OBIEE Interview Questions and answers for Experienced
Question.1 What is single LTS and multiple LTS?
Answer: The logical table created at the BMM layer can be based on the data from a single physical layer table, when it is called single Logical Table source. When the specific logical layer table is dependent on the columns of different physical layer tables, it is called Multiple LTS. Most of the time we will be dealing with Multiple LTS.
Question.2 If we have 5 different dimension tables and we need to have hierarchies for only one table, is it mandatory to have hierarchies implemented for all the tables?
Answer: No, it is not mandatory to create the hierarchies for all the tables, we can just define hierarchies to those tables that need to have it.[sociallocker]
Question.3 How is the Query repository tool used?
Answer: The Query repository tool gives the option to search and analyse the data from the database according to the name, type and other attributes that are describing the database.
The relationship between the different view layer data and the corresponding the physical layer columns.
Question.4 What are opaque views in database? When is it advisable to create one?
Answer: The opaque views are tables that are created with join or other query data that contain “SELECT” query output. The opaque views make the logical understanding simple for implementation but there are heavy performance constraints. They are only used when there is no other way to get to the final solution.
Question.5 How does the user of Aggregate tables help you in speeding up query responses? How is Siebel Analytics Server advantageous in this aspect?
Answer: The Aggregate tables are the ones that get values initialized in them as and when the related fields in the other tables get updated. This type of automatic updates to frequently used measures help you in speeding up the queries. If there is a column for number of products produced for every month and you often want to have the summation of the number per year and average for every year often for all the queries, the aggregate table created will have the option to give you that value without computations every time. Siebel Analytics server gives the added advantage that the queries need not be aware of the readily available aggregate table names. If this was the case the SQL queries and the entire design might become complex.
Question.6 What is an implicit fact column?
Answer: The implicit fact column is the one that is created due to the join, combinations from the different data or columns from the different tables. There may not be the exact data in form of the column in the result or even in the physical layer of database. These are implied from different data and can just be a temporary layer which help us in getting the required result.
Question.7 How can you map each of the reports across to the different tables that are being accessed?
Answer: The Admin tool has the “Manage Sessions” tab which gives you the access to the logs that are being generated for each session.After the report generation sessions, you can easily view the log to map each requests to the corresponding tables and databases.
Question.8 How can you migrate the presentation layers across to different servers?
Answer: The presentation layer is dependent on the database that is underlying in the each server. Therefore the presentation layer alone cannot be migrated as a stand-alone aspect of the database. What we can do instead is have a ODBC or similar database connection established across from the different servers to the particular main system and then carry over the presentation semantics from the other server with that database oriented changes in the logic layer.
Question.9 How will you impose access limitation to the database according to the region of access?
● The Data level security imposed according to data in certain column can be used to limit access depending on the regions.
● The Siebel Analytics admin tool will give you the control over user access to the different data according to conditions supplied by you.
Question.10 Which is preferable? Creating the new logical column in the repository level or the Dashboard level of view?
Answer: Creation of the logical column on the higher level of dashboard will have effect on the tables only on that view level and not on the other dashboards and other requests. The logical columns created on the repository level will in turn gets its effect on all the other requests and reports from different view levels. So it is always preferable to have the logical column created at the repository level.
Question.11 What are the different deployment cases for the Siebel Analytics server?
Answer: The Siebel Analytics server can be deployed as a stand alone system or can be deployed as an integrated server which interfaces and communicates to the different Analytics server.
Question.12 What are the External table based and LDAP based security?
Answer: The user ID and password need not be stored in the repository of the Siebel Analytics server. The external tables and LDAP offer the other possibilites. The userID and password for user authentication are stored in the external table. The information on different tables and the access information for each user are stored in this external table. The other way is the Lightweight Directory Access Protocol. This is similar to imposing a access limitation to all the different directories and folders thereby having the limitations to the data viewable for the different users.
Question.13 Differentiate Object level security against the Data level security.
● The Object level security is a higher level of security that allows/disallows the access for user to specific table, row or column according to his access level. The Data level security level is about restrictions that are concerned about the different data that are used to generate the report of other view level information.
● The Object level of security are permissions corresponding to the objects in the database (like database reports, dashboards, folders etc) and such permissions are set in the view level, logical level or data level. The Data level security mostly set in the database level and related logic table level.
Question.14 What are the various levels of access authentications?
Answer: There are four levels of authentication that can restrict access to the different tables and databases:
Operating level authentication: This is the overall higher level access restriction to the application. Without this one cannot get access to the application.
Table authentication: The table level authentication is the access permissions set for each physical table.
Database authentication: The Database user and password, corresponding previleges can let someone to access specific db or can just give him only partial access. This authentication is the main thing for the application that coordinates different databases. LDAP authentication.
Question.15 What are the different types of caching?
Answer: The cache management can be done in three different ways:
● Cache disabled: The NQConfig.INI file has the ENABLE parameter that can be set to NO. This disables the cache for the server. After the change the server needs a restart. The disable cache will prevent any queries to use/update cache. This may lead to slower performances, but will be useful in the case of lesser accesses that are being expected. Enabling of the cache will not be concerned about the cache updates and synchronization.
● Caching set for each physical table: The admin tool has the option “Make cache-abble” for the tables. You can click that and go into the general settings. This has the cache persistence in the option. This will make the queries to and fro from the physical table to use the cache. This can also be set according to specific time interval. This will help you in getting a good interactive response on the view layer. Any table that is frequently updated can have this setting on for reasonable amount of time.
● Event Polling data: The event polling data table keeps track of the different updates that are done on the different tables. The application is going to updated this event polling table for each query of update into the physical table. This stand-alone table can get the required frequency statistics for each table to maintain the cache policies as required.
Question.16 What are two main categories of variables overall?
Answer: There are two types of variables, namely the session variables and the repository variables. The session variables are pertaining to each session that is created for every login of a user. They may be System or Non-system variables.
The repository variables are the ones that are specific to a repository/database. The repository variables contain the parameters that are corresponding to different attributes of the respository and queries. They are again classified as static and dynamic variables. The static variables are the ones that are having permanent values through out. The administrator can change it whenever needed. The dynamic variables are the ones that have values that are corresponding to the SQL queries and data fetches. The dynamic variables can take up values depending on the scheduled updates that are started by the administrator. They can also take up values fue to the SQL queries that have been recently executed from the user side. Initialization blocks run at specific time or triggered according to specific condition.
Question.17 What are the different types of session variables that you are aware of?
Answer: There are 2 different types of variables that we deal with in the Siebel architecture:
● System variables: The system variables are the ones that are used by the analytics server and web to manage and coordinate the sessions and related data. Such names cannot be used for non system variables or other repository variables. You can try naming such variables with a prefix to identify their nature and content. This will make it easier for classification within each session.
● Non-System variables- The non system variables are always used to have user-defined aspects of data stored at a specific place. If you have a data called “numberOfPersons” in a specific data from the user space, you can then use this to classify the entire database according to the numberOfPersons etc.
When using the variables from the Analytics Webserver, you can just prefix the variable name with NQ_SESSION.(Varaiblename) to narrow down the scope to the present session.
Question.18 How can you use the Siebel variables to cope up with dynamic data environments?
Answer: The Siebel variable are the storage parameters that we can link within the metadata and other configuration parameters in the Siebel. With the help of the variable manager, all the confguration parameters can be loaded into the specific variable depending upon the different environments we are trying to have. This can help us in making the administrative tasks simpler.
Question.19 How do you set the logging level as an administrator in Siebel?
Answer: The Siebel Analytics Sever has the “Security” configuration in the Manage section of the admin tool. This dialog box has the settings for each user id. Click the specific user id. You can then get the logging level selection inside this settings. You can choose the appropriate level and save the changes. [/sociallocker]
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