A set of characters that represents a valid value is known as data. Data is also a raw and unprocessed form of facts and figures. For example, 3, Deepti,17 etc.
Information is the data , which has been processed and has processed. For example, Roll no. 3 is Deepti who is 17 years old.
Database is the collection of data, which is stored in a systematic manner and can be used to retrieve information quickly and efficiently from a large set of data.
A database may consist one or more tables. A table holds information in the form of rows and columns.
Rows are referred to as record and also known as tuple. A record is a set of related information that belongs to a particular object. For example- student record may contain roll number, name, total marks.
Columns are referred to as fields. A field describes a specific property of a record, that is why a field is also known as an attribute. It describes information about an entity, e.g. roll no is an attribute of a student.
A database is basically used by developers, administrators and the end users.
Developers design and develops a database.
Administrator keep track on database and check authorisation to provide access to the users.
End users are the group of people who really use the database.
The DBMS (Database Management System) is a comprised record keeping system or a software that enables you to create, store, modify and extract information from a database.
Flat File – The data is stored in a single table/ file with plain text format. Fields in the record are separated using delimiters. It is suitable for less amount of data,
Relational databases- Data is stored in multiple tables and can be accessed by establishing a relationship between the tables by using a common field.
Data Redundancy – It refers to duplication of data. It occurs when the same piece of data is duplicated unnecessarily multiple times in a database.
Data inconsistency – It refers to data which is not in consistent form i.e. two files may contain different data of the same entity.
Data Concurrency- Many user can access and modify the shared data at the same time , without violating the data consistency.
Data Integrity- Maintaining and assuring the accuracy and consistency of data is called data integrity.
Primary key – It is a set of one or more fields that uniquely identifies each row in a table. It does not contain any null or blank value as well as duplicate value. A table can have only one primary key.
Composite Primary key- It refers to a combination of two or more attributes(fields) that uniquely identify the records in the table.
Foreign key- It is a field or set of field that is used to establish a relation between the two tables.
Candidate key- A table might have one or more fields that may uniquely identify the records. Such fields are called Candidate keys.
Microsoft Access is the most popular and powerful Relational Database Management . It is an integral part of MS-Office suite. It organises the data in the form of tables and provides the facility to create relationship between them, using common fields.
There are four main objects in any database- Tables, Queries, Forms and Reports.
A table stores the complete data in a structured manner, in the form of rows and columns. Every table can have finite number of columns but infinite number of rows.
Queries- Enables us to retrieve records from one or more tables of a database or different databases that meet a specific criteria.
Forms- It has an attractive interface that accepts data from the user and inserts it in the corresponding table or query.
Reports- These are used to display the selected data in a printable format. These are used for decision making and analysing the data by the organisations.
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