Interview Questions.

Q1. How Dac Determines Tasks Required For Any Given Subject Area ?

According to Oracle Document:

You define a subject place by way of specifying a truth desk or set of reality tables to be the significant desk or tables within the challenge area. When a subject location is defined,

DAC performs the subsequent manner to decide the applicable obligations:

DAC identifies the dimension tables related to the facts and adds these tables to the subject area.

DAC identifies the associated tables, together with aggregates, associated with the truth or dimension tables and adds them to the concern region definition.

DAC identifies the obligations for which the measurement and reality tables listed within the  techniques above are goals tables and adds those duties into the subject region.

Tasks that DAC routinely assigns to a subject region are indicated with the Autogenerated flag (inside the Tasks subtab of the Subject Areas tab).

You can inactivate a mission from taking part in a topic area via selecting the Inactive take a look at box (in the Tasks subtab of the Subject Areas tab). When the Inactive take a look at field is selected, the task remains inactive even if you reassemble the difficulty vicinity.

You can also remove a venture from a subject region the use of the Add/Remove command in the Tasks subtab of the problem Areas tab, however when you get rid of a task it's far simplest eliminated from the subject area until you reassemble the subject place.

DAC identifies the supply tables for the tasks diagnosed in the preceding manner and provides these tables to the difficulty region.

DAC performs this process recursively till all vital obligations have been delivered to the concern location. A challenge is delivered to the difficulty location handiest once, even if it's far related to several tables inside the subject place. DAC then expands or trims the full range of tasks based at the configuration rules, which are defined as configuration tags. This process can be useful resource in depth due to the fact DAC loads all of the items within the source system box into reminiscence earlier than parsing.

Q2. Can You Execute The Sql Scrip Through Dac ? If Yes How ?

Yes, at challenge degree, in execution kind, pick out SQL document. As an advantage to this wer, this newsletter explains the way to run keep techniques in DAC.

Q3. Why We Should Use Dac And Not Control All Execution Through Informatica?

For better overall performance control, which includes growing index, dropping index, truncating before load. Without DAC a custom ETL system can be needed, which has to continue to exist the upgrate.

Q4. How To Export And Import Dac Architecture?

DAC export and import are normally used for backup or repository metadata. The logical gadget and runtime objects can facilitate vital and commodity.

Q5. Shed Light On The Merge And Upgrade Options For Dac Version 7.Eight And Also For The New Releases?

The merge and replace choice for DAC model can be accomplished through the usage of the merge and update procedure that's gift within the DAC server. The Repository Upgrade is likewise used for updating DAC. You can use the simplified refresh base from the refresh base menu. It might allow you to replace the repository of DAC from an earlier release of Oracle BI. The packages related to a new edition may be performed by means of comparing and facilitating a file. On the other hand, the base of replace or substitution is executed whilst there may be a conversion from the older version to a more recent one. Quite apparently, the peer to look merge can align various DAC times of repositories related to Data Infrastructure. The base of refresh also can be used for updating the Business Intelligence Applications which might be commonly present at the DAC server.

Q6. 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 typically tracked for the tables. The tables can be a number one supply or also can be a top target. These number one and supply target tables are generally primarily based at the finished trial of specific pl related to accomplishments. The DAC can even run the whole load command for the assignments which might be based on a table which is a number one supply of a target. It also runs the complete load of powers which are usually assigned to obligations in case the date of refresh in opposition to the desk is null. In case there are a lot of multiple sources, the refresh dates could always trigger an incremental load. DAC could run the total load command shape, in fact, the supply tables don't have any refresh dates.

Q7. How Do You Determine The Informatica Server Maximum Sessions Parameter Setting In Dac?

One you sign in informatica server in Dac customer.

Q8. How Dac Determines The Order Of Task Execution Within An Execution Plan ?

Based on tasks source/goal table, Task segment (extract dim, load reality and so forth) and 'truncate usually' residences, to run them specially order, create project group.

Q9. Can We Facilitate The Running Of Multiple Pl Related To Accomplishments At The Same Time In Dac?

The wer is sure. However, it may be facilitated simplest when the accomplishment manner is not loading into the equal desk.

Q10. Define How Dac Can Determine The Tasks That Are Needed For A Particular Type Of Subject Area?

It is essential to note that a subject area may be described by means of assigning a truth table. Moreover, a subject place can also be certain with the aid of assigning a fixed of fact tables. 

When a topic area is satisfactorily described, DAC also plays the below-stated procedures to evaluate the important tasks associated with information warehousing.

DAC is worried with the identity of the supply tables for the obligations which might be being diagnosed in approaches previous to the only that was called for to perform 

facts warehousing. DAC additionally adds tables to the locations of a subject.

With the help of DAC, one also can get rid of an challenge from a selected situation place by way of using add or do away with command. These instructions are positioned on the tasks tab. 

It is likewise found inside the places of a subject tab. However, while someone deletes a particular mission, it receives eliminated simplest from the location of a topic till and until you refigure the information styles which can be positioned within the locations of be counted.

It is thrilling to note that the responsibilities which can be automatically assigned with the aid of DAC are particular to a topic location. It may be achieved so by way of deciding on the Inactive checkbox. 

It is located within the places of a topic tab.

Moreover, DAC also plays this procedure in a recursive manner. It is also critical to be aware that until all vital assignments are finished, they're typically added to the tab this is located within the subject area.

A assignment is generally introduced to the vicinity of the problem simplest once. DAC also expands or lowers the quantity of functions which are primarily based at the specifications related to configuration.

This approach or technique can be useful resource in depth as DAC installs a huge type of statistics objects into the gadget earlier than the memory of the server is exhausted.

DAC also identifies the desk of dimensions that are worried with the facts and normally provides these records tables to the places of a subject.

It can also correctly find the related facts tables which includes aggregates which can be continually associated with the schedules of dimensions. You also can prefer to add them to the concern place of share. 

Q11. Explain Briefly What Kind Of Dac Repository Objects Held In Source System Containers ?

Subject Areas -- A logical grouping of tables related to a specific challenge or software context. It additionally consists of the responsibilities which might be associated with the tables, 

in addition to the duties required to load the tables. Subject regions are assigned to execution pl, which can be scheduled for full or incremental masses

tables -- Phsyical tables in DB

Indexes -- Just like your physical DB indexes

Tasks -- Unit of labor for loading tables

Task agencies  ---- Grouping of tasks that can be bundled to run as a group

Execution pl -- A facts trformation pl described on subject regions that wishes to be trformed at positive frequencies of time

Schedules -- Determine how frequently execution plan runs.

Q12. Let Say You Can Not Use Dac Scheduler To Schedule You Execution Plan. What Other Options Do You Have ? How You Can Achieve This ?

Use Informatica scheduler.

Q13. What Do You Mean By An Authentication File?

The record of authentication typically authenticates the database in which the repository lies. On the opposite hand, in case you opt for developing an authentication document, then you definitely have the liberty to specify the particular desk and password for a designated set of the database.

Q14. How Dac Handles Parameters At Runtime ?

According to Oracle Document:

During an ETL execution, DAC reads and evaluates all parameters associated with that ETL run, including static and runtime parameters described in DAC, parameters held in flat files, and parameters defined externally to DAC. DAC consolidates all of the parameters for the ETL run, deduplicates any redundant parameters, and then creates an person parameter report for each Informatica consultation. This report contains the evaluated name-value pairs for all parameters, both static and runtime, for every workflow that DAC executes. The parameter file contains a phase for each consultation beneath a workflow. DAC determines the periods beneath a workflow for the duration of runtime by means of the usage of the Informatica pmrep feature ListObjectDependencies.

The naming convention for the parameter record is

....Txt

DAC writes this report to a vicinity particular inside the DAC device assets InformaticaParameterFileLocation. The location specified via the belongings informaticaParameterFileLocation must be similar to the place distinct via the Informatica parameter assets $PMSourcefileDir.

Q15. Define The Execution Related To Micro Etl Pl And Also Illustrate The Process Of Building And Running Them?

The overall performance compared to Micro ETL pl also are called ETL strategies that may be scheduled at the constant set of periods. It is vital to note that those micro pl related to accomplishments can be categorized into 1/2 hourly and hourly basis. They are related to the management of subsets or small locations of a subject. The DAC server can also track the time of refresh for diverse varieties of tables inside the pl associated with accomplishments of the micro ETL.

It does so by means of executing the pl from different pl related to execution. It then utilizes the dates of refresh within the technique bearing on change seize. One can construct and run them through creating a replica of the situation vicinity. You can then choose deactivating the undesirable assignments and might facilitate the creation of new pl associated with accomplishments for this location of a subject. 

Q16. What Is Authentication File ? If You Have Dac Client Installed Can You Access Dac Repository Without Authentication File ?

According to Oracle Document:

When you configure a connection to the DAC Repository, the configuration system includes developing a new authentication file or choosing an existing authentication record. The authentication file authenticates the database in which the repository resides. If you create a brand new authentication file, you'll specify the desk proprietor and password for the database.

Q17. Can We Have Two Dac Server On The Same Machine ?

You can run two DAC servers at the identical gadget as long as they're listening on distinctive ports and pointing to two different repositories.

Q18. Let Say You Are Running The Normal Incremental Load. But Just For Today You Want To Extract Data From Ap_invocies_all From 12/12/2011? How You Can Achieve This ?

Modify the refresh date to be 12/12/2011.

Q19. Explain Dac Export/import?

A manner to import or export DAC repository metadata for upgrade or backup. Logical, System, runtime items may be import/export.

Q20. Over All Architecture Of Dac?

DAC server and DAC Client. They ought to co-discover with Informatica Integration provider, repository provider and Informatica repository.

Q21. Can We Run Multiple Execution Plan At The Same Time In Dac?

Yes. Best if the execution plan aren't loading into the same table or the use of the identical phyiscal table source.

Q22. Difference Between Homogeneous And Heterogeneous Execution Pl?

According to Oracle Document:

Homogeneous:

This type of execution plan extracts records from a couple of times of the identical source device. For instance, a business might have an instance of Oracle EBS 11i in one place and time area and any other instance of Oracle EBS 11i in any other place and time area. In such cases, the timing of information extraction from the distinct instances may be staggered to satisfy your commercial enterprise requirements.

Heterogeneous:

This sort of execution plan extracts facts from one or extra instances of assorted supply systems. For example, a business may have an instance of Siebel 7.8 in one area, an instance of Oracle EBS 11i in every other vicinity, and a 2nd instance of Oracle EBS 11i in but a 3rd vicinity. You can also stagger the timing of data extraction while you use this sort of execution plan.

Q23. Illustrate On The Architecture Of Dac?

DAC comprises of the DAC consumer and the DAC server. It is essential to word they have to realign themselves with Information Integration Service and Information Repository.

Q24. Can Dac Send An Email Just In Case Of Any Failures ?

In DAC Client, toolbar, click electronic mail recipient, then in Tools--> DAC Server setup, Email configuration.

Q25. 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 which might be being assigned to a selected sort of database. On the opposite hand, Task Action refers back to the fact that you can upload multiple sorts of new functionalities associated with the conduct of the responsibilities. It contains of failure motion, achievement action, and failure restart. Moreover, index movement refers to override the exercise of making and dropping indexes.

Q26. Illustrate On The Various Types Of Dac Repository Objects That Are Usually Held In The Containers Related To Source System?

There exist a couple of types of DAC repository gadgets which can be important that allows you to make sure that the information warehousing duties are being finished in a right way.

The following are the diverse items related to the DAC Repository:

Tables: They are also acknowledged with the aid of bodily tables in DAC.

Assignments: They also are popularly referred to as responsibilities and are typically known as a unit of work loading tables.

Indexes: Indexes are also referred to as the bodily DAC indexes which enables the value task of statistics.

Data structure Tables: Data structure tables play a pivotal position in the proper dimension of diverse forms of records. They are also known as the indexes associated with DAC.

Group of Tasks: The class of assignments may be accrued to run as a specific collective organization.

Pl associated with the execution procedure: A records alteration method this is generally described on the locations of a subject. These websites of an difficulty are the middle locations that need to be altered at diverse frequencies in a particular body of thoughts.

Time schedules or time-frequency: It is related to the proper assessment of the going for walks of the execution process.

Q27. How Can You Differentiate Between Homogeneous And Heterogeneous Pl Related To Accomplishments In Dac?

A one-of-a-kind plan related to accomplishments refers to the truth that it can extract records from one or extra probabilities of source structures which are numerous. For example, a business organization could have a score of Siebel 7.8 in one area. On the alternative hand, an example of Oracle EBS 11 may be in every other position. One also can choose surprising the timing of facts extraction when the expert is the usage of this kind of pl associated with accomplishments.  

On the other facet, homogenous pl related to accomplishments additionally pulls database systems from numerous times of the device that has originated from the identical supply. A appropriate instance, in this situation, can be inside the form of the fact that a enterprise could have Oracle EBS 11 in one area and time region and any other portion of EBS 11 in any other function and time area. In the cases referred to above, records extraction timing may be altered in order that the enterprise needs of an business enterprise may be met. 

Q28. 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 accomplished with the assist of the DAC server. However, it is able to be applied only on the project degree. It may be finished by using selecting the SQL document within the method of execution.

Q29. Explain The Areas Where Execution Pertaining To Micro Etl Pl Have Produced Inaccurate Results On Various Kinds Of Reports?

It is critical to notice that the procedures related to Micro ETL can cause issues associated with statistics inconsistencies. It also can create a large trouble of the provision of facts and cargo on the database relating tractional. One have to be privy to the elements which could due to the fact the Micro ETL pl to supply wrong statistics.

In the case of the schemas that percentage a celeb hierarchical shape and whilst one representation is deleted from an evaluation plan, the assignments can be erroneous. An instance may be supplied in this context to bolster this reality. If the fact desk of the individual is refreshed on a common foundation while as compared to the truth table of Revenue, the entire types of diagrams also can facilitate the production of consequences which might be inconsistent. 

On the alternative hand, if a person deletes the table of dimensions from a Pl associated with accomplishments associated with ETL, the outdoor associated with the tables of records would usually point to the unspecified rows. The key references would be solved in case the pl related to accomplishments are being run on a DAC server. The users of the reports referred to records warehousing must be privy to diverse inconsistencies.

On the alternative facet, if you do now not incorporate the tables of aggregates in the pl related to execution, the statistics that commonly utilizes records could remain inconsistent. On the other hand, if the tables of totals are created from the program associated with performance, the pl approximately accomplishments are achieved for tactics described to ETL. The tables of a hierarchy are also built in the event of every Plan related to achievements related to ETL. In case you avoid overfilling the counters during the ETL approaches, the inconsistencies associated with records could usually arise.

Q30. What Are Micro Etl Execution Pl ? How Can You Build And Run Them ?

According to Oracle record:

Micro ETL execution pl are ETL approaches that you agenda at very common intervals, along with hourly or 1/2-hourly. They normally cope with small concern areas or subsets of large issue areas. The DAC tracks refresh dates for tables in micro ETL execution pl one after the other from different execution pl and makes use of those refresh dates in the exchange seize system.

In design -- subject regions, create reproduction of situation place, inactive the undesirable duties and create new execution plan for this challenge location.

Q31. Have You Change Any Of The Dac Parameters ? If So Which One And Why ?

You should understand what are the DAC parameters and the purpose of each. For example, Initial_extract_date can be changed while configure for preliminary full load, so the cost for initial extract date can be used to clear out information from the supply which are older than this date.

Q32. Explain Index, Table And Task Actions In Dac ?

According to Oracle Document:

Index motion: Override the default conduct for dropping and developing indexes.

Table movement: Override the default behavior for truncating and studying tables.

Task action: Can add new capability of venture behavior, consisting of precedinf movement, fulfillment action, failure action, upon failure restart.

Q33. Does Dac Keeps Track Of Refresh Dates For All The Source/goal Tables ?

According to Oracle Document:

Refresh dates are tracked handiest for tables which might be either a number one supply or a primary goal on obligations in a completed run of an execution plan. The DAC runs the overall load command for tasks on which a table is a primary supply or target if the refresh date against the table is null. When there are a couple of primary assets, the earliest of the refresh dates will cause a complete load or an incremental load. If any one of the primary source tables has no refresh date, then the DAC will run the whole load command.

Q34. In Dac How You Can Disable Table Indexes Before Loading And Enable The Index Once Load Is Complete ?

Just drop and recreate index.