These are a set of questions and answers to help you prepare for interviews for roles involving Oracle Business Intelligence (OBIEE). I recommend that you do not simply try to memorize these questions and answers, but use them as a guide or to help you determine what you need to work on more to improve your knowledge and skills.
——————–
IMPORTANT DISCLAIMER: I cannot guarantee the correctness of any of these answers, and anyone using them should verify their correctness using other sources.
——————–
Q1. The business users mention that a particular report is not returning the correct results. How would you go about identifying if there is an issue and what the issue is?
A1. The answers to this question could vary widely because there are a few options of what you may do first, second, etc.
I would first determine why the users think the results are wrong. Compare their expected results with the report results to determine what data values are being dropped or added. This may require a detailed-data to detailed-data comparison.
Next, I would determine when the “wrong results” started up. Based on that, I would check if anything changed within the timeframe that could have affected this. If anything changed, you or another team member can investigate the details of the change.
Next, I would try to determine if the data is correct by comparing the source system data with the data from the report source, such as the data warehouse. If the data in the data warehouse is correct, then it would indicate that something might be wrong with the report. if the data in the data warehouse is not correct, then that indicates there might be a problem with the ETL process or logic. Check filters, aggregation logic, selection steps, and more in the area that needs further examination (whether the analysis or the ETL).
If necessary, I would get the SQL generated by OBI for the analysis via the session logs, and run that SQL directly on the database, removing or adding to the SQL as necessary to investigate various scenarios with the data.
This could be one of the first things that you do, but if I had not found the issue as yet because everything looks good so far, clear the cache and see if that resolves the issue.
Q2. Can you create an analysis from multiple subject areas? And if yes, how would you go about doing it?
A2. Yes, you can create an analysis/report using multiple OBIEE Subject Areas. First create an analysis as normal, by selecting the first subject area and then selecting the desired columns, and performing any desired calculations, formatting, or other manipulations on those columns. Then, from the Subject Areas pane, click the Add Subject Area icon (cube with a plus sign) and select the second subject area, from which you will then select the desired columns. You will need to union or join the data from these subject areas.
Q3. What is the purpose of the OBIEE RPD?
A3. The OBIEE RPD (Repository) is a metadata layer between the data sources (such as a relational databases or files) and the OBIEE front-end that is accessed through a web browser, which includes the Dashboard & Analysis Editor used by report developers or analyst, along with the published dashboards & analyses (reports) that the users see. The RPD allows developers to create a business representation of the data, and create a business friendly view of the model, including renaming of columns to business friendly vocabulary, creating new data elements (such as metrics) from calculations and manipulations, defining hierarchies useful to business processes, and more. This allows report developers and power users and analysts to be able to drag and drop columns to create analyses (reports).
Q4. Name and describe the various layers of the OBIEE Repository (RPD).
A4. There are 3 layers in the OBIEE Repository (RPD). The Physical layer, the Business Model and Mapping layer, and the Presentation layer.
The Physical layer is where you define the data sources, including connection details, that you will use to source data for your OBIEE environment. In this layer, you will import or define your table metadata, create aliases (a recommended practice), define the joins between tables (typically using the alias tables), create opaque views (“select” tables), and set caching options.
The Business Model and Mapping layer, referred to as BMM or logical layer, is where you will define the business model of the data from the physical model. The business model is geared toward providing specific information needed for your specific business scenario. The business model typically simplifies the representation from the physical model to form a more business friendly view of the data.
The BMM layer is where you will rename objects to more business friendly names, create business metrics from the data, create hierarchies useful for various business processes, define logical tables and columns and joins,
The Presentation layer is where you define the view seen by users in the front end reporting and analysis tools, such as, OBIEE Answers. This layer allows you to structure/organize/label all data elements from the BMM layer into an easily understood, business friendly model – further simplifying the BMM model and making it more business friendly – that facilitates drag and drop usage for end users.
Q5. What are some of the types of analysis views that are available in OBIEE?
A5. Some of the types of analysis views available in OBIEE are: table (straight table), pivot table, graph, funnel, gauge, trellis, filters, column selector, view selector, narrative, ticker, and static text.
Q6. What are some of the graph types available in OBIEE?
A6. Some of the types of graphs available in OBIEE are: bar (vertical, horizontal, and stacked); line; line-bar; area, pie; pareto; scatter; bubble; radar
Q7. Describe the steps for creating an analysis?
A7. Understand the requirement. Confirm that the data elements are available. From the menu, New -> Analysis. Select the appropriate subject area. Find the columns that you need. Bring them into the report. Perform calculations and other data manipulations as necessary on one or more columns. Rename and format columns as necessary. Create the data views that provide the best representation of the data and/or that meets users’ requirements. Verify the results by testing various scenarios – such as different time frames, different data elements, testing with prompt selections, and all the elements that need to validated to confirm you are meeting the users’ requirements.
Q8. What are the different types of variables in OBIEE?
A8. There are two types of variables available in OBIEE and they are: (1) repository variables and (2) session variables.
Repository variables can have only a single value at any point in time, and are system-wide (repository-wide), hence the name Repository variable.
Repository variables can be used in ways similar to how you would use a constant or literal value in expressions in the RPD or in an analysis.
Repository variables have two sub-types: (i) static and (ii) dynamic
A static repository variable has a fixed value that is defined in the variable definition in the RPD (OBIEE repository), and stays that way until changed by a developer/administrator.
A dynamic repository variable (as the name implies) changes (is refreshed) based on the results returned from Initialization Block SQL queries that run on a defined schedule.
Session variables can contain more than one value and are created and assigned a value “for each session” when each user logs on, hence the name session variable. Each user’s session variable may be different depending on the logic used to generate the value for the variable.
Session variables have two sub-types: (i) system and (ii) non-system
System session variables are special variables used by OBIEE for specific “system” purposes and the same variable names cannot be used for other variables. An often used system session variable is “USER” that gets set to the value of the current logged in user’s ID.
Non-system session variables are custom defined variables, typically set by an initialization block. An often used non-system session variable scenario is one in which the variable values for each user is used in data filters to implement dynamic data-level that changes for each user.
Q9. What is an Initialization Block?
A9. An Initialization Block (Init Block) is an object defined with a “block” of SQL that is executed to “initialize” a variable specified in the Initialization Block’s definition. Init Blocks are used to initialize dynamic repository variables, system session variables, and non-system session variables.
Q10. How do you refresh the cache in OBIEE?
A10. One of the quickest ways is to run the “call SAPurgeAllCache();” statement in the Administration -> Issue SQL window.
You can get more details here … https://businessintelligence.technology/2013/10/11/how-to-clear-the-bi-server-cache-using-command-line-script-or-via-the-issue-sql-page/
Q11. How do you create navigation from one report to another based on the user clicking on a data value in the first report?
A11. You would create an Action Link on the navigate-from column (in the Interaction tab of the column properties) in your first report. In the Action Link, set the appropriate action, such as “Navigate to BI Content”, to specify the second report that you need to navigate to.
Q12. Describe the steps involved in building an OBIEE repository (RPD).
A12. The steps involved in building an OBIEE RPD can be separated into 3 sets of steps: (1) Build the Physical Layer, (2) Build the Business Model and Mapping (BMM) Layer, (3) Build the Presentation Layer
(1) Build the Physical Layer
- Create the repository
- Import metadata
- Create aliases
- Create physical keys and joins between the appropriate tables
(2) Build the BMM Layer with objects from the Physical Layer
- Review and adjust (if necessary) the Logical Joins
- Rename logical columns
- Add logical table sources (as necessary)
- Create derived columns
- Create metrics
- Remove unneeded logical objects
- Create hierarchies
(3) Build the Presentation Layer
- Create a Subject Area
- Create or drag over Presentation tables
- Create Presentation columns
- Rename Presentation columns
- Rearrange/organize Presentation columns into a user friendly view
Then, upload and test the RPD using analyses created in Answers.
Q13. Why is it recommended that you use Alias Tables in OBIEE?
A13. Alias tables are defined in the Physical Layer of the RPD. They are used to create a version of a physical table with a different user determined name, therefore allowing for the re-use of tables for multiple joins/data sets within the physical layer. Another benefit of aliases is if there is a change to the physical table, in some cases those changes can be isolated by, for example, mapping the new columns in the physical table to existing columns in the alias, and preventing the need for other changes to the data model and in the various layers of the RPD.
Q14. How would you go about resolving performance issues with a specific report in OBIEE?
A14. Run the report through the dashboard. Capture the SQL associated with the report. Run that SQL directly on the database (using a tool such as SQL Developer or Toad) to see if it is performing poorly there also. If it is, then we can deduct that the issue is on the database side or the report needs to be changed enough to make it generate a different SQL. If it runs fine directly on the database, then the issue is somewhere else along the stack.
Taking the first scenario – runs poorly directly on database – review the SQL or run an explain plan on the SQL and determine what changes can be made to improve it. This may involve adding indexes to tables on columns used in joins and in filtering criteria; reducing records in tables as appropriate before joining; removing unnecessary joins; changing the data model of the tables used, such as creating star schemas or creating aggregate tables. If necessary, work with a DBA to get help.
Taking the second scenario – runs fine directly on the database – review the analysis to determine what type of views are being used and determine by elimination if any of them are causing an issue; play around by removing columns and re-running to determine if any specific columns or calculations are causing an issue; check the logs to see if there any relevant messages to your scenario and adjust configuration parameters accordingly and re-run to determine if any effect.
Q15. What would you do if you are unable to figure out an OBIEE issue?
A15. There could be several reasonable answers to this question. A few good responses include … ask a co-worker, use a search engine (google/bing/etc) to try to find a solution, clear the cache, restart all processes at an appropriate time, search Oracle’s support site, create a Service Request (SR) with Oracle Support, post a description of your issue to relevant online groups/communities and ask for help, (when appropriate) meet with others in your environment to try to determine what has changed that you are unaware of that may have caused the issue. There could be many other valid responses.
Q16. What are some recent OBI dashboards that you have created? -OR- Please describe some recent OBI projects that you have worked on.
A16. There are many ways to answer these open ended questions, but a few things I would suggest are:
- describe the project
- describe your role in the project
- (where applicable) briefly describe your development process/methodology
- (where applicable) describe how you worked with the business users to determine or review the requirements, perform training, perform validation, resolve issues, etc.
- describe how you sourced the data (source systems)
- describe how you designed and/or developed the solution (include some details without being too long, such as explaining what areas you designed/developed – data model, and/or RPD and reports, or just RPD, or just reports, etc.)
- describe any challenges you ran into, and how you/team resolved
- describe how you may have assisted others or worked with others or trained others
- as you describe all the above, make sure it demonstrates what you brought to the project
- And then finally, share the end result – for example, share if the users loved the solution and the kind of feedback that made you know that, what it helped them to do, if it saved them a lot of time, if this led to increased application usage, etc.
Q17. How do you move/migrate an OBIEE solution from one environment to another, such as, from your DEV to TST environment?
A17. The answer to this question could vary a bit, but may include things such as:
- Use the same scripts from DEV to create any new database objects in TST.
- Use Archive/Unarchive to move OBIEE catalog objects by Archiving the objects from DEV and unarchiving them into TST -OR- Use the Catalog Manager tool to move the catalog objects from DEV to TST.
- Take the RPD from DEV and upload and activate it in TST -OR- merge the approved RPD changes from DEV into the TST RPD
- Apply the appropriate security permissions to the objects in TST.
- If there was a new ETL process involved in the solution, ensure that the ETL objects are also migrated to the ETL TST environment.
- Restart the TST environment servers
- Validate that everything is good, and if not, resolve by migrating anything that’s missing
Q18. How do you implement data-level security in OBIEE?
A18. First, determine how each user’s data-level access will be identified, that is, determine what table will house the data that specifies the access that each user has to the data. For example, if the data is to be secured by department, the table would contains records of each user and the department(s) that they have access to.
Then, create an Initialization Block that selects the departments for each user and assigns them to a session variable (DEPT_VAR).
Next, identify the appropriate roles for which the data-level security rules need to be applied, and set the filters (table.department = ‘DEPT_VAR’) on the appropriate data sets using the above variable.
Test the solution.
You can get more details here … https://businessintelligence.technology/2017/08/10/implementing-data-level-security-in-oracle-bi-obiee/
Q19. What is an Agent? And when would you use it?
A19. An Agent (formerly called iBot in OBIEE 10g) is a scheduled or conditionally triggered process that runs and executes a specified report (analysis) based on hitting the schedule or condition. Once the Agent runs, the analysis results can be sent to a user via email (attached or embedded), or to the dashboards in the form of an alert that the user will see when he/she accesses the dashboards. So, agents can be used to provide analyses’ results to specified users on some specified schedule or condition without any manual intervention. Another use of Agents is, the can be used to seed the OBI cache over night after the nightly ETL has completed, to make the reports faster for the first set of users in the morning.
Q20. What are some functions that you have used in OBIEE Answers to manipulate column data?
A20. There could be wide range of answers here, but some of the commonly used functions include:
- Aggregate functions, such as, MIN, MAX, SUM, AVG, COUNT, TopN
- String functions, such as, CONCAT, LEFT, RIGHT, REPLACE, SUBSTRING, TRIMBOTH, UPPER
- Mathematical functions, such as, ROUND, FLOOR, TRUNCATE, ABS
- Datetime functions, such as, CURRENT_DATE, TimeStampAdd, TimeStampDiff, Year, Month, Now
- Conversion functions, such as, CAST, IfNULL, CASE
However, your response should include the functions you have used, and be able to explain how you used them.
—————
Thanks for reading. More sets will be available in the future. Good luck!
