DBMS

Data and information

Data: Data are the raw facts and figure with are isolated and uninterpreted generally represented by letter and numbers. Data undergoes processing. E.g. 32, John, 12

Information: The collection of meaningful result obtained after processing raw data. They are generated after processing. E.g. John is 32 years old and he reads in class 12.

Database: The systematic and scientific collection of data that can access quickly whenever required is called database. It is the organized way of collecting and keeping data and information. E.g. Dictionary, telephone directory, marks ledger, attendance register.

DBMS and its advantages

DBMS: DBMS stands for Database Management System which is the collection of software that is used to manage database i.e. storing, manipulating and retrieving data systematically and scientifically. It is a software used to store, process and access data and information whenever required. Eg, MS-Access, MY SQL, Oracle, dBase, Foxpro

Advantages of DBMS.

·         It helps in faster access of data.

·         It helps to reduce duplication of data.

·         It helps to provide security and privacy to data.

·         It helps in data sharing.

·         Easy to modify the data

Differentiate between database and DBMS with examples. [V.imp]

Database	DBMS
It is collection of related data.	It is a software to maintain database.
It is not secured.	It is highly secured.
Data sharing is impossible.	Data can be easily share in a network
Every DBMS has database.	Every database doesn't have DBMS.
E.g, Dictionary, telephone directory	E.g, MY SQL, Oracle.

 

MS-Access:

It is a DBMS developed by Microsoft Corporation for organizing data in the form of tables. It allows user to add, edit, delete, sort, modify, share and print records.

Feature of MS-Access.

·         Easy to store data and information.

·         Easy to enter, edit, delete and display data.

 

Objects / Element of DBMS

A) Table: The primary building block of DBMS where data are organized in the tabular form i.e rows and columns. The columns of database table are called field whereas, rows are called record. Importance of table.

·         Helps to store data in organized group.

·         Easy to sort distinct records.

Fields of table helps to store different types of datas on different topic.

B) Form: The element/object of database which allows user to enter new datas and edit the existing one easily through user friendly interface. Importance of form.

·         It provide user interface through which user can enter data.

·         It helps to modify records.

C) Query: The importance object of database which is used to retrieve/access and interpret the information according the user requirement. Importance of query.

·         It helps in faster access of data.

·         It helps to display information as per the user’s condition.

·         It helps in sorting and filtering of data.

Types of Query

1.       Select query: Used to retrieve data from one or more table depending upon the condition.

2.       Action Query: Used to make changes to records available in database. Types are

3.       Update query: Used to make global (All at once) changes to several records in different table.

4.       Append query: Used to add more records in existing one or more tables.

5.       Delete query: Used to delete one or more record from one or more tables.

6.       Make-table query: Create new table link one or more available tables in database/

D) Report: The object of database which is used to generate result after processing data in a database. It is the effective way of displaying data either in soft copy (monitor) format or hard copy (printed) format. Important of report.

·         It helps to generate summary after processing data.

·         It can be used to generate invoice, bills, statement and labels.

·         It helps to generate result in attractive and effective way.

Data types: The characteristics of field that specifies what kind of data can be stored in the given field is called  data types. 

Following are the data types used in MS-Access.

S.N	Data Type	Purpose/use	Size
1.	Text	Alphanumeric characters	0-255 characters / 256 characters
2.	Memo	Alphanumeric characters	0-65,535 characters / 65,536 characters
3.	Number	Numeric Values	Integer (2 bytes) Long integer (4 bytes)
4.	Date/Time	Date and time data	8 bytes
5.	Currency	Currency data	8 bytes
6.	Auto-number	A sequential unique serial number automatically increased by 1	4 bytes
7.	Yes/No	Logical Values	1 bit
8.	OLE object (Object Link Embedded)	Pictures, audio, video, graphics, documents	1GB
9.	Hyperlink	Link with several applications and websites	2048 characters
10.	Look Wizard	Create a field that allows to select a value.	4 bytes

 

Field properties

Field size: It is used to set the maximum size for the data stored in a given field. For eg, maximum characters (size) store in text field is 256 characters. Default field size is 50.

Format: It is used to display formatted output that means data can be display in different formats and layouts. For eg, < (Display content in lower case), > (Display content in upper case).

Input mask: It is used to specify the format in which data can be entered.

Caption: It is used to display alternate name for the field to make it more descriptive. It can contain 2048 characters.

Default value: It is the value or information that is displayed automatically when we add a new record in table for a field.

Validation rule: It enables user to limit values that can be accepted by particular field. It can contain 2048 characters.

Validation text: The message that is displayed when validation rule is violated or not followed.

Required: It is used to specify whether the data must be enter or not in the particular field.

Indexed: It is used to speed up the searching and sorting of record from the database table.

Some important terms used in DBMS

1) Extension of MS-Access database file is .MDB

2) Primary key (v.imp): The key or field that is used to uniquely identified records from the database table is called primary key. It must be unique and cannot be kept empty (null).

Importance of primary key.

·         It uniquely identifies records.

·         It helps in faster access of data.

·         It helps to prevent duplication of data.

·         It avoids empty (null) values.

·         It is used to establish table relationship.

3) Table relationship: The logical link between two or more than two tables of database using unique key fields is called table relationship. Types are: one to one, one to many, many to many.

4) Sorting: Arranging data in a particular order of field i.e. ascending or descending is called sorting. Helps in faster access of data.

5) Filtering: The process of making selection of record depending upon the supplied criteria is called filtering. Helps in faster access of data.

6) DBA: DBA stands for Database Administrator is a person or specialist who is responsible to manages and monitor overall resources and operation (such as analyzing, planning, operating, implementing and securing) associated with DBMS.

Responsibilities of DBMS.

·         Planning database activities.

·         Securing database and system.

·         Implementing modern tools and technology..

·         Maintaining database.

·         Providing user safety and privacy.

 

Pg 133 table- Data type table

1.      What is a data type in MS Access?
→ It defines the kind of data that can be stored in a field.

2.      Which data type is used to store numbers in MS Access?
→ Number

3.      What data type is used to store long text in MS Access?
→ Long Text

4.      Which data type stores date and time values?
→ Date/Time

5.      Which data type in MS Access is used to store currency

values?
→ Currency

6.      Which data type is used to store only Yes or No values?
→ Yes/No

7.      What is the default data type in MS Access?
→ Short Text

8.      Which data type allows hyperlinks to be stored?
→ Hyperlink

9.      Which data type can store attachments like files and

images?
→ Attachment

10.  Name a data type that can store values like 3.14 or 10.5.
→ Number (with field size set to "Double" or "Single")

11.  Which data type in MS Access is used to store

characters or alphabets?
→ Short Text

12.  Which data type stores values automatically incremented

by Access?
→ AutoNumber

13.  What is the maximum character limit of Short Text

data type in MS Access?
→ 255 characters

14.  What is the main use of the AutoNumber data type?
→ To generate unique values automatically for each

record. 

15.  Which data type is suitable for storing essays or long

paragraphs?
→ Long Text

16.  Which data type can be used to display or store a photo

in MS Access?
→ Attachment or OLE Object

17.  What is the use of the OLE Object data type in MS

Access?
→ To store objects like images, Word documents,

or Excel files.

18.  Which data type is best for storing website URLs?
→ Hyperlink

19.  Which data type would you choose to store true/false

values?
→ Yes/No

20.  Can a field with the Number data type store letters?
→ No

21.  Which data type allows you to store both date and time

together?
→ Date/Time

22.  Name a data type that helps in logical (Boolean) decisions.
→ Yes/No

23.  Which data type is suitable to store salary data?
→ Currency

24.  Which field type cannot contain duplicate values if set as

Primary Key?
→ AutoNumber (commonly used with Primary Key)

25.  Can you apply calculations on fields with Number data

 type?
→ Yes