The Information Warehouse Domain includes the storage and maintenance of the warehouse data and all of the captured metadata and prepares them for delivery to the end user. The Components of the information warehouse are:
- Information Warehouse Data
- Information Warehouse Metadata
4.1. Information Management
Information Management is responsible for the data content of the Information Warehouse. This includes:
- Data Administration
- Database Administration
4.1.1. Data Administration
Data Administration is responsible for managing the data assets of the enterprise.
Data Administration features include:
- Providing the policies and procedures to manage the logical specifications which comprise the information models of the enterprise
- Metadata creation and management through the Metadata Repository
- Distributed performance of activities with central coordination
- Research support for operational and warehouse activities
- Providing standard data definitions across lines of business.
4.2. Metadata
Metadata is the information that describes the data that is stored in the data warehouse. There are three basic types of Metadata:
- User Metadata
- Operational Metadata
- Technical Metadata
User Metadata describes the data warehouse in terms of what is the user trying to accomplish when he/she accesses the data. This includes what data is available, what it means (definition, information value and content), where it came from (source), how it got there (transformation, conversion, summarization, etc.) and where it can be found within the warehouse structure.
Operational Metadata describes the “as of” information about the data and how much data is available on a given topic. For example inventory data may be available “as of” the most recent end of month for a given distribution point, while summary information about inventory flow by distribution point per quarter is available from second quarter of 2001 through the last quarter of the previous year.
Technical Metadata describes the structure and flow of the data into, within and out of the data warehouse. This includes the database design of all of the components of the warehouse (atomic and datamart) and the physical process flow used to cleanse, format, transform and derive the data.
4.2.1. Metadata Repository
Metadata describes the business processes and data that are required to support the operation of the enterprise. Metadata is captured and managed in a database that is described as the Metadata Repository. From a business perspective, the repository should be viewed as the ‘Yellow Pages’ of business information.
The metadata in the repository provides business and technical users with information about the contents of the Information Warehouse Domain. The information about the Information Warehouse Domain includes:
- Common business definitions of enterprise data
- Data sources
- What relationships exist between data
- Accepted usage conventions
- Formulas that were used to calculate derived data fields
- Descriptions of reference tables that are used in translations and transformations
- Descriptions of reports
- Bbusiness requirements and rules that are used to design application systems
- Application design documentation
- Other technical specifications.
The Metadata Repository provides the business community with:
- Easy access and navigation of business information, requirements, rules, and reports
- Impact analysis capabilities
- The ability to capture and store information.
The Metadata Repository is used to capture and report on design documentation. It is also used to:
- Automatically generate:
- Report programs
- Update and maintenance programs
- Database and file technical descriptors
- Data extract and transformation programs or utilities
- Easily navigate through the information provided in the Information Warehouse
- Automatically interface with Systems Management tools
- Manage and administer the Information Warehouse Domain.
The Metadata Repository must be highly flexible (extensible) and provide a robust set of tools and capabilities to manage the metadata. The tools and capabilities include:
- A command language
- Report generation utilities
- Object oriented features such as:
- Polymorphism
- Inheritance
- Encapsulation
- Class libraries
- The ability to efficiently support large volumes of data with complex relationships.
The sub-components of the Metadata Repository are:
- Metadata Repository Access
- Dictionary
- Directory.
4.2.1.1.Metadata Repository Access
Metadata Repository Access is the vehicle for retrieving, storing, and manipulating information in the repository. Metadata Repository Access features include:
- Easy to use batch and on-line reporting capabilities
- Multi-user, concurrent access
- Work group check in/out with versioning that enables the sharing of:
- Design objects
- Program source code
- Models
- Descriptions
- A point-and-click, graphical user interface (GUI)
- Meta-model navigation
- Batch load and update facilities that automatically interface to other Computer Aided Software Engineering (CASE) and modeling tools
- User verification to ensure that security is maintained
- Query management with a performance governor.
4.2.1.2.Dictionary
The Dictionary is the database that is used to store the metadata that describes the Information Warehouse Domain and how data is used across the enterprise.
Dictionary features include:
- An audit facility for the purposes of control and administration
- Flexible extensibility
- A command language for manipulating the data structures
- Security to the element level
- Change/version control for managing the progression/flow of changes throughout the data warehouse development life-cycle
- Support for metadata types which encompass:
- Systems definitions that contain process models and data models that are instantiated and maintained during the conceptual, logical and physical phases of the development life cycle
- Data acquisition specifications for extracting data from source systems and populating the Information Warehouse including:
- The business rules for transforming data
- The code used to transform source system data
- Data Warehouse data formats
- Source system data formats.
4.2.1.3.Information Directory
The Information Directory is the facility that relates the metadata objects. The directory describes the relationships as to:
- Where used
- How used
- Who uses the object.
Directory features include:
- Flexible definition of views and reports
- Configuration management
- Extensibility for the definition of new relationships between objects
- A command language to implement customizations
- Security to the element level.
- Batch load and update facilities that automatically interface to other modeling tools
User Access features include:
- Batch and on-line reporting capabilities
- Multi-user, concurrent access
- A point-and-click, graphical user interface (GUI)
- Meta-model navigation
- User verification to ensure that security is maintained