MDS - IQA

MDS

Oracle Metadata Services (MDS) is used by Oracle applications components to manage and store their metadata.

Share Data with the SOA Design-Time MDS Repository

The concept is, rather then each project accessing the artifacts(xsd,WSDL,XSL) from the project local folder, access it from the common/shared repository.

This facilitates greater reuse of SOA artifacts such as XML schema,WSDLS,fault policies and rule repository.

Export the Selected Contents of the /apps Folder to a JAR File

Import the Contents of the JAR File into the /apps Folder

Transfer the Selected Contents of the /apps Folder to Another MDS Repository

 Q) What is MDS?

MDS stands for Meta Data Service, it acts as central repository where we keep all common artifacts. 

Q) What are benefits of MDS?

Below are benefits of MDS.

1. Re-usability : Earlier we use to keep the files to local projects so in case we use a file that needs to use across two projects, we end up keeping same file in both the projects. But with the help of MDS, we can keep that file in central location and both the projects can point to that file placed in MDS.

2. In case we need to make changes in common file then we need not to do at multiple places, we need to do that change only in at common location where we kept that file and that changes reflect in all the projects.

3. Business components do not have to look everywhere for the needed information as we put all the information to central repository.

Q) What all types of MDS we have?

 We have two types of MDS as described below.

1. File Based

2. DB Based

Q) What is File based MDS?

 As name suggest, this MDS is based on file system.

 Here we use file system to store all the metadata.

 This MDS is used during development.

 It allow developers to have a light repository available in their local environment that can be easily adapted for development and tests.

Q)What is DB based MDS?

 As name suggest, this MDS is based on database.

 Here we use MDS schema to store all the metadata. 

This MDS repository is used at run time, that means when we develop our code using file based MDS then before we deploy our code to server, we need to move all the files from file based MDS to DB based MDS.

Q) What is syntax of MDS files?

 Below is the syntax where we use MDS files.

oramds:/apps/folder1/folder2/FileName.xsd

Q) What is the file name where MDS configurations stored?

 The adf-config.xml file is a configuration file that is used to store MDS Configurations.

Q) How we identify MDS repository type in adf-config.xml file?

 We identify the MDS repository type in adf-config.xml by following syntax.

File Based MDS: oracle.mds.persistence.stores.file.FileMetadataStore

DB Based MDS : oracle.mds.persistence.stores.db.DBMetadataStore

Q) What type of WSDL file we usually keep in MDS?

 We usually keep Abstract WSDL’s only in MDS.

Graphical MDS:

As we know MDS is used to store artifacts like WSDL, XSD, XSLT etc.

we have two types of MDS, File based MDS and DB based MDS. 

In Oracle SOA 12c, when we use default server which is integrated with Jdeveloper then we can use only Design Time MDS (File Based MDS), Run Time MDS (DB Based MDS) is not supported.

In Oracle SOA 12c release, Oracle provided couple of new options that we can use when we use Design Time MDS, these options were not there in 11g.  Below are options available with Design Time MDS.

Create and Delete folders

Export and Import MDS artifacts

Transfer Artifacts between MDS repositories

Another major change which brought to MDS is that we can publish the files to MDS design time repository from Jdeveloper itself.

In earlier version, to add the file to design time repository we manually need to put the file to file system and made required changes in our code to refer to that MDS file. But with the release of Oracle SOA 12c this all become graphical, we simply publish the file to design time repository by right clicking on the file, this automatically change the required references in the code.