Monday, July 8, 2019

Oracle DAC Interview Questions

Q1) Illustrate on the architecture of DAC
DAC comprises of the DAC client and the DAC server. It is important to note they must realign themselves with Information Integration Service and Information Repository.
Q2) How to export and import DAC architecture?
DAC export and import are primarily used for backup or repository metadata. The logical system and runtime objects can facilitate essential and commodity.
Q3) Can we facilitate the running of multiple plans related to accomplishments at the same time in DAC?
The answer is yes. However, it can be facilitated only when the accomplishment process is not loading into the same table.
Q4) How can you execute the SQL script with the help of DAC? If the answer is yes, then illustrate how it can be achieved?
The SQL script can be executed with the help of the DAC server. However, it can be implemented only at the task level. It can be accomplished by selecting the SQL file in the process of execution.
Q5) What do you mean by an authentication file?
The file of authentication usually authenticates the database in which the repository lies. On the other hand, if you opt for creating an authentication file, then you have the liberty to specify the particular table and password for a specified set of the database.
Q6) What do you mean by Table, Task Actions and Index in DAC?
The table refers to override the default behavior for assessing and truncating various tables that are being assigned to a particular type of database. On the other hand, Task Action refers to the fact that one can add multiple types of new functionalities related to the behavior of the tasks. It comprises of failure action, success action, and failure restart. Moreover, index action refers to override the practice of creating and dropping indexes.
Q7) How can you differentiate between homogeneous and heterogeneous plans related to accomplishments in DAC?
A different plan related to accomplishments refers to the fact that it can extract data from one or more chances of source systems that are dissimilar. For instance, a business organization can have a score of Siebel 7.8 in one location. On the other hand, an example of Oracle EBS 11 can be in another position. One can also opt for staggering the timing of data extraction when the professional is using this type of plans related to accomplishments.  
On the other side, homogenous plans related to accomplishments also pulls database systems from various instances of the system that has originated from the same source. A suitable example, in this case, can be in the form of the fact that a business can have Oracle EBS 11 in one place and time zone and another portion of EBS 11 in another position and time zone. In the cases mentioned above, data extraction timing can be altered so that the business needs of an organization can be met. 
Q8) Define how DAC can determine the tasks that are needed for a particular type of subject area.
It is vital to note that a subject area can be defined by assigning a fact table. Moreover, a subject area can also be specified by assigning a set of fact tables. When a subject area is adequately defined, DAC also performs the below-mentioned procedures to assess the essential tasks related to data warehousing.
  • DAC is involved with the identification of the source tables for the tasks that are being identified in processes previous to the one that was called for to carry out data warehousing. DAC also adds tables to the places of a subject.
  • With the help of DAC, one can also eliminate an assignment from a particular subject area by using add or remove command. These commands are located on the tasks tab. It is also found in the places of a subject tab. However, when someone deletes a particular assignment, it gets removed only from the area of a subject until and unless you refigure the data patterns that are located in the places of matter.
  • It is interesting to note that the tasks that are automatically assigned by DAC are specified to a subject area. It can be done so by selecting the Inactive checkbox. It is located in the places of a subject tab.
  • Moreover, DAC also performs this process in a recursive manner. It is also important to note that until all necessary assignments are completed, they are usually added to the tab that is located in the subject area. A task is generally added to the area of the subject only once. DAC also expands or lowers the number of functions that are based on the specifications related to configuration. This technique or process can be resource intensive as DAC installs a wide variety of data objects into the system before the memory of the server is exhausted.
  • DAC also identifies the table of dimensions that are involved with the facts and usually adds these data tables to the places of a subject.
  • It can also correctly locate the related data tables such as aggregates that are always associated with the schedules of dimensions. You can also opt to add them to the subject area of proportion. 
Q9) Illustrate on the various types of DAC Repository Objects that are usually held in the containers related to source system
There exist multiple kinds of DAC repository objects that are essential in order to make sure that the data warehousing tasks are being accomplished in a proper manner. The following are the various objects related to the DAC Repository.
1. Tables: They are also known by physical tables in DAC.
2. Assignments: They are also popularly referred to as tasks and are usually known as a unit of work loading tables.
3. Indexes: Indexes are also known as the physical DAC indexes which facilitates the value assignment of data.
4. Data structure Tables: Data structure tables play a pivotal role in the proper measurement of various types of data. They are also referred to as the indexes related to DAC.
5. Group of Tasks: The classification of assignments can be collected to run as a particular collective group.
6. Plans related to the execution process: A data alteration technique that is usually defined on the places of a subject. These sites of an issue are the core places that need to be altered at various frequencies in a particular frame of mind.
7. Time schedules or time-frequency: It is associated with the correct assessment of the running of the execution process.
Q10) Illustrate the process of how DAC usually keeps track of the time of refresh for the source tables and target tables.
The dates related to refresh are usually tracked for the tables. The tables can be a primary source or can also be a prime target. These primary and source target tables are typically based on the completed trial of particular plans related to accomplishments. The DAC can even run the full load command for the assignments that are based on a table which is a primary source of a target. It also runs the entire load of powers that are usually assigned to duties in case the date of refresh against the table is null. In case there are a lot of multiple sources, the refresh dates would always trigger an incremental load. DAC would run the full load command structure, in fact, the source tables have no refresh dates.
Q11) Shed light on the merge and upgrade options for DAC version 7.8 and also for the new releases
The merge and update option for DAC version can be carried out by using the merge and update process which is present in the DAC server. The Repository Upgrade is also used for updating DAC. You can use the simplified refresh base from the refresh base menu. It would allow you to update the repository of DAC from an earlier release of Oracle BI. The applications related to a new version can be carried out by comparing and facilitating a report. On the other hand, the base of replace or substitution is carried out when there is a conversion from the older version to a newer one. Quite interestingly, the peer to peer merge can align various DAC instances of repositories related to Data Infrastructure. The base of refresh can also be used for updating the Business Intelligence Applications which are usually present on the DAC server.
Q12) Define the execution related to Micro ETL Plans and also illustrate the process of building and running them
The performance compared to Micro ETL plans are also known as ETL techniques that can be scheduled at the fixed set of intervals. It is important to note that these micro plans related to accomplishments can be classified into half hourly and hourly basis. They are associated with the management of subsets or small places of a subject. The DAC server can also track the time of refresh for various types of tables in the plans related to accomplishments of the micro ETL.
It does so by executing the plans from different plans related to execution. It then utilizes the dates of refresh in the process pertaining to change capture. One can build and run them by creating a copy of the subject area. You can then opt for deactivating the unwanted assignments and can facilitate the creation of new plans related to accomplishments for this area of a subject. 
Q13) Explain the areas where execution pertaining to Micro ETL plans have produced inaccurate results on various kinds of reports
It is important to note that the procedures related to Micro ETL can cause problems related to data inconsistencies. It can also create a massive issue of the availability of data and load on the database pertaining to transactional. One should be aware of the factors that can because the Micro ETL plans to produce wrong information.
In the case of the schemas that share a star hierarchical structure and when one representation is deleted from an assessment plan, the assignments can be inaccurate. An example can be provided in this context to strengthen this fact. If the fact table of the person is refreshed on a frequent basis when compared to the fact table of Revenue, the entire types of diagrams can also facilitate the production of results that are inconsistent. 
On the other hand, if someone deletes the table of dimensions from a Plans related to accomplishments related to ETL, the outside related to the tables of facts would always point to the unspecified rows. The key references would be solved in case the plans related to accomplishments are being run on a DAC server. The users of the reports referred to data warehousing should be aware of various inconsistencies.
On the other side, if you do not comprise the tables of aggregates in the plans related to execution, the information that usually utilizes data would remain inconsistent. On the other hand, if the tables of totals are comprised of the program related to performance, the plans about accomplishments are carried out for processes described to ETL. The tables of a hierarchy are also constructed in the event of every Plan related to achievements related to ETL. In case you avoid overfilling the counters during the ETL processes, the inconsistencies related to data would always occur.

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