Oracle Data Integrator (ODI) Interview questions and answers

What are the types of Variables?

1) Global

2) Project

A variable is an object that stores a single value. This value can be a string, a number or a date. The value is stored in Oracle Data Integrator, and can be updated at run-time.

The value of a variable can be updated from the result of a query executed on a logical schema. For example, it can retrieve the current date and time from a database.

A variable can be created as a global variable or in a project. Global variables can be used in all projects, while project variables can only be used within the project in which they are defined.

Where we can use variables?

ariables can be used in all Oracle Data Integrator expressions:

ü  Mapping,

ü  Filters,

ü  Joins,

ü  Constraints,

What is Work Repository   ?

Each work repository is attached to a master repository, therefore, information about the physical connection to a work repository is stored in the master repository it is attached to.
Defining a connection to a work repository consists of defining a connection to a master repository, then selecting one of the work repositories attached to this master repository.

What is Master Repository ?

The Master Repository is a data structure containing information on the topology of a company's IT resources, on security and on version management of projects and data models. This repository is stored on a relational database accessible in client/server mode from the different modules.

Generally, only one master repository is necessary.

However, in exceptional circumstances, it may be necessary to create several master repositories in one of the following cases:

·         Project construction over several sites not linked by a high-speed network (off-site development, for example).

·         Necessity to clearly separate the interfaces' operating environments (development, test, production), including on the database containing the master repository. This may be the case if these environments are on several sites.

What is a Procedure?

A Procedure is a reusable component that allows you to group actions that do not fit in the Interface framework. (That is load a target datastore from one or more sources).

A Procedure is a sequence of commands launched on logical schemas. It has a group of associated options. These options parameterize whether or not a command should be executed as well as the code of the commands.

What is  Model ?

An Oracle Model is a set of datastores corresponding to views and tables contained in an Oracle Schema. A model is always based on a Logical Schema.  In a given Context, the Logical Schema corresponds to a Physical Schema. The Data Schema of this Physical Schema contains the Oracle model's tables and views.

What is a Package ?

The package is the biggest execution unit in Oracle Data Integrator. A package is made of a sequence of steps organized in an execution diagram.

What is User Parameters?

Oracle Data Integrator saves user parameters such as default directories, windows positions,etc.

User parameters are saved in the userpref.xml file in /bin.

What is a Project?

A project is a group of objects developed using Oracle Data Integrator.

What is Folder?

Certain objects in a project are organized into folders and sub-folders.

What is an Interface?

An interface consists of a set of rules that define the loading of a Datastore or a temporary target structure from one or more source Datastores.

What is Sequence?

A sequence is an  variable automatically incremented when used. Between two uses the value is persistent.

The sequences are usable like variable in interfaces, procedures, steps, ...

A sequence can also be defined outside a project (global scope), in order to be used in all projects.

What is User Functions ?

User functions enable to define customized functions or "functions aliases", for which you will define technology-dependant implementations. They are usable in the interfaces and procedures.

What is Marker?

Elements of a project may be flagged in order to reflect the methodology or organization of the developments.

Flags are defined using the markers. These markers are organized into groups, and can be applied to most objects in a project.

What is Scenario?

When a package, interface, procedure or variable component is finished, it is compiled in a scenario. A scenario is the execution unit  for production, that can be scheduled.

What is Context?

A context is a set of resources allowing the operation or simulation of one or more data processing applications. Contexts allow the same jobs (Reverse, Data Quality Control, Package, etc) to be executed on different databases and/or schemas.

In Oracle Data Integrator, a context allows logical objects (logical agents, logical schemas) to be linked with physical objects (physical agents, physical schemas).

What is Memos?

A memo is an unlimited amount of text attached to virtually any object, visible on its Memo tab. When an object has a memo attached, the icon appears next to it.

What is Sequences?

A sequence is a variable that increments itself each time it is used. Between two uses, the value can be stored in the repository or managed within an external RDBMS table.

Oracle Data Integrator supports two types of sequences:

·         Standard sequences, whose last value is stored in the Repository.

·         Specific sequences , whose last value is stored in an RDBMS table cell. Oracle Data Integrator undertakes to read the value, to lock the row (for concurrent updates) and to update the row after the last increment.

What is Session?

A session is an execution (of a scenario, an interface, a package or a procedure, ...) undertaken by an execution agent. A session is made up of steps which are made up of tasks.

What is Session Tasks?

The task is the smallest execution unit. It corresponds to a procedure command in a KM, a procedure, assignment of a variable, etc