| Most of the information systems nowadays are | | | | controls and understanding who really knows the |
| multi-user systems, that is, they should have a | | | | meaning of data |
| database that many users can use. Application | | | | 5. Over what period of time are you interested in |
| programs depend on the database. A good | | | | these data? Do you need historical trends, current |
| database design that can accommodate and | | | | “snapshot” values, and/or estimates or |
| support all application programs is necessary for | | | | projections? If a characteristic of an object |
| an information system to deliver the intended | | | | changes over time, must you know the obsolete |
| functionality. The system reliability is a measure of | | | | values?—Cardinality and time dimensions of |
| the reliability of any of its worst components. | | | | data |
| Business analyst ignores the importance of | | | | 6. Are all instances of each object the same? |
| gathering information for the database design. He | | | | That is, are there special kinds of each object |
| she should seek answers to the following | | | | that are described or handled differently by the |
| questions before database design: | | | | organizations? Can some objects be summaries |
| 1. What are the subjects/objects of the business? | | | | or combinations of more detailed |
| What types of people, places, things, materials, | | | | objects?—Supertypes, subtypes, and |
| events, etc. are used in this business? How many | | | | aggregations |
| instances of each object might exist?—Data | | | | 7. Which events imply associations between |
| entities and their descriptions. Business analyst | | | | various objects? What natural activities or |
| must have thorough knowledge about the data | | | | transactions of the business involve handling data |
| that will be used in application | | | | about several objects of the same or different |
| 2. What unique characteristic(s) distinguishes one | | | | type?—Relationships, and their cardinality and |
| object from other similar objects? Will this | | | | degree |
| distinguishing feature change over time or is it | | | | 8. Is each activity or event always handled the |
| permanent? Can we miss this characteristic of an | | | | same way or are there special circumstances |
| object even though we know the object | | | | when it is handled differently? Can an event occur |
| exists?—Primary key | | | | with the involvement of only some of the |
| 3. What are the characteristics for each object? | | | | objects, or must all objects be involved? Can the |
| On what basis are objects referenced, selected, | | | | associations between objects change over time |
| qualified, sorted, and categorized? What | | | | (for example, employees change departments)? |
| information about the object is necessary to run | | | | Are values for data characteristics limited in any |
| the business?—Attributes and secondary keys | | | | way?—Integrity rules, minimum and maximum |
| 4. How do you use these data? That is, are you | | | | cardinality, time dimensions of data |
| the source of the data for the organization, do | | | | A business analyst must have equal interest and |
| you refer to the data, do you modify it, or do | | | | rigour in database details, as he/she determines |
| you destroy it? Who is not permitted to use | | | | functional and non-functional requirements of an |
| these data? Who is responsible for establishing | | | | application. |
| legitimate values for this data?—Security | | | | |