Top 10 Oracle MDS Repository Interview questions and answers

The blog provides the commonly asked Oracle SOA Meta Data Store (MDS Repository)  Interview questions & answers to be helpful for beginners and experienced professionals.

1) What is MDS in Oracle SOA Suite ?

Metadata depicts the data about data and SOA MDS stands for Oracle Meta Data Service which acts as the Central Repository for storing , retrieving the service metadata in the Oracle Fusion Middleware.  XML, XSD, WSDL, SCA Composites, BPEL Process, Oracle ADF Pages are few example of the metadata components.

2) How Oracle MDS is useful in SOA Suite ?

The below advantages are provided by Oracle MDS Repository:

  • Provides all resources to be available at the Central Repository location to be accessed by any component
  • A Change in Metadata resources provides the updated metadata to other components 
  • Avoids redundancy and ensure consistency.
  • Metadata configured during design time is used at application runtime using metadata service layer.

3) What are the types of MDS Repository?

MDS Repository can be defined as: 

  • File based MDS Repository
  • DB based MDS Repository

4) Explain File-Based MDS Repository?

MDS used file based repository by default for storing / retrieving the service metadata. The file based repository provides the below usages:

  1. File based MDS Repositories are considered light-weight 
  2. File based MDS Repository is used primarily in local environments for configuring and validating the repository integrations 
  3. Reduces integration time to connect to external Database repositories and managing all configurations locally
  4. File based repositories provides directory structure to configure and maintain the data
  5. The file-based repository is located in <JDeveloper_Home>/integration folder

5) Explain DB-Based MDS Repository?

The Database based repository provides the below usages:

  • Database repositories are primarily used for real-time integrations in production environment
  • Database repositories resides in the Database Schema ( Tables, Objects) and are created using the Oracle Repository Creation Utility (RCU)  Tool 

6)  Which configuration file is used for storing the MDS configurations?

The adf-config.xml configuration file stores the MDS Configurations

7) How many types of WSDL can be stored in MDS Repository ?

MDS Repository only stores Abstract WSDLs.

8) How can we identify which MDS repository type used for Web Service ?

The MDS Repository type is stored in adf-config.xml

  • File Based MDS: oracle.mds.persistence.stores.file.FileMetadataStore
  • DB Based MDS : oracle.mds.persistence.stores.db.DBMetadataStore

9) Describe the reason for the MDS Error: MDS-00054: The file to be loaded does not exist ? 

The oramds: reference for the WSDL document could not be evaluated at run-time

10) Explain the steps for  transferring MDS artifacts from design time to run time

The below given steps can be performed :

  • SOA Design Time MDS connection -> Transfer
  • Select the resources to Transfer ( WSDL, XSD, Target MDS Connection) 
  • Click OK 
  • Refresh the Target MDS Connection and artifacts should be available now.