really be surprising. The application isn’t accessible anymore in the builder!

• So how do it the right way?

Manipulating the APEX Repository

BACKUP, BACKUP, BACKUP!!!

• Make a backup/export of the FLOWS_XXX schema before you do any manipulation of the repository tables! At least do an export of your application!

• Use the following tips at your own risk !

Manipulating the APEX Repository• The manipulation is down connected as FLOWS_xxx (eg.

FLOWS_030000).• The tables are prefixed with WWV_FLOW*• The best way to identify the tables and columns is to have

a look at the APEX Dictionary Views.• Create a reference record. Eg. With the new Label

Template• Set APEX context with

WWV_Flow_API.set_security_group_id• What is the Security Group ID?

– Is equal to the Workspace ID and can be get with Apex_Util.get_security_group_id(`Workspacename`)

Manipulating the APEX Repository

DECLARE vSecurityGroupId NUMBER;BEGIN vSecurityGroupId := Apex_Util.find_security_group_id ( p_workspace => 'SPHINX_SXSD' ); IF vSecurityGroupId = 0 THEN RAISE_APPLICATION_ERROR ( -20111 , 'Workspace not found! Do not issue updates' ); END IF; -- WWV_Flow_Api.set_security_group_id(vSecurityGroupId); WWV_Flow.g_user := 'PWOLF';END;

• Example to initialize the APEX context.

Manipulating the APEX Repository• Example which sets the Label Template from „Optional

Label with Help“ to „Optional Label“ on all Page Items on page 4.

UPDATE WWV_FLOW_STEP_ITEMS SET ITEM_FIELD_TEMPLATE = 6.61528317798547E18 WHERE FLOW_ID = 106 AND FLOW_STEP_ID = 4 AND ITEM_FIELD_TEMPLATE = 7.22798225629576E18;

FLOW_ID equals to Application Id

FLOW_STEP_ID equal to Page Id

Manipulating the APEX Repository• What can I do if my application isn’t accessible after an

update anymore?– Check the SECURITY_GROUP_ID in WWV_FLOWS.– If it’s 0, initialize the APEX context and set the

SECURITY_GROUP_ID in WWV_FLOWS again.

UPDATE WWV_FLOWS SET SECURITY_GROUP_ID = NULL WHERE FLOW_ID = 106;

NULL is used by intention!

Manipulating the APEX Repository• How can we create new Page Items, …?• APEX provides the public(!) but undocumented package

WWV_Flow_Api• Can be called from a package in the application schema

or from FLOWS_XXX.• There are a lot of examples, just view the export file of an

application.• WWV_Flow_Api.g_id_offset is used during import to get

unique IDs -> not required in our case.• The next free ID is returned by WWV_Flow_Id.next_val.

Manipulating the APEX Repository• The following session initialization steps are required if

you are executing the code outside of an APEX session. For example when you are connected to FLOWS_XXX.

• Initialize APEX context as done for an update + execute the following code.

BEGIN SELECT VALUE INTO WWV_Flow_Api.g_nls_numeric_chars FROM NLS_SESSION_PARAMETERS WHERE PARAMETER = 'NLS_NUMERIC_CHARACTERS' ; EXECUTE IMMEDIATE 'ALTER SESSION SET NLS_NUMERIC_CHARACTERS=''.,'''; -- WWV_FLOW.g_browser_language := 'en'; WWV_Flow_Api.g_id_offset := 0;END;

Manipulating the APEX Repository• Just create a new Page Item with the following example

code.DECLARE vPageItemId NUMBER;BEGIN WWV_Flow_Api.set_version ( WWV_Flow_Api.g_compatable_from_version ); WWV_Flow.g_flow_id := 100; -- Application Id -- vPageItemId := WWV_Flow_Id.next_val; -- WWV_Flow_Api.create_page_item ( p_id => vPageItemId , p_flow_id => WWV_Flow.g_flow_id , p_flow_step_id => 4 , p_name => 'P4_TESTIT' ... );END;

Manipulating the APEX Repository - Conclusio

• BACKUP, BACKUP, BACKUP!!!• For updates, do a direct update on the tables.• Always create a Reference record.• Do inserts with the WWV_Flow_Api package.• Application export file has good example.

Any questions?