12/2/13 Creating Interactive APEX Reports Over OLAP Cubes www.oracle.com/webfolder/technetwork/tutorials/obe/db/12c/r1/olap/olap_apex/usingapex4olap.htm?cid=4425&ssid=108537019043697 1/35 Creating Interactive APEX Reports Over OLAP Cubes Purpose In this tutorial, you use Oracle Application Express (APEX) to create an interactive sales analysis report that runs against OLAP data. You learn how to query and create analytic reports of OLAP cubes, including both stored and calculated measures. You also learn how to apply query techniques that leverage unique characteristics of OLAP cubes. NOTE: This tutorial requires either Oracle Database 11.2 or 12.1. Time to Complete: Approximately 60 minutes Topics This tutorial covers the following topics: Overview Scenario Prerequisites Import and Install a Predefined Workspace Create an Application Create an Interactive Sales Analysis Report Format the Interactive Report Add Drilldown Capabilities and Run the Report Add a Report Reset Button More Information Viewing Screenshots Place the cursor over this icon to load and view all the screenshots for this tutorial. (Caution: Because this action loads all screenshots simultaneously, response time may be slow depending on your Internet connection.) Note: Alternatively, you can place the cursor over each individual icon in the following steps to load and view only the screenshot associated with that step. Overview What is APEX? APEX is a Web-based application development and deployment tool integrated with Oracle Database. Using only a Web browser, you can quickly create a reliable, secure, and scalable Web application that can be instantly deployed to thousands of users. APEX combines the ease of use and productivity of a personal database with the availability and scalability of an enterprise database. APEX wizards and built-in features simplify the building of Web applications. You can quickly assemble database-driven applications with little or no programming, in a short span of time. How Do SQL Tools Like APEX Access Oracle OLAP Cubes? The data in an Oracle OLAP cube is made directly accessible to SQL by a set of relational views. These views represent an OLAP cube as a star schema with the following characteristics: - A cube view plays the role of a fact table. - Dimension views and hierarchy views play the role of dimension tables.
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12/2/13 Creating Interactive APEX Reports Over OLAP Cubes
In this tutorial, you use Oracle Application Express (APEX) to create an interactive sales analysis report that runs against OLAP data.
You learn how to query and create analytic reports of OLAP cubes, including both stored and calculated measures. You also learn howto apply query techniques that leverage unique characteristics of OLAP cubes.
NOTE: This tutorial requires either Oracle Database 11.2 or 12.1.
Time to Complete:
Approximately 60 minutes
Topics
This tutorial covers the following topics:
Overview
Scenario
Prerequisites
Import and Install a Predefined Workspace
Create an Application
Create an Interactive Sales Analysis Report
Format the Interactive Report
Add Drilldown Capabilities and Run the Report
Add a Report Reset Button
More Information
Viewing Screenshots
Place the cursor over this icon to load and view all the screenshots for this tutorial. (Caution: Because this action loads all
screenshots simultaneously, response time may be slow depending on your Internet connection.)
Note: Alternatively, you can place the cursor over each individual icon in the following steps to load and view only the screenshotassociated with that step.
Overview
What is APEX?
APEX is a Web-based application development and deployment tool integrated with Oracle Database. Using only a Web browser, youcan quickly create a reliable, secure, and scalable Web application that can be instantly deployed to thousands of users.
APEX combines the ease of use and productivity of a personal database with the availability and scalability of an enterprise database.APEX wizards and built-in features simplify the building of Web applications. You can quickly assemble database-driven applicationswith little or no programming, in a short span of time.
How Do SQL Tools Like APEX Access Oracle OLAP Cubes?
The data in an Oracle OLAP cube is made directly accessible to SQL by a set of relational views. These views represent an OLAP cubeas a star schema with the following characteristics:
- A cube view plays the role of a fact table.
- Dimension views and hierarchy views play the role of dimension tables.
12/2/13 Creating Interactive APEX Reports Over OLAP Cubes
The star design exposed by OLAP cubes is very similar to traditional table-based star models. The dimension views form aconstellation around one or more cube views. However, there are two key differences:
- Fact tables in a star schema store detail data (called leaves), while the cube views reveal many summary levels.
- Calculations in a cube are simply exposed as columns in the cube view, and the computation for the equations occursin the OLAP engine.
These differences impact the way you query data. With star queries, you aggregate the data by combining aggregation functions (suchas sum) and the GROUP BY clause.
With OLAP queries, you simply select the data you want (either stored or calculated) as a column. Selecting aggregate data is easilyaccomplished using conditions in the "where" clause. Typically, no aggregation function is necessary since the data has already beensummarized by the cube. This enables a single, parameterized cube query to be used to return data from any summary level. Forexample, no changes to the query are required to select sales revenue by month, quarter or year. This greatly simplifies the ability to"drill anywhere".
For the vast majority of cube-based queries, there are four basic steps:
1. Select measures and dimension attributes.2. Join the cube and dimension views.3. Apply measure and dimension attribute conditions.4. Use “All” filters to leverage summaries for excluded dimension columns.
Combining APEX and Oracle OLAP
APEX provides a flexible environment for the creation of applications on top of any Oracle Database data source. Therefore, you cancreate compelling, interactive, exploratory reports using APEX against OLAP data using the OLAP cube views.
Since OLAP cube views encapsulate the business rules for your data, it is very simple to select and explore the analytic information thatyou need. When combining OLAP cube views and APEX, you can deliver interactive analysis dashboards very easily.
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Scenario
In this tutorial, you create an interactive, analytic report of OLAP data by performing the following five tasks:
1. Import and install a predefined APEX Workspace. The workspace includes an APEX developer with access to theolaptrain sample schema.
2. Create an application that will contain the report.
12/2/13 Creating Interactive APEX Reports Over OLAP Cubes
3. Create an interactive report that includes highly stylized output.
4. Add formatting to the report.
5. Leverage query parameters to enable data exploration using “drilling” across the dimensions in the report.
Note: OLAP supports the style of drilldown used in this tutorial with any type of hierarchy: level-based, parent-child, skip-level, ragged,and so on.
When you are done, you will have a formatted, interactive sales analysis report that enables users to explore data by drilling down onproducts, times, and geographies. The resulting report will look like the following:
Using this report, users:
Can drill down on Geography, Product, and Time to any level of detail
May want to follow the “Product Alert” column when drilling down, since this column indicates that Sales have dropped compared tolast year for at least one of the children of the current product
For example, in the preceding report, Computers’ Sales in 2008 for Africa have improved by 22.4% compared to last year, but there is anALERT. Drilling down on Computers will show that there is a problem with sales within the department.
Note: The OLAP data for this tutorial was created using steps found in the Building OLAP Cubes tutorial. For information about the OLAPdata model, and for step-by-step instructions on how to create OLAP cubes, go to More Information.
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Prerequisites
Before you perform this tutorial, you should:
1. Install Oracle Database 11.2 or 12.1 with the OLAP Option.
2. Download and install the OLAPTRAIN sample schema and the OLAP data model that is based on the sampleschema. Use the instructions found in Installing the Oracle OLAP Sample Schema.
3. Have access to Oracle Application Express, version 3.1.2 or higher. You can Download and install OracleApplication Express from OTN.
Notes:
On Windows, Application Express runs in shared server mode - even if the database is configured in dedicated
An Oracle configuration parameter needs to set in order to access OLAP cubes when Oracle Database isconfigured in shared server mode. Otherwise, an error will be generated referencing the inability to load an OLAPAPI sharable library.
Listed below is an example of how to update the configuration parameter when the database is started using anspfile:
a. Login into sqlplus as sysdba. For example:
b.Execute the following SQL command:
SQL> alter system set "_xsolapi_load_at_process_start"=ALWAYS scope=spfile;
c. Then, stop and restart the database. For example:
SQL> shutdown immediate
. . .
SQL> startup
d.Exit SQL Plus.
4. Save and extract OLAP11g-APEX.zip to a location on the computer that contains APEX. This archive contains two
files: SALESTRACK_WORKSPACE.sql and apex-olap.sql. The first file is a predefined APEX workspace thatprovides access to the OLAP data. The second file contains a predefined OLAP cube query that you use as part ofthe definition of your interactive report.
5. Have basic knowledge of Oracle Application Express. For more information on APEX, see the following OBEtutorials on Oracle Application Express.
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Import and Install a Predefined Workspace
In this topic, you log into APEX as the administrator. You then import and install a predefined workspace that contains an APEXdeveloper. You will also create an APEX schema that provides access to the sample OLAPTRAIN schema.
Follow these steps to create the interactive report:
1. Start your web browser and navigate to the Application Express login page for administrators using the following URLformat:
Result: the workspace import and installation is complete:
10.Click the Logout link to log out of the APEX Administration tool.
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Create an Application
In this topic, you log into APEX as a developer and access the predefined workspace. WIthin the workspace, you define an applicationfor your interactive report.
Follow these steps:
1. Start your web browser and navigate to the Application Express login page using the following URL format:
http://<hostame>:<port#>/apex
Note: The port number is defined by the APEX administrator when APEX is installed.
For example:
http://localhost:8080/apex
2. Log in using the following details:
- Workspace: SALESTRACK
- Username: olaptrain
- Password: oracle
12/2/13 Creating Interactive APEX Reports Over OLAP Cubes
Next, you perform two primary tasks to develop the interactive report:
Create three Hidden Items that are used later as part of a parameterized query. The parameters you define will be used for settingup dimension “drilling” in a later topic.
For example, a hidden item named P1_PRODUCT will be used as a parameter for drilling down on the Product dimension in thesales query as follows:
p.parent = nvl(:P1_PRODUCT, 'ALL_PRODUCTS')
Note: This condition selects the children of the product represented by the parameter (and selects “ALL_PRODUCTS” ifP1_PRODUCT is null).
You will create similar hidden items for the Time and Geography dimensions.
Create an interactive report region that:
- Incorporates a predefined OLAP cube SQL query that drives the report
- Shows sales performance by region, product, and time.
Perform the following steps:
1. In the Application Builder window, which is shown at the end of the previous topic, click the Sales Analysis icon.
Result: You are now in the Page Editor, as shown here.
12/2/13 Creating Interactive APEX Reports Over OLAP Cubes
9. In the Source step, you will use the predefined SQL query that you downloaded earlier (from the Prerequisitessection) as the source for the report region.
Perform the following:
a. Select File > Open File from the browser’s main menu.
b. Open the <download_location>/apex-olap.sql file, that you downloaded previously.
c. Select the query and copy it to the clipboard.
Note: This single SELECT statement, explained in the following image, is used to navigate vast regions of theOLAP cube. Notice that the parameter names match the hidden items you created previously.
12/2/13 Creating Interactive APEX Reports Over OLAP Cubes
8. Scroll through the report to view the formatting.
9. Save the report as the default.
a. Click the Gear icon and then select Save Report from the menu.
b. Name the report Default Report Settings.
c. Click Apply.
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Add Drilldown Capabilities and Run the Report
The next task is to enable drilldown capabilities to the report. When users click a Geography, Product or Time value, the details for theselected item will replace what was selected. For example, clicking CY2009 displays the calendar quarters for that year.
APEX allows you to specify links for columns on the Report Attributes page. In this case, the link will set the relevant dimensionparameter (a.k.a. Hidden Item) to the item the user selected.
Consider the flow for a drilldown on the Time dimension:
User clicks the CY2009 link.
The logic behind the link specifies that the parameter P1_TIME is set to the selected value.
The query is re-executed, whereby the condition:
t.parent = nvl(:P1_TIME, 'ALL_YEARS')
Selects all time values whose parent is ‘CY2009.’ This is the equivalent to selecting the children of ‘CY2009.’
Result: A drilldown has been executed.
Perform the following steps to add drilldown capabilities to the report:
1. Return to the page editor by clicking the Edit Page 1 link at the bottom of the report page.
2. Go to the Report Attributes page by clicking the Interactive Report link in the Regions pane.
12/2/13 Creating Interactive APEX Reports Over OLAP Cubes
3. Add a drilldown link to Geography by performing the following:
a. Click the Edit icon for Geography.
b. Click the Link button above the Column Definition page.
c. In the Column Link window, click the [Geography] link to create the Link Text, and then enter 1 in the Pagetext box (that is, the current page number is “1”).
d. Then, use the flashlight tools to select the name value pairs as shown here:
12/2/13 Creating Interactive APEX Reports Over OLAP Cubes
- You set the “link” dimension to the current member. This value, as described earlier, will cause thedrilldown on Geography.
- You also set parameters for the Product and Time dimensions as well. By setting these values to the parentcolumn, you are effectively preserving the state of the report (the children of a parent produces the current setof members). This allows browser operations like bookmarking to re-create the report in its drilldown state;these parameters appear in the URL.
e. When you are done, the Column Link window should look like this:
Click Apply Changes.
4. Add a drilldown link to Product:
a. Click the Edit icon for Product.
12/2/13 Creating Interactive APEX Reports Over OLAP Cubes
7. Once again, click Run at the top of the Page Definition window. The report should look like this:
8. For Africa, click the Computers link for CY2008 (as shown below). This is the row that had excellent percentgrowth in sales, but showed an Alert in the following data.
12/2/13 Creating Interactive APEX Reports Over OLAP Cubes
The resulting report shows the Computer division products that contain underlying alerts:
9. Experiment with the interactive report by clicking on any of the interactive links. With every drill, the OLAP engine re-calculates the data and returns the query results great speed.
This one query enables the user to navigate vast regions of the OLAP cube, providing an interactive, ad-hoc queryand analysis reporting environment.
10. When you are done with the report, click Logout.
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Add a Report Reset Button
It is often useful to add a reset button to the report. This allows you to reset the report to its original state.
To add a reset button:
1. Click the Application 101 link at the bottom of the login page (as shown below) to return to the Application Builder
12/2/13 Creating Interactive APEX Reports Over OLAP Cubes