ITS 121 - 5th Assignment

A. How to eliminate redundancy in Microsoft Access?

Data redundancy is a data organization issue that allows the unnecessary duplication of data within your Microsoft Access database. A change or modification, to redundant data, requires that you make changes to multiple fields of a database. While this is the expected behaviour for flat file database designs and spreadsheets, it defeats the purpose of relational database designs. The data relationships, inherent in a relational database, should allow you to maintain a single data field, at one location, and make the database’s relational model responsible to port any changes, to that data field, across the database. Redundant data wastes valuable space and creates troubling database maintenance problems.

To eliminate redundant data from your Microsoft Access database, you must take special care to organize the data in your data tables. Normalization is a method of organizing your data to prevent redundancy. Normalization involves establishing and maintaining the integrity of your data tables as well as eliminating inconsistent data dependencies.

Establishing and maintaining integrity requires that you follow the Access prescribed rules to maintain parent-child, table relationships. Eliminating inconsistent, data dependencies involves ensuring that data is housed in the appropriate Access database table. An appropriate table is a table in which the data has some relation to or dependence on the table.

Normalization requires that you adhere to rules, established by the database community, to ensure that data is organized efficiently. These rules are called normal form rules. Normalization may require that you include additional data tables in your Access database. Normal form rules number from one to three, for most applications. The rules are cumulative such that the rules of the 2nd normal form are inclusive of the rules in the 1st normal form. The rules of the 3rd normal form are inclusive of the rules in the 1st and 2nd normal forms, etc.

The rules are defined as follows:

1st normal form: Avoid storing similar data in multiple table fields.

• Eliminate repeating groups in individual tables.
• Create a separate table for each set of related data.
• Identify each set of related data with a primary key.

2nd normal form: Records should be dependent, only, upon a table’s primary key(s)

• Create separate tables for sets of values that apply to multiple records.
• Relate these tables with a foreign key.

3rd normal form: Record fields should be part of the record’s key

• Eliminate fields that do not depend on the key.

The 3rd normal form suggests that fields, that apply to more than one record, should be placed in a separate table. However, this may not be practical solution, particularly for small databases. The inclusion of additional tables may degrade database performance by opening more files than memory space allows. To overcome this limitation, of the third normal form, you may want to apply the third normal form only to data that is expected to change frequently.

Two, more advanced, normal forms have been established with application that is more complex. The Failure to conform to the established rules of these normal forms results in a less perfectly designed database, but the functionality of your database is not affected by avoiding them.

The advanced normal forms are as follows:

4th normal form: Boyce Codd Normal Form (BCNF)

• Eliminate relations with multi-valued dependencies.

5th normal form:

• Create relations that cannot be further decomposed.

B. Differentiate Memo and Text

In an Access database we create tables to hold data. A table is made up of columns, sometimes referred to as attributes or fields. Each of these columns will have a particular data type that defines the data it can hold. For example if we are entering numeric information such as prices, the best data type to use here would be number or currency. For a first name and surname it is better to use a text data type. An alternative to a text data type is what is known as memo. The Microsoft access memo data type will be used to hold text, but it allows a lot more text than the general text data type.

When should we use memo? This is best used in situations where we have to enter a description or even notes. We may wish to store a lot of information about a customer or about a particular transaction.

Generally when using a form we would increase the size of the memo text box and set it's key behavior property to 'New line in field'. This allows us to hit the return key so that the data is not bunched together as one long paragraph.

Keep in mind that you cannot sort or index a Microsoft access memo field. They also have severe limitations when used in queries. Really though you would tend to avoid using them in queries so this is not such a big issue.

In Microsoft Access 2007 we can apply rich text formatting to the memo field both is datasheet and form views. In order to do this we have to set the text format property of the memo field in the table to become 'Rich Text'.

It is always important that the correct data types are used throughout the database. Sometimes this is discovered through trial and error, although good planning can also go a long way to improving performance of the database.

Text

Use for text or combinations of text and numbers, such as addresses, or for numbers that do not require calculations, such as phone numbers, part numbers, or postal codes.

Stores up to 255 characters. The Field Size property controls the maximum number of characters that can be entered.

Memo

Use for lengthy text and numbers, such as notes or descriptions.

Stores up to 65,536 characters.

C. What are DBMS Forms?

ITS 121- 4th assignment

A) Why Do We Gather Data?

B)

Database

A collection of data or information organized for rapid search and retrieval, especially by a computer. Databases are structured to facilitate storage, retrieval, modification, and deletion of data in conjunction with various data-processing operations. A database consists of a file or set of files that can be broken down into records, each of which consists of one or more fields. Fields are the basic units of data storage. Users retrieve database information primarily through queries. Using keywords and sorting commands, users can rapidly search, rearrange, group, and select the field in many records to retrieve or create reports on particular aggregates of data according to the rules of the database management system being used.

DB Table

Is a set of data elements (values) that is organized using a model of vertical columns (which are identified by their name) and horizontal rows. A table has a specified number of columns, but can have any number of rows. Each row is identified by the values appearing in a particular column subset which has been identified as a candidate key.

DB Record

A database record consists of one set of tuples for a given relational table. In a relational database, records correspond to rows in each table.

ITS 121- 2nd assignment

A) Definitions of System.

1. A group of interacting, interrelated, or interdependent elements forming a complex whole.

2. Organization of functionally interactive units for the achievement of a common goal. All systems have inputs, outputs, and feedback, and maintain a basic level of equilibrium.

3. An organized array of individual elements and parts forming and working as a unit.

4. The entire computer system, including input/output devices, the supervisor program or OS, and possibly other software.

5. In building construction, prefabricated assemblies, components, and parts which are combined into single integrated units utilizing industrialized production techniques.

6. A group of bodily organs that have similar structures or work together to perform some function, such as the digestive system, nervous system, and respiratory system.

7. A system is an invisible name given to visible group of things bounded with some defined constraints. It is an orderly, interconnected complex arrangement of parts for the achievement of a common goal.


B) My Differentiation.

The difference between Database Management System (DBMS) and Operating System is that a Database Management System (DBMS) is a set of computer programs that controls the creation, maintenance, and the use of a database. It is a system software package that helps the use of integrated collection of data records and files known as databases while an Operating System is a program designed to run other programs on a computer. A computer’s operating system is its most important program. It is considered the backbone of a computer, managing both software and hardware resources. Operating systems are responsible for everything from the control and allocation of memory to recognizing input from external devices and transmitting output to computer displays. They also manage files on computer hard drives and control peripherals, like printers and scanners.

ITS 121- 1st assignment

A) Definitions of Management.

1. The person or persons who control or direct a business or other enterprise.

2. Combined fields of policy and administration and the people who provide the decisions and supervision necessary to implement the owners' business objectives and achieve stability and growth.

3. Collective administrative heads of a company, institution, business, etc., who are responsible for conducting the affairs of the company (institution, business, etc.) for meeting its short-range and long-range objectives, and for maintaining it as a profit-making organization and/or an ongoing enterprise.

4. Management is a process that is used to accomplish organizational goals; that is, a process that is used to achieve what an organization wants to achieve.

5. Corporate power elites distinguished primarily by their distance from actual productive work and their chronic failure to manage.

6. The planning, organizing, directing, and controlling of the enterprise’s operation so that objectives can be achieved economically and efficiently through others.

7. Management in all business areas and organizational activities are the acts of getting people together to accomplish desired goals and objectives.


B) What is a System?

A system is an invisible name given to visible group of things bounded with some defined constraints. It is an orderly, interconnected complex arrangement of parts for the achievement of a common goal.