Fundamentals of Database Systems

...

- Development and Testing

In this face, the firms such as hotels acquire or develop their system depending on the detailed specifications. Many corporations hire software engineers, database developers, and programmers to enable putting into practice the system design. The hotel should consider educating its employees on the use of databases to foster organizational goals actualization. In addition, managers should allow the cashiers and receptionists to validate the system through thorough testing to verify the system’s workability.

- Implementation

After the system withstands the test, the actual installation of an enhanced or new system takes place. The management should endeavor to train its employees particularly the end-users to smoothen evaluation of the business processes. The receptionists can conveniently use the system to identify the vacant guest rooms or halls. If the system negatively responds, the developers resolve the anomaly.

- Operations and maintenance

The primary characteristic of this stage is the operationalization of the system. Accordingly, the developer should endeavor to meet the needs of the sponsor. Regularly, the developer checks and upgrades the software and hardware to facilitate efficient operation. Of importance, the administration team should continue training its hotel workers so that it quickly introduces new features to the existing employees or acquaints new workers to the system.

- Disposition

The disposition stage signifies the end of the system service period. Therefore, it is prudent to terminate the database systematically, so that one preserves the vital information for future retrieval. It is important to note that a hotel enterprise will always dispose of its system if the system becomes obsolete. However, the hotel has to observe the existing legal and regulatory requirements. Additionally, in disposing of the system, it is likely that the hotel may expose vulnerable data that may question the hotel integrity; thus, raising ethical concerns.

-

Functions

- Data dictionary management

The DBMS will store the definition of each data element and their metadata. Metadata includes the relationships between these elements. This function is essential since it hides the user from structural and data dependencies but only provides him with abstractions.

- Data Storage Management

This function is essential for the storage of data and any other data validation rules, report definitions, screen definitions, picture formats, and procedural codes.

- Data transformation and Presentation

The DBMS uses this function to differentiate between logical data formats and physical data formats. As a result, the DBMS will be able to transform any data entered to a preferred data structure.

2.4 A discussion about the 3 steps in database design

Database creation involves three levels namely the conceptual, logical and physical data models.

- Conceptual modeling

This data model, usually, is present in strategic projects because the model describes the entire enterprise. The primary target of this model is the business audience including the customers as it defines only the entities. The conceptual model shows the relationships between entities by using the ER diagrams (New Data Center, 2010) though it may fail to point out cardinality. Significantly, conceptual models can address digitized and non-digitized concepts because it is independent of technology.

- Logical model

Here, one logically arranges the data and maps it into DBMS tables. It has more entities than the conceptual model. In addition, the logical model points out nullity and cardinality. The data that this model handles comes from a primary subject area or a single project. Essentially, users can employ repositories of the shared entities to integrate this model with other logical models. Unlike the above model, the logical models have both attributes and entities definitions. In fact, the data may be independent of the DBMS and one can perform data normalization up-to four normal form (4NF) to make the appropriate forms of relations (New Data Center, 2010).

- Physical Modelling

One should note that the level of complexity rises down the level. In the development of database management systems, the physical modeling calls for the database implementation. Uniquely, physical models have tables, procedures, conditions, domains, and rules. The model precisely defines the data index, data type, and data element. This model uses indices and primary keys to fasten data access and retrieval. De-normalization is present in the cases of data warehouses, but absent in operational data store (New Data Center, 2010). The model design allows it to depend heavily on technology. Lastly but importantly, it stores all the information in the data dictionary.

---------------------------------------------------------------

3. The entity relationship diagram (Week 2 IP)

3.1 An entity relationship diagram

[pic 1]

Fig 1: Screen shot of entity relationship diagram in MS Excel.

The entity relationship diagram in Figure 1 above shows the many relationships between the entities. Events can be in terms of orders. On the other hand, documents are in terms of contracts and receipts. Lastly, organizations are in terms of organization units or staff.

---------------------------------------------------------------

Table 1 below shows a how entities map out to each event.

Table 1: Description of the entity relationship diagram.

Entity

Event

Customers

Guests

Events

Hotel Check-in, Hotel reservation, room reservation