What is a Database?
It is a collection of information related to a particular subject or purpose.
A collection of related data or information grouped together under one logical structure.
A logical collection of related files grouped together by a series of tables as one entity.
A Database is a common data pool, maintained to support the various activities taking place within an organization.
The database is an organized set of data items that reduces duplications of the stored files.
Database Maintenance
A Database cannot be created fully at once. Its creation and maintenance is a gradual and continuous procedure.
The creation and the maintenance of databases is under the influence of a set of user programs known as the Database Management Systems (DBMS).
Data Bank
A Data Bank can be defined as a collection of data, usually for several users, and available to several organizations.
A Data Bank is therefore, a collection of databases.
Types of Database Models
(1). Relational database model
A Relational database is a set of data where all the items are related.
The data elements in a Relational database are stored or organized in tables.
A Table consists of rows and columns.
Each column represents a Field, while a row represents a Record.
A Relational database is flexible and easy to understand.
A Relational database system, has the ability to quickly find and bring information stored in separate tables together using queries, forms, and reports.
This means that, a data element in any one table can be related to any piece of data in another table as long as both tables share common data elements.
Example of Relational database systems is Microsoft Access.
(2). Hierarchical database model
It is a data structure where the data is organized like a family tree or an organization chart. In a Hierarchical database, the records are stored in multiple levels. Units further down the system are subordinate to the ones above.
In other words, the database has branches made up of parent and child records. Each parent record can have multiple child records, but each child can have only one parent.
Components of Data hierarchy
1. Databases (logical collection of related files).
2. Files (collection of related records).
3. Records (collection of related fields).
4. Fields (Is (Facts, attributes a set of related characters).
5. Characters (Alphabets, numbers and special characters or symbols).
(3). Network database model
A Network database model represents many-to-many relationships between data. It allows a data element or record to be related to more than one other data element or record. For example, an employee can be associated with more than one department.
Data Base Management Systems (DBMS)
These are programs used to store and manage files or records containing related information.
A collection of programs required to store and retrieve data from a database.
A DBMS is a tool that allows one to create, maintain, update and store the data within a database.
A DBMS is a complex software, which creates, expands and maintains the database, and it also provides the interface between the user and the data in the database.
A DBMS enables the user to create lists of information in a computer, analyse them, add new information, delete old information, and so on. It allows users to efficiently store information in an orderly manner for quick retrieval.
A DBMS can also be used as a programming tool to write custom-made programs.
Classification of Database Software's
Database software is generally classified into two groups:
1. PC-based database software (or Personal Information Managers — PIMs).
2. Corporate-based database software.
PC-based database software
The PC-based database programs are usually designed for individual users or small businesses. They provide many general features for organizing and analyzing data.
It is a collection of information related to a particular subject or purpose.
A collection of related data or information grouped together under one logical structure.
A logical collection of related files grouped together by a series of tables as one entity.
A Database is a common data pool, maintained to support the various activities taking place within an organization.
The database is an organized set of data items that reduces duplications of the stored files.
Database Maintenance
A Database cannot be created fully at once. Its creation and maintenance is a gradual and continuous procedure.
The creation and the maintenance of databases is under the influence of a set of user programs known as the Database Management Systems (DBMS).
Data Bank
A Data Bank can be defined as a collection of data, usually for several users, and available to several organizations.
A Data Bank is therefore, a collection of databases.
Types of Database Models
(1). Relational database model
A Relational database is a set of data where all the items are related.
The data elements in a Relational database are stored or organized in tables.
A Table consists of rows and columns.
Each column represents a Field, while a row represents a Record.
A Relational database is flexible and easy to understand.
A Relational database system, has the ability to quickly find and bring information stored in separate tables together using queries, forms, and reports.
This means that, a data element in any one table can be related to any piece of data in another table as long as both tables share common data elements.
Example of Relational database systems is Microsoft Access.
(2). Hierarchical database model
It is a data structure where the data is organized like a family tree or an organization chart. In a Hierarchical database, the records are stored in multiple levels. Units further down the system are subordinate to the ones above.
In other words, the database has branches made up of parent and child records. Each parent record can have multiple child records, but each child can have only one parent.
Components of Data hierarchy
1. Databases (logical collection of related files).
2. Files (collection of related records).
3. Records (collection of related fields).
4. Fields (Is (Facts, attributes a set of related characters).
5. Characters (Alphabets, numbers and special characters or symbols).
(3). Network database model
A Network database model represents many-to-many relationships between data. It allows a data element or record to be related to more than one other data element or record. For example, an employee can be associated with more than one department.
Data Base Management Systems (DBMS)
These are programs used to store and manage files or records containing related information.
A collection of programs required to store and retrieve data from a database.
A DBMS is a tool that allows one to create, maintain, update and store the data within a database.
A DBMS is a complex software, which creates, expands and maintains the database, and it also provides the interface between the user and the data in the database.
A DBMS enables the user to create lists of information in a computer, analyse them, add new information, delete old information, and so on. It allows users to efficiently store information in an orderly manner for quick retrieval.
A DBMS can also be used as a programming tool to write custom-made programs.
Classification of Database Software's
Database software is generally classified into two groups:
1. PC-based database software (or Personal Information Managers — PIMs).
2. Corporate-based database software.
PC-based database software
The PC-based database programs are usually designed for individual users or small businesses. They provide many general features for organizing and analyzing data.
For example, they allow users to create database files, enter data, organize that data in various ways, and also create reports.
They do not have strict security features, complicated backup and recovery procedures.
Example of PC-based systems is Microsoft Access.
Corporate database software
They are designed for big corporations that handle large amounts of data.
Issues such as security, data integrity (reliability), backup and recovery are taken seriously to prevent loss of information.
Examples of Corporate-based systems are oracle, Sybase, Progress, etc
Common features of a database packages
They do not have strict security features, complicated backup and recovery procedures.
Example of PC-based systems is Microsoft Access.
Corporate database software
They are designed for big corporations that handle large amounts of data.
Issues such as security, data integrity (reliability), backup and recovery are taken seriously to prevent loss of information.
Examples of Corporate-based systems are oracle, Sybase, Progress, etc
Common features of a database packages
(i). Have facilities for Creating databases.
(ii). Have facilities for Updating records or databases.
(iii). Have facilities for generating Reports.
(iv). Have a Find or Search facility that enables the user to scan through the records in the database so as to find information he she needs.
(v). Allow Sorting that enables the user to organize and arrange the records within the database.
(vi). Contain Query and Filter facilities that specify the information you want the database to search or sort.
(vii). Have a data Validating facility.
Functions of a Database Management System
The DBMS is a set of software, which have several functions in relation to the database as listed below:
1. Creates or constructs the database contents.
2. Interfaces (links) the user to the database contents.
3. Ensures the growth of the database contents through addition of new fields and records onto the database.
4. Maintains the contents of the database. This involves adding new records or files into the database, modifying the already existing records and deleting of the outdated records.
5. It helps the user to sort through the records and compile lists based on any criteria he/she would like to establish.
6. Manages the storage space for the data within the database and keeps track of all the data in the database.
7. It provides flexible processing methods for the contents of the database.
8. Protects the contents of the database against all sorts of damage or misuse, e.g. illegal access.
9. Monitors the usage of the database contents to determine the rarely used data and those that are frequently used, so that they can be made readily available, whenever need arises.
Note. Database Management System (DBMS) is used for database;
1) Creation.
2) Manipulation.
3) Control, and
4) Report generation.
Advantages of Using a DBMS
1. Database systems can be used to store data, retrieve and generate reports.
2. It is easy to maintain the data stored within a database.
3. A DBMS is able to handle large amounts of data.
4. Data is stored in an organized format, i.e. under different field names.
5. Data is quickly and easily accessed or retrieved, as it is properly organized.
6. It helps in linking many database tables and sourcing of data from these tables.
7. It is quite easy to update the data stored within a database.
8. Use of a database tool reduces duplication of the stored files, and the reprocessing of the same data items.
9. It is used to query and display records satisfying a given condition.
10. It is easy to analyse information stored in a database and to prepare summary reports and charts.
11. It’s cost saving
12. Use of Integrated systems is greatly facilitated.
13. A lot of programming time is saved because the DBMS can be used to construct and process files as well as retrieve data.
14. Information supplied to managers is more valuable, because it is based on a widespread collection of data (instead of files, which contain only the data needed for one application).
15. It enables timely and accurate reporting of data
Disadvantages of Databases
1. A Database system requires a big size, very high cost and a lot of time to implement.
2. A Database requires the use of a large-scale computer system.
3. The time involved.
4. A large full-time staff is also required to design, program, and support the implementation of a database.
5. The cost of the database project is a limiting factor for many organizations.
(ii). Have facilities for Updating records or databases.
(iii). Have facilities for generating Reports.
(iv). Have a Find or Search facility that enables the user to scan through the records in the database so as to find information he she needs.
(v). Allow Sorting that enables the user to organize and arrange the records within the database.
(vi). Contain Query and Filter facilities that specify the information you want the database to search or sort.
(vii). Have a data Validating facility.
Functions of a Database Management System
The DBMS is a set of software, which have several functions in relation to the database as listed below:
1. Creates or constructs the database contents.
2. Interfaces (links) the user to the database contents.
3. Ensures the growth of the database contents through addition of new fields and records onto the database.
4. Maintains the contents of the database. This involves adding new records or files into the database, modifying the already existing records and deleting of the outdated records.
5. It helps the user to sort through the records and compile lists based on any criteria he/she would like to establish.
6. Manages the storage space for the data within the database and keeps track of all the data in the database.
7. It provides flexible processing methods for the contents of the database.
8. Protects the contents of the database against all sorts of damage or misuse, e.g. illegal access.
9. Monitors the usage of the database contents to determine the rarely used data and those that are frequently used, so that they can be made readily available, whenever need arises.
Note. Database Management System (DBMS) is used for database;
1) Creation.
2) Manipulation.
3) Control, and
4) Report generation.
Advantages of Using a DBMS
1. Database systems can be used to store data, retrieve and generate reports.
2. It is easy to maintain the data stored within a database.
3. A DBMS is able to handle large amounts of data.
4. Data is stored in an organized format, i.e. under different field names.
5. Data is quickly and easily accessed or retrieved, as it is properly organized.
6. It helps in linking many database tables and sourcing of data from these tables.
7. It is quite easy to update the data stored within a database.
8. Use of a database tool reduces duplication of the stored files, and the reprocessing of the same data items.
9. It is used to query and display records satisfying a given condition.
10. It is easy to analyse information stored in a database and to prepare summary reports and charts.
11. It’s cost saving
12. Use of Integrated systems is greatly facilitated.
13. A lot of programming time is saved because the DBMS can be used to construct and process files as well as retrieve data.
14. Information supplied to managers is more valuable, because it is based on a widespread collection of data (instead of files, which contain only the data needed for one application).
15. It enables timely and accurate reporting of data
Disadvantages of Databases
1. A Database system requires a big size, very high cost and a lot of time to implement.
2. A Database requires the use of a large-scale computer system.
3. The time involved.
4. A large full-time staff is also required to design, program, and support the implementation of a database.
5. The cost of the database project is a limiting factor for many organizations.
