Tuesday, November 26, 2013

OBIEE Interview Questions


Define pipeline. Did you use it in your projects?
o Yes, pipelines are the stages in a particular transaction. Assessment, finance etc.
How do you create filter on repository?
o Where condition on content tab.
How do you work in a multi user environment? What are the steps?
o Create a shared directory on the network for Multi-user Development (MUD).
o Open the rpd to use in MUD. From Tools->Options, setup the MUD directory to point to the above directory.
o Define projects within the rpd to allow multiple users to develop within their subject area or Facts.
o Save and move the rpd to the shared directory setup in point 1.
o When users work in the MUD mode, they open the admin tool and start with
o MUD ->Checkout to checkout the project they need to work on (not use the File open as you would usually do).
o After completely the development, user checkin the changes back to the network and merge the changes.
Where are passwords for user id? Ldap, external table authentication stored respectively?
o passwords for user id are in Siebel analytics server repository Ldap authentication in Ldap server external database in a table in external database
Can you bypass siebel analytics server security ?if so how?
o yes you can by-pass by setting authententication type in NQSCONFIG file in the security section as:authentication_type=bypass_nqs.instanceconfig.xml and nqsconfig.ini are the 2 places
Where can you add new groups and set permissions?
o you can add groups by going to manage>security>add new groups> You can give permissions to a group for query limitation and filter conditions.
what are the things you can do in the BMM layer?
o Aggrigation navigation,level base matrics,time series wizard,create new logical column,comlex join.
what is Ragged hierarchy? and how do u manage it
o Ragged Hierarchy is one of the different kinds of hierarchy.
o A hierarchy in which each level has a consistent meaning, but the branches have inconsistent depths because at least one member attribute in a branch level is unpopulated. A ragged hierarchy can represent a geographic hierarchy in which the meaning of each level such as city or country is used consistently, but the depth of the hierarchy varies.
o For example, a geographic hierarchy that has Continent, Country, Province/State, and City levels defined. One branch has North America as the Continent, United States as the Country, California as the Province or State, and San Francisco as the City. However, the hierarchy becomes ragged when one member does not have an entry at all of the levels. For example, another branch has Europe as the Continent, Greece as the Country, and Athens as the City, but has no entry for the Province or State level because this level is not applicable to Greece for the business model in this example. In this example, the Greece and United States branches descend to different depths, creating a ragged hierarchy.
What is the difference between Single Logical Table Source and Multiple Logical Table Sources?
o If a logical table in BMM layer has only one Table as the source table then it is Single LTS.
o If the logical table in BMM layer has more than one table as the sources to it then it is called Multiple LTS.
o Ex: Usually Fact table has Multiple LTS’, for which sources will be coming from different Physical tables.
Can you let me know how many aggregate tables you have in your project? On what basis have you created them?
o As per resume justification document
How do you bring/relate the aggregate tables into the Siebel analytics Logical layer?
o One way of bringing the Aggregate Tables into the BMM layer is by bringing them as Logical Table sources for the corresponding Fact table.
o This is done by dragging and dropping the aggregate table into the corresponding fact table. After doing that establish the column mappings and the set the aggregation levels.
How do you know which report is hitting which table, either the fact table or the aggregate table?
o After running the report, go to Administration tab and go to click on Manage Sessions. There you can find the queries that are run and in the View Log option in the Session Management you can find which report is hitting which table.
Suppose I have report which is running for about 3 minutes typically. What is the first step you take to improve the performance of the query?
o Find the sql query of the report in Admin->manage Session-> run the sql query on toad ->read the explain plan output ->modify the SQL based on the explain plan output
Suppose you have a report which has the option of running on aggregate table. How does the tool know to hit the Aggregate table and for that what the steps you follow to configure them?
o Explain the process of Aggregate navigation
Have you heard of Implicit Facts? If, so what are they?
o An implicit fact column is a column that will be added to a query when it contains columns from two or more dimension tables and no measures. You will not see the column in the results. It is used to specify a default join path between dimension tables when there are several possible alternatives.
o For example, there might be many star schemas in the database that have the Campaign dimension and the Customer dimension, such as the following stars:
Campaign History star. Stores customers targeted in campaign.
Campaign Response star. Stores customer responses to a campaign.
Order star. Stores customers who placed orders as a result of a campaign.
In this example, because Campaign and Customer information might appear in many segmentation catalogs, users selecting to count customers from the targeted campaigns catalog would be expecting to count customers that have been targeted in specific campaigns.
To make sure that the join relationship between Customers and Campaigns is through the campaign history fact table, a campaign history implicit fact needs to be specified in Campaign History segmentation catalog. The following guidelines should be followed in creating
segmentation catalogs:
Each segmentation catalog should be created so that all columns come from only one physical star.
Because the Marketing module user interface has special features that allow users to specify their aggregations, level-based measures typically should not be exposed to segmentation users in a segmentation catalog.
What is aggregate navigation? How do you configure the Aggregate tables in Siebel Analytics?
o Aggregate tables store precomputed results, which are measures that have been aggregated (typically summed) over a set of dimensional attributes. Using aggregate tables is a very popular technique for speeding up query response times in decision support systems.
o If you are writing SQL queries or using a tool that only understands what physical tables exist (and not their meaning), taking advantage of aggregate tables and putting them to good use becomes more difficult as the number of aggregate tables increases. The aggregate navigation capability of the Siebel Analytics Server, however, allows queries to use the information stored in aggregate tables automatically, without query authors or query tools having to specify aggregate tables in their queries. The Siebel Analytics Server allows you to concentrate on asking the right business question; the server decides which tables provide the fastest answers.
(Assume you are in BMM layer) We have 4 dimension tables, in that, 2 tables need to have hierarchy, then in such a case is it mandatory to create hierarchies for all the dimension tables?
o No, its not mandatory to define hierarchies to other Dimension tables.
Can you have multiple data sources in Siebel Analytics?
o Yes.
How do you deal with case statement and expressions in siebel analytics?
o use expression builder to create case when…then.. end statement
Do you know about Initialization Blocks? Can you give me an example where you used them?
o Init blocks are used for instantiating a session when a user logs in.
o To create dynamic variable you have to create IB to write sql statement.
what is query repository tool?
o It is utility of Seibel/OBIEE Admin tool
o allows you to examine the repository metadata tool
o for example: search for objects based on name,type.
o Examine relationship between metadata objects like which column in the presentation layer maps to which table in physical layer
what is JDK and why do we need it?
o Java Development Kit (JDK), A software package that contains the minimal set of tools needed to write, compile, debug, and run Java applets.
Oracle doesn’t recommend Opaque Views because of performance considerations, so why/when do we use them?
o an opaque view is a physical layer table that consists of select statement. an opaque view should be used only if there is no other solution.
Can you migrate the presentation layer to a different server.
o No we have to migrate the whole web & rpd files
How do you identify what are the dimension tables and how do you decide them during the Business/Data modeling?
o Dimension tables contain descriptions that data analysts use as they query the database. For example, the Store table contains store names and addresses; the Product table contains product packaging information; and the Period table contains month, quarter, and year values. Every table contains a primary key that consists of one or more columns; each row in a table is uniquely identified by its primary-key value or values
Why do we have multiple LTS in BMM layer?What is the purpose?
o to improve the performance and query response time.
what is the full form of rpd?
o there is no full form for rpd as such, it is just a repository file (Rapidfile Database)
how do i disable cache for only 2 particular tables?
o in the physical layer, right click on the table there we will have the option which says cacheable
How do you split a table in the rpd given the condition. ( the condition given was Broker and customer in the same table) Split Broker and customer.
o we need to make an alias table in the physical layer.
What type of protocol did you use in SAS?
o TCP/IP
Did you create any new logical column in BMM layer, how?
o Yes. We can create new logical column in BMM layer.
o Example: Right click on fact table -new lgical column-give name for new logical column like Total cost.
o Now in fact table source,we have one option column mapping, in that we can do all calculation for that new column.
Can you use physical join in BMM layer?
o yes we can use physical join in BMM layer.when there is SCD type 2 we need complex join in BMM layer.
Can you use outer join in BMM layer?
o yes we can.When we are doing complex join in BMM layer ,there is one option type,outer join is there.
What are other ways of improving summary query reports other than Aggregate Navigation and Cache Management
Indexes
Join algorithm
Mat/view query rewrite
Web proper report design its optimal by making sure that it is not getting any addition column or rows
What is level-base matrics?
o Leval-base matrics means, having a measure pinned at a certain level of the dimension. For Example, if you have a measure called Dollars, you can create a Level Based Measure called Yearly Dollars which (you guessed it) is Dollars for a Year. This measure will always return the value for the year even if you drill down to a lower level like quarter, month… etc. To create a level based measure, create a new logical column based on the original measure (like Dollars in the example above). Drag and drop the new logical column to the appropriate level in the Dimension hierarchy (in the above example you will drag and drop it to Year in Time Dim
o A LBM is a metric that is defined for a specific level or intersection of levels.
o Monthly Total Sales or Quarterly Sales are the examples.
o You can compare monthly sales with quarterly sales. You can compare customer orders this quarter to orders this year
What is logging level?Where can you set logging levels?
o You can enable logging level for individual users; you cannot configure a logging level for a group.
o Set the logging level based on the amount of logging you want to do. In normal operations, logging is generally disabled (the logging level is set to 0). If you decide to enable logging, choose a logging
o level of 1 or 2. These two levels are designed for use by Siebel Analytics Server administrators.
o Set Logging Level
1. In the Administration Tool, select Manage > Security.
2. The Security Manager dialog box appears.
3. Double-click the user.s user ID.
4. The User dialog box appears.
5. Set the logging level by clicking the Up or Down arrows next to the Logging Level field
What is variable in sieble?
o You can use variables in a repository to streamline administrative tasks and modify metadata content dynamically to adjust to a chainging data environment.The Administration Tool includes a Variable Manager for defining variables
What is system variable and non system variable?
o System variables
o System variables are session variables that the Siebel Analytics Server and Siebel Analytics Web use for specific purposes. System variables have reserved names, which cannot be used for other kinds of variables (such as static or dynamic repository variables, or for nonsystem session variables).
o When using these variables in the Web,preface their names with NQ_SESSION. For example, to filter a column on the value of the variable LOGLEVEL set the filter to the Variable NQ_SESSION.LOGLEVEL.
o Nonsystem variables.
o A common use for nonsystem session variables is setting user filters. For example, you could define a nonsystem variable called SalesRegion that would be initialized to the name of the user.s sales region. You could then set a security filter for all members of a group that would allow them to see only data pertinent to their region.
o When using these variables in the Web, preface their names with NQ_SESSION. For example, to filter a column on the value of the variable SalesRegion set the filter to the Variable NQ_SESSION.SalesRegion.
What are different types of variables? Explain each.
o There are two classes of variables:
1. Repository variables
2. Session variables.
Repository variables.
A repository variable has a single value at any point in time. There are two types of repository variables:
static : This value persists, and does not change until a Siebel Analytics Server administrator decides to change it.
dynamic:The values are refreshed by data returned from queries. When defining a dynamic repository variable, you will create an initialization block or use a preexisting one that contains a SQL query. You will also set up a schedule that the Siebel Analytics Server will follow to execute the query and periodically refresh the value of the variable.
Session Variables
Session variables are created and assigned a value when each user logs on. There are two types of session variables:
1.system
2.nonsystem.
What are the cache management? Name all of them and their uses. For Event polling table do u need the table in your physical layer?
o Monitoring and managing the cashe is cache management.There are three ways to do that.
o Disable caching for the system.(INI NQ config file), Cashe persistence time for specified physical tables and Setting event polling table.
o Disable caching for the system.(INI NQ config file :
You can disable caching for the whole system by setting the ENABLE parameter to NO in the NQSConfig.INI file and restarting the Siebel Analytics Server. Disabling caching stops all new cache entries and stops any new queries from using the existing cache. Disabling caching allows you to enable it at a later time without losing any entries already stored in the cache.
o Cashe persistence time for specified physical tables :
You can specify a cachable attribute for each physical table; that is, if queries involving the specified table can be added to the cache to answer future queries. To enable caching for a particular physical table, select the table in the Physical layer of the Administration Tool and select the option Make table cachable in the General tab of the Physical Table properties dialog box. You can also use the Cache Persistence Time settings to specify how long the entries for this table should persist in the query cache. This is useful for OLTP data sources and other data sources that are updated frequently, potentially down to every few seconds.
o Setting event polling table :
Siebel Analytics Server event polling tables store information about updates in the underlying databases. An application (such as an application that loads data into a data mart) could be configured to add rows to an event polling table each time a database table is updated. The Analytics server polls this table at set intervals and invalidates any cache entries corresponding to the updated tables.
o For event polling table ,It is a standalone table and doesn’t require to be joined with other tables in the physical layer
What is Authentication? How many types of authentication.
o Authentication is the process by which a system verifies, through the use of a user ID and password, that a user has the necessary permissions and authorizations to log in and access data. The Siebel Analytics Server authenticates each connection request it receives.
Operaing system autentication
External table authentication
Database authentication
LDAP authentication
What is object level security?
o There are two types of object level security: Repository level and Web level
o Repository level : In presention layar we can set Repository level security by giving permission or deny permission to users/groups to see particular table or column.
o web level:thisprovides security for objects stored in the siebel anlytics web catlog,such as
dashboards,dashboards pages,folder,and reportsyou can only view the objects for which you are authorized. For example,a mid level manager may not be granted access to a dashboard containing summary information for an entire department.
What is data level security?
o This controls the type an amount of data that you can see in a report.When multiple users run the same report the results that are returned to each depend on their access rights and roles in the organization.For example a sales vice president sees results for alll regions, while a sales representative for a particular region sees onlu datafor that region.
What is the difference between Data Level Security and Object Level Security?
o Data level security controls the type and amount of data that you can see in a reports.Objectlevel security provides security for objects stored in the siebel analytics web catlog, like dashboards,dashboards pages,folder,and reports.
How do you implement security using External Tables and LDAP?
o Instead of storing user IDs and passwords in a Siebel Analytics Server repository, you can maintain lists of users and their passwords in an external database table and use this table for authentication purposes. The external database table contains user IDs and passwords, and could contain other information, including group membership and display names used for Siebel Analytics Web users. The table could also contain the names of specific database catalogs or schemas to use for each user when querying data
o Instead of storing user IDs and passwords in a Siebel Analytics Server repository, you can have the Siebel Analytics Server pass the user ID and password entered by the user to an LDAP(Lightweight Directory Access Protocol ) server for authentication. The server uses clear text passwords in LDAP authentication. Make sure your LDAP servers are set up to allow this.
If you have 2 fact and you want to do report on one with quarter level and the other with month level how do you do that with just one time dimension?
o Using levelbase matrics.
Did you work on a stand alone Siebel system or was it integrated to other platforms?
o Deploying the Siebel analytics platform without other Siebel applications is called Siebel analytics Stand -Alone .If your deployment includes other siebel Analytics Application it called integrated analytics -You can say Stand-Alone siebel analytics
How to sort columns in rpd and web?
o Sorting on web column, sort in the rpd its sort order column
If you want to create new logical column where will you create (in repository or dashboard) why?
o I will create new logical column in repository.because if it is in repository,you can use for any report.If you create new logical column in dashboard then it is going to affect on those reports ,which are on that dashboard.you can not use that new logical column for other dashboard(or request)
What is complex join, and where it is used?
o we can join dimention table and fact table in BMM layer using complex join.when there is SCD type 2 we have to use complex join in Bmm layer.
If you have dimension table like customer, item, time and fact table like sale and if you want to find out how often a customer comes to store and buys a particular item, what will you do?
o write a query as SELECT customer_name, item_name, sale_date, sum(qty) FROM customer_dim a, item_dim b, time_dim c, sale_fact d WHERE d.cust_key = a.cust_key AND d.item_key = b.item_key AND d.time_key = c.time_key GROUP BY customer_name, item_name, sale_date
You worked on standalone or integrated system?
o Standalone.
If you want to limit the users by the certain region to access only certain data, what would you do?
o using data level security.
o Siebel Analytics Administrator: go to Manage -> Security in left hand pane u will find the user, groups, LDAP server, Hierarchy
What you can do is select the user and right click and go to properties, you will find two tabs named as users and logon, go to user tab and click at permission button in front of user name you have selected as soon as u click at permission you will get a new window with user group permission having three tabs named as general ,query limits and filter and you can specify your condition at filter tab, in which you can select presentation table ,presentation columns ,logical table and logical columns where you can apply the condition according to your requirement for the selected user or groups.
If there are 100 users accessing data, and you want to know the logging details of all the users, where can you find that?
o To set a user.s logging level
1. In the Administration Tool, select Manage > Security.
The Security Manager dialog box appears.
2. Double-click the user.s user ID. The User dialog box appears.
3. Set the logging level by clicking the Up or Down arrows next to the Logging Level field
How do implement event polling table?
o Siebel Analytics Server event polling tables store information about updates in the underlying databases. An application (such as an application that loads data into a data mart) could be configured to add rows to an event polling table each time a database table is updated. The Analytics server polls this table at set intervals and invalidates any cache entries corresponding to the updated tables.
Can you migrate the presentation layer only to different server
o No we can’t do only presentation layer. And ask him for more information and use one of the above answers
o Create a ODBC connection in the different serve and access the layer.
o Copy the Rpd and migrate it to other server.

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