Monday, 20 August 2012

Informatica Repository-Repository Server


The PowerCenter repository resides on a relational database. The repository database tables contain the instructions required to extract, transform, and load data. PowerCenter Client applications access the repository database tables through the Repository Server.
You add metadata to the repository tables when you perform tasks in the PowerCenter Client application, such as creating users, analyzing sources, developing mappings or mapplets, or creating workflows. The PowerCenter Server reads metadata created in the Client application when you run a workflow. The PowerCenter Server also creates metadata, such as start and finish times of a session or session status.
You can develop global and local repositories to share metadata:
  • Global repository. The global repository is the hub of the domain. Use the global repository to store common objects that multiple developers can use through shortcuts. These objects may include operational or Application source definitions, reusable transformations, mapplets, and mappings.
  • Local repositories. A local repository is within a domain that is not the global repository. Use local repositories for development. From a local repository, you can create shortcuts to objects in shared folders in the global repository. These objects typically include source definitions, common dimensions and lookups, and enterprise standard transformations. You can also create copies of objects in non-shared folders.
  • Version control. A versioned repository can store multiple copies, or versions, of an object. Each version is a separate object with unique properties. PowerCenter version control features allow you to efficiently develop, test, and deploy metadata into production.
You can connect to a repository, back up, delete, or restore repositories using pmrep, a command line program.
You can view much of the metadata in the Repository Manager. The Informatica Metadata Exchange (MX) provides a set of relational views that allow easy SQL access to the Informatica metadata repository. 

 Repository Server Administration Console:

Use the Repository Server Administration Console to administer Repository Servers and repositories. A Repository Server can manage multiple repositories. You use the Repository Server Administration Console to create and administer the repository through the Repository Server.
You can use the Administration Console to perform the following tasks:
  • Add, edit, and remove repository configurations.
  • Export and import repository configurations.
  • Create a repository.
  • Promote a local repository to a global repository.
  • Copy a repository.
  • Delete a repository from the database.
  • Back up and restore a repository.
  • Start, stop, enable, and disable repositories.
  • Send repository notification messages.
  • Register and unregister a repository.
  • Propagate domain connection information for a repository.
  • View repository connections and locks.
  • Close repository connections.
  • Register and remove repository plug-ins.
  • Upgrade a repository.

Repository Server

The Repository Server manages repository connection requests from client applications. For each repository database registered with the Repository Server, it configures and manages a Repository Agent process. The Repository Server also monitors the status of running Repository Agents, and sends repository object notification messages to client applications.
The Repository Agent is a separate, multi-threaded process that retrieves, inserts, and updates metadata in the repository database tables. The Repository Agent ensures the consistency of metadata in the repository by employing object locking.
Repository Manager
Use the Repository Manager to administer your repositories. The Repository Manager allows you to navigate through multiple folders and repositories, and perform the following tasks:
  • Manage the repository. You can perform repository management functions, such as copying, creating, starting, and shutting down repositories. You launch the Repository Server Administration Console to perform these functions.
  • Implement repository security. You can create, edit, and delete repository users and user groups. You can assign and revoke repository privileges and folder permissions.
  • Perform folder functions. You can create, edit, copy, and delete folders. Work you perform in the Designer and Workflow Manager is stored in folders. If you want to share metadata, you can configure a folder to be shared.
  • View metadata. You can analyze sources, targets, mappings, and shortcut dependencies, search by keyword, and view the properties of repository objects.

Repository Manager Windows

The Repository Manager can display the following windows:
  • Navigator. Displays all objects that you create in the Repository Manager, the Designer, and the Workflow Manager. It is organized first by repository, then by folder and folder version. Viewable objects include sources, targets, dimensions, cubes, mappings, mapplets, transformations, sessions, and workflows. You can also view folder versions and business components.
  • Main. Provides properties of the object selected in the Navigator window. The columns in this window change depending on the object selected in the Navigator window.
  • Dependency. Shows dependencies on sources, targets, mappings, and shortcuts for objects selected in either the Navigator or Main window.
  • Output. Provides the output of tasks executed within the Repository Manager, such as creating a repository.

Repository Objects

You create repository objects using the Repository Manager, Designer, and Workflow Manager Client tools. You can view the following objects in the Navigator window of the Repository Manager:
  • Source definitions. Definitions of database objects (tables, views, synonyms) or files that provide source data.
  • Target definitions. Definitions of database objects or files that contain the target data.
  • Multi-dimensional metadata. Target definitions that are configured as cubes and dimensions.
  • Mappings. A set of source and target definitions along with transformations containing business logic that you build into the transformation. These are the instructions that the PowerCenter Server uses to transform and move data.
  • Reusable transformations. Transformations that you can use in multiple mappings.
  • Mapplets. A set of transformations that you can use in multiple mappings.
  • Sessions and workflows. Sessions and workflows store information about how and when the PowerCenter Server moves data. A workflow is a set of instructions that describes how and when to run tasks related to extracting, transforming, and loading data. A session is a type of task that you can put in a workflow. Each session corresponds to a single mapping.
The goal of the design process is to create mappings that depict the flow of data between sources and targets, including changes made to the data before it reaches the targets. However, before you can create a mapping, you must first create or import source and target definitions. You might also want to create reusable objects, such as reusable transformations or mapplets.
Perform the following design tasks in the Designer:
  1. Import source definitions. Use the Source Analyzer to connect to the sources and import the source definitions.
  1. Create or import target definitions. Use the Warehouse Designer to define relational, flat file, or XML targets to receive data from sources. You can import target definitions from a relational database or a flat file, or you can manually create a target definition.
  1. Create the target tables. If you add a target definition to the repository that does not exist in a relational database, you need to create target tables in your target database. You do this by generating and executing the necessary SQL code within the Warehouse Designer.
  1. Design mappings. Once you have source and target definitions in the repository, you can create mappings in the Mapping Designer. A mapping is a set of source and target definitions linked by transformation objects that define the rules for data transformation. A transformation is an object that performs a specific function in a mapping, such as looking up data or performing aggregation.
  1. Create mapping objects. Optionally, you can create reusable objects for use in multiple mappings. Use the Transformation Developer to create reusable transformations. Use the Mapplet Designer to create mapplets. A mapplet is a set of transformations that may contain sources and transformations.
  1. Debug mappings. Use the Mapping Designer to debug a valid mapping to gain troubleshooting information about data and error conditions.
  1. Import and export repository objects. You can import and export repository objects, such as sources, targets, transformations, mapplets, and mappings to archive or share metadata.

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