- What is a Database
A database is a single organized collection of data for one or more purposes stored with minimum duplication of data items so as to provide a consistent and controlled pool of data. For example, a school student’s data base will contain data (records) relating to the students, this data may contain records relating to their academic results, school fees, accommodation, parents information and so on for the purpose of managing the students.
- Database management system
A database is usually created using database packages called Database Management System (DBMS) and Relational Database Management System (RDBMS).
So therefore, Database Management System (DBMS) is a software that controls the storage, retrieval and manipulation of data stored in a database. Database Management System (DBMS) makes file easy to store, edit and retrieve effectively.
Examples of a DBMS application
1. MySQL Database
2. MS Access
3. Oracle Database
4. Microsoft SQL Server
5. File Maker
6. No SQL
7. Ms Fox Pro
8. SyBase
9. FoxBase
10. Dbase IV
- Basic database terminologies
The following are some of the basic database terminologies:
· Data: data is defined as raw facts or unprocessed facts or known facts.
· Field: a field is a single piece of attribute about an entity, place, or event. In a student’s database some examples of attributes are surname, date of birth, address, class etc.
· Records: a record is a complete set of attribute (fields) about an entity, place or event.
· Key: a key is a unique identifier or field that can be used to identify a particular record in a database table or file. An example of a key in a Staff file or database is the Staff’s Admin No. no other staff can share the same staff number in that company except that staff. Also a student’s examination No. is a good example of a unique identifier for a particular student which serves as the student’s key.
· File: a file is a single collection of related records. For example, a school database will have an academic file that contains all the academic records of the students in the school.
- Form of database organizations
A data base model is the fundamental specification describing how a database is structured and used; that is how the data is stored, organized, related and manipulated. It defines the set of operation that can be performed on the data.
There are many database models but the three basic database models are:
· Hierarchical database model
· Network database model
· Relational database model
HIERARCHICAL DATABASE MODEL
In hierarchical model, data is organized into an upside-down tree like structure, implying a single upward link in each record to describe the nesting and a sort field to keep the records in a particular order in each same level list. Hierarchical model allows on-to-many relationship between two types of data. The structure is very efficient to describe many relationships in the real world like Mother - Child relationship, Boss and subordinate relationships.
NETWORK MODEL
The network model organizes data using two fundamental constructs, called Records and sets. Records is said to contain fields, while sets define one-to-many relationship between records: One owner, many members like a large company such as MTN, Shoprite or First bank Nigeria Limited.
RELATIONAL MODEL
A relational database is a database that uses tables with rows and columns to show relationships amongst data in a database. And it’s the easiest database and most commonly used database in several organizations today. Relational database is very useful in creating multiple tables linked together using relationship.
- Computer database format
Database packages are used to design a database in a computer. Example of a common database package is Microsoft Access. Microsoft access is a relational database management system used to create and modify database. Here Ms Access is used to illustrate database operation.
The database format in the computer is organized as follows:
To create a database on the computer with MS Access:
LOAD MS ACCESS
To load MS ACCESS do the following.
Click on the windows button on the task bar i.e. the start menu ==> point to all programs and click it ==> point to Microsoft office 2007 and click it ==> select Microsoft Access and click it ==> from the MS ACCESS start up window click on BLANK DATABASE ==> by the right side of the window click inside the file name text box and type your desired database name e.g. ISOLOG School database ==> click on CREATE command button. Then the MS ACCESS Window will load.
- Basic database operations
The basic operations to be considered are:
· Searching
· Sorting
· Modifying
· Generating reports.
ASSIGNMENT
1. Define the database structure.
2. Explain with examples, the five (5) basic field type or data types that we have in database. Which are:
a. Alphabet fields
b. Numeric fields
c. Alphanumeric fields
d. Data fields
e. Boolean fields.
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