Importing extension mapping documents and their mappings

You can import extension mapping documents and their mappings into the catalog. During the import process, the mappings between source and target assets are created in the catalog.

Before you begin

  • You must have the Information Governance Catalog Information Asset Administrator role.
  • All source assets, target assets, and custom attributes that you use in the extension mapping documents must exist in the catalog before the import.
  • The size of the extension mapping document must not exceed 5 MB. If the file size exceeds this limit, the import fails. Divide the extension mapping document into several smaller files and then import.
  • The extension mapping documents must be in the correct comma-separated value (CSV) format. If the column headings are missing or are incorrect, edit your extension mapping document and change its column headings. Alternatively, you can use a configuration file in an Extensible Markup Language (XML) format to map your existing column headings with correct headings.
    Use the following table to determine if your import file is in the correct format.
    Table 1. Column headings and context of assets according to the origin of the extension mapping document
    Origin of the extension mapping document Column headings Context of assets
    IBM® InfoSphere® Information Governance Catalog The column headings are correct.

    All assets have a fully qualified context.
    IBM InfoSphere FastTrack

    The column headings are correct. Any extra columns are ignored during import.

    All assets have a fully qualified context.
    IBM InfoSphere Discovery

    Column headings, if they exist, are not correct.

    All assets have a fully qualified context.
    Manually created extension mapping document

    Column headings must be: Source Columns, Target Columns, Rule, Function, or Specification Description.

    You can specify a partial context in the CSV file and then a single source and target context when you import.

About this task

You can import an extension mapping document that has the same name as an extension mapping document that exists in the catalog. In this case, the existing extension mapping document and its mappings are deleted from the catalog. They are then replaced by the imported extension mapping document and its mappings. Source and target assets are not deleted.

During the import, the mapping of source-to-target assets is created in the catalog. To map the correct source to the correct target, the import compares the identity of the asset in the extension mapping document with identities that exist in the catalog.
Note: If two assets have the same name but different contexts, the import assigns a mapping to the identity of the first match found. To prevent incorrect mapping, ensure that assets with the same name but different contexts do not exist in the catalog.

Procedure

  1. Click Catalog.
  2. Click Information Assets. In the Create list, click Import Extension Mapping Documents to open the Import Extension Mapping Documents wizard.
  3. In the Select Files window, select at least one extension mapping document file that is in a CSV format. Click Next.
  4. In the Select Import Options window, supply the following information, and then click Next:

    Context for source and target assets
    Type a context in the Context for source assets field or in the Context for target assets field in these cases:
    • You are importing a manually created extension mapping document
    • All assets in all extension mapping documents that you are importing have the same context, and that context is not specified for any of the assets
    Examples:
    • All source assets in the extension mapping documents that you are importing are database columns of the Customer database table in the Americas database schema of the 34C database on host computer JWC. This context is not specified for any of the source assets in the extension mapping documents. In this case, type JWC.34C.Americas.Customer in the Context for source assets field.
    • All target assets in the extension mapping documents that you are importing are database columns in various database schemas on the 34C database on host computer JWC. To specify the database table and database schema context for each of them in the extension mapping documents, type JWC.34C in the Context for target assets field.

    Configuration file
    If the column headings of your extension mapping document are incorrect, download the sample configuration file and edit it to map the existing column headings to correct headings. Alternatively, create a configuration file to manually map the column headings.

  5. Optional: In the Set Extension Mapping Document Properties window, assign stewards and terms, add a short description, and designate which folder to put the extension mapping document in.
  6. Click Import.
    The import can fail for these reasons:
    • The configuration file is not in the correct format, contains incorrect column names, or contains XML errors
    • The extension mapping document that you selected to import is not in the correct format
    • The extension mapping document is larger than 5 MB
    The reason for the failure is displayed in the Errors/Warnings field of the Properties tab. Correct the errors and reimport.
    If the extension mapping document that you selected to import exists in the catalog, a message is displayed. Do either of the following actions:
    • To replace the existing extension mapping document in the catalog, click OK. The selected extension mapping document replaces the existing extension mapping document in the catalog. The source assets, target assets, and custom attributes of the original extension mapping document are not deleted in the catalog.
    • To keep the existing extension mapping document in the catalog, click Cancel.

Example

The extension mapping document that you want to import has a mapping whose source asset is the database table JWC.34C.Americas.Customer. This asset has three parts to its context: JWC, 34C, and Americas. The asset name is Customer.

The import searches the catalog for the identity JWC.34C.Americas.Customer, in this order:
  • Host.database.schema
  • Host.data file.data file structure
  • Host.transformation project.job
  • Application.objectType.method.OutputValue

The import tries to find a host with the name JWC. If a match is found, the import next tries to find a database that is called 34C. If all three parts of the context of the source asset find a match in an existing context in the catalog, that identity is assigned to the imported mapping.

If the import fails to find a host that is called JWC, the import next tries to find a database that is called JWC, a data file that is called JWC, and so on, down the list.

The mapping is created in the catalog with the context of the first match. In this example, JWC.34C.Americas.Customer might be created as a database table mapping. It might also be created as a stage mapping, where JWC is the host name, 34C is the name of the transformation project, and Americas is the job name.