- DBMS Tutorial
- What is Database Management System (DBMS)?
- Components of DBMS
- Applications of DBMS
- Three Schema DBMS Architecture
- Difference between DBMS and RDBMS?
- Difference between File Oriented System and DBMS
- Types of Data Models
- DBMS Schema and Instances
- Data Independence and Data Abstraction
- Database Users and Administrator
- DBMS Languages and Interfaces
DBMS ER Model
DBMS Relational Data Model
Database Management System (DBMS) tutorial is all about handling and maintaining the record efficiently. Our DBMS tutorial is creating for learners as well as professionals.
What is Data?
Data can be defined as the description of facts, concepts, or information in a distribute manner applicable for transmission, interpretation, or processing by the human or electronic device. Data is described with the help of characters like Alphabets (A-Z, a-z), numbers (0-9) or special characters (+, -, /, *, <,>, =etc.)
What is Data Item (Field)?
A set of character which is used together to represent a specific data element, e.g., name of the student in a class is represented by the data item, say, NAME.
What is Record?
A record is a group of associated data elements, e.g., Payroll data for an employee include such data fields as name, age, qualification, sex, Basic Pay, DA, HRA, PF, etc.
What is Data File?
File is a collection of related data, e.g., a payroll file might consist of the employee pay record for a company.
Example: Consider the STUDENT File.
What is Information?
It is an organized or confidential record that has some significant value to the receiver.
Data Processing defines manipulating the data (raw data) to make it more helpful.
Data manipulation consists of such functions as classification, sorting, estimation & summarization.
Characteristics of Information
Following are the characteristics of information are as follows:
Information should be accurate. It defines that information should be free from errors & clear. Accuracy also defines that the information is free from bias. Wrong data given to management would output in wrong decisions. As the manager’s decisions are based on the data provided in MIS documents, all managers require accurate information.
Information is of value if it is supported to the user in the form. It is useful and best understood by him. For example, in a business enterprise, top management may require information on key matters in a summarized form and the operation managers in a detailed form.
It defines the current utility of data in decision-making or problem-solving.
It means that information should be made feasible when it is required for a specific purpose and not before and in any case, not after.
The record which is given to a manager must be complete and should meet all his requirements. Incomplete data may output in wrong decisions and thus may prove expensive to the organization.
Information must have a purpose at the time it is communicated to a person or machine, otherwise, it is simply data.
The information should be reliable and externally forced relied upon indicated.
It measures the closeness of the information to the purpose.
Need of Information
- Information is useful for making decisions.
- Information helps managers in lowering the level of uncertainties where they have to make a choice among several available alternatives.
- The information helps the users in tackling problems relating to their respective functional areas.
- Information is used by top management to plan the objectives of the organization and to access whether the objectives are being met in practice.
What is Database?
A database is an organized group of associated data of an organization saved in a formatted way, which is shared by multiple users.
Characteristics of Database
Following are the characteristics of the database are as follows:
A database framework permits several customers to get the database together. To answering different questions from different clients with the similar (base) data is an essential form of an information system. Such a concurrent requirement for data hike the economy of an organization.
Structured and Described Data
A significant characteristic of the database strategy is that the database application does not contain only the data but also the complete description and definition of these data. These definitions are general analysis about the extent, the architecture, the type, and the format of all data and the relationship among the data. This type of saved data is called a metadata (“data about data”).
Separation of Data and Applications
Application program does not require any information about physical data like encoding, design, storage place, etc. It only directs with the administration framework for a database (DBMS), i.e., standardized interface with the support of a standardized language like SQL. The create of the data and the metadata is done by the DBMS. In this method, all the functions can be done isolated from the data. Therefore, database internal reorganizations or development of flexibility do not have any power on the application programming.
Data integrity includes the assurance of the database from unauthorized access (confidentiality) and unauthorized changes.
A transaction is an array of actions which are done inside a database to deliver it from one consistent state to the new consistent state.
One illustration of the transaction is the transmission of an amount of money from one bank account to other account. The debit of money from one account and the credit of it to another account develops together with the logical transaction. This transaction is also an atomic. The debit or credit alone will both get to an inconsistent state. After finishing the transaction (debit and credit), the innovations to both accounts develop into persistence, and the one who contribute the money now has less money on his bank account while the receiver now has a more significant amount.
Data persistence defines that in a DBMS, all record is managed as long as it is not removed unusually. The life period of data needed to be decided directly or indirectly by the customer and must not be dependent on system characteristics. Furthermore, data, once saved in a database, must not be lost. Changes of the database which are done by the transaction are determined. When a transaction is done, even a system crash cannot put the data in danger.