4.1 Traditional Calculation
The analysis, design, and construction effort assumes a journeyman data modeler and a subject matter expert for each functional area represented in the database's design. A database table consists of fundamental components, which are:
- Table specification
- Column specifications
- Primary key specification
- Foreign key specifications
- Unique key specifications
- Secondary key specifications
An average data model for a application-centric database and single business information system is about:
- 100 Database Schema Tables
- 10 Columns
- 1 Primary Key
- 1 Unique Key (based on business value columns)
- 1.5 Foreign Keys
- 2 Secondary Keys
The design and construction times for these components are:
- Table: 2 hours.
- Column: 30 minutes.
- Primary Key: 30 minutes
- Unique Key: 30 minutes
- Foreign Key: 30 minutes
- Secondary Key: 30 minutes
Thus the overall design and construction time for a typical 100 table database is:
- 200 hours for the tables
- 500 hours for the columns.
- 50 hours for Primary Keys
- 50 hours for Unique Keys
- 75 hours for Foreign Keys
- 100 hours for Secondary Keys
Total for each application centric database: 975 staff hours. The total enterprise staff hours (200 databases): 195,000 (94 staff years). At a cost of $100 per staff hour, the overall cost for all 200 databases is $19.5 million.
4.2 Changed Approach Calculation
The design and construction times for these components are based on the previously developed Data Element Model and Concepts Data Model. The typical database as above are:
- 100 Database Schema Tables
- 10 Columns
- 1 Primary Key
- 1 Unique Key (based on business value columns)
- 1.5 Foreign Keys
- 2 Secondary Keys
This makes the ROI computation equivalent between a traditionally developed database and a Database Logical Model:
- Table: Selection and importing: 5 minutes for each table.
- Column: Importation, review, and modification: 30 minutes per table.
- Primary Key: 10 minutes
- Unique Key: 10 minutes
- Foreign Key: 10 minutes
- Secondary Key: 10 minutes
Thus the overall design and construction time for a typical database with quantities above is:
- 8.3 hours
- 50 hours for the columns.
- 16.6 hours for Primary Keys
- 16.6 hours for Unique Keys
- 16.6 hours for Foreign Keys
- 16.6 hours for Secondary Keys
Total for each application centric database, the changed approach hours is: 141.3 staff hours. The total enterprise staff hours (200 databases): 28,260 hours (13.5 staff years). At a cost of $100 per staff hour, the cost for a single database would be $141,300. The overall cost for all 200 databases is $2.826 million.
Now, because the application of the Data Architecture Reference Model enables the elimination of the 20% overlap, the price for the database would likely be reduced from 141.3 hours to 113 hours and across the enterprise from 28,260 hours to 22,608 hours.
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