Relational Database Management System
Relational Database Management System
It is the most widely used type of DBMS. In addition to store and timely retrieval of data, it also preserves the relation between different sets of data.
Relationship: It is a link or association between several entries.
List of different types of relationship
- One to one e.g: Driver and car
- One to many e.g: Teacher and students
- Many to many e.g: Books and readers
- Many to one e.g: Students and school
Field properties are the sets of characteristics that are associated with each field.
Field properties of MS Access
Difference between database and DBMS
|Database ||DBMS |
|1. It is a collection of data or related information. ||1. It is a software package to manage database |
|2. It consists of data. ||2. It manages data in the database. |
|3. It is a part of DBMS ||3. It is a software system which contains database. |
|Example: phone diary, data of SLC exam, etc. ||Example: FoxPro, Access, etc. |
A primary key is the field that uniquely identifies in a table. Each record in the table must be unique. Every table has only one primary key.
Types of primary key
- Compound (Composite key):A compound key is a key that consists of multiple columns because one column is not sufficient.
- Foreign key:A foreign key is the linking pin between two tables.
A record row in a database is called tuple.
A wizard is a small program that interviews us, asking questions about what we want to accomplish, then it takes over answers and creates the table, query or whatever according to our specification.
Difference between Design view and Wizard
|Design view ||Wizard |
|It takes more time. ||It saves our time |
|We can make our design. ||We can choose formats from premade ones. |
|We can create any field according to our requirement. ||We can copy fields from any of the simple table. |
Things to remember
- Field properties are the sets of characteristics that are associated with each field.
- A primary key is the field that uniquely identifies in a table.
- A compound key is a key that consists of multiple columns because one column is not sufficient unique.
- A record row in a database is called tuple.
- A foreign key is the linking pin between two tables.
- It includes every relationship which established among the people.
- There can be more than one community in a society. Community smaller than society.
- It is a network of social relationships which cannot see or touched.
- common interests and common objectives are not necessary for society.
Videos for Relational Database Management System
Assigning Primary Key in Microsoft Access
Microsoft Access 2007 2010 part 4 (Relational Database)
Microsoft Access 2007 Table Data Types and Field Properties
Microsoft Access 2010 - The Primary Key
Questions and Answers
A Rotational Database Management System (RDBMS) is the most widely used type of DBMS which stores database in multiple tables which can be linked with each other on the basis of key field.
Any two examples of RDBMS are as follows:
The primary key is a special filed or group of fields in a table that has unique value for each record and does not accept the duplicate value for a field.
Any two uses of primary key are as follows:
- To identify each record of a table.
- To set the relationship between tables.
The field properties is the plane that displays the list of properties associated with each field data type and determine how the values in the field are stored.
A caption field property is defined as the property that allows a user to set a descriptive label for the field. The maximum characters of a caption is 2048 characters long.
The property that allows a user to specify the maximum number of characters that can be stored in a field is known as field size property. The default field size of text field data type is 50.
The property that allows a user to display data in different formats and used to specify the appearance of the value when displayed is known as format field property.
The property that specifies a pattern for all data to be entered and makes data entry easier is known as input mask property.
Data validation is the process of ensuring that a program operates on clean, correct and usefuldata.
It is useful in database because it checks and controls data to be entered in the field and defines expression to limit the values that can be entered.
The property that speeds up searching and sorting of records based on field is known as property of a field.
Primary key is a special field or group of fields in the table that uniquely identifies each record from the database. The primary key does not accept duplicate value for a field and it does not allow a user to leave the field blank or null.
The importance of primary key are:
1) To identify each record of a table uniquely within very short time.
2) To reduce and control duplication of the record in a table.
3) To set the relationship between tables.
A unique field or combination of fields in a linked table whose value matches with a primary key in another table is known as foreign key. The group of primary key that consists of two or more attributes is called composite key.
MS-Access is a Relational Database Management System developed by Microsoft Corpotration. It is used to store and manipulate large amount of data in multiple tables. The objects of MS-Access are:
Referential integrity is a set of rules used by RDBMS to make sure that the relationships between tables are valid and that the related data is not accidentally changed or deleted.