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Database Terminology :
1) Data : Data is the raw fact which may or may not give any sense.
It is a set of static value which are stored in a table.
2) Information : It is the proceed data or output which is
obtained after manipulating raw data.
3) Data Processing : The act of
manipulating raw data in order to obtain meaningful information s called data
processing. The steps of data processing are :
Data collection Ã
Filing ---> Codingà Data Entryà Data updating Ã
Data Processing Ã
DecodingÃ
Report Printing
4) Database : Database is an
organized and systematic collection of
data of a particular subject which is easily accessed , edited and
managed.
Eg. Telephone directory, marks
ledger, Salary sheet, flight schedule, dictionary etc.
a)
Importance
/ Advantages of database:
·
Data can be stored in a small area
·
Saves time in searching, updating and editing
data in computerized data base.
5)
Computerized
VS Non computerized database :
Database organized in computer
using electronic device and software is called computerized / electronic
database. Whereas, database in sheet of paper, organized manually is known as
non- computerized database. Computerized data base access data conveniently.
Data updating, editing and deletion of records will be faster, stores large
number of data in a small device.
But non computerized database is
very difficult to access, update and search data. It creates problems while
handling large amount of data.
6)
DBMS(
Database management System):
It is the collection of software
that manages, manipulate and analyze data in database. It collects the data in
table, process and analyze them using query and provides required information
through report.
Example : MS- Access, Dbase,
Foxbase, Foxpro, Oracle, Clipper, Sybase,
7)
RDBMS(
Relational Database management System):
RDBMS is the
collection of software that manages database by linking and sharing in two or
more tables. It update and analyze the
data from one or more database. Eg.Oracle, Ms Access, MS SQL Server etc.
Functions of DBMS :
·
Maintains data validity
·
Controls data redundancy( duplication)
·
Provides facilities for sharing of data
·
Maintains standardization of data
8)
Elements of data base :
Field : Field is the column heading of a database. It is the
smallest unit of table where similar type of data are stored. It is also known
as attribute. Eg, Name, Age, Address,
Phone etc.
Record: A record is a collection of multiple related fields, which
gives a complete information about an individual. It is a row in a database
which is also known as tuple.
(i)
7. MS- Access : It is a relational database management system
that arranges data in tables, allows user to query data, and provides
information through report. It is developed by Microsoft Corporation US, and
available under MS – Office family.
Features of MS- Access :
·
Relational database management system.
·
It incorporates SQL and VB language.
·
Query, form report are the useful objects.
8. Objects / Elements of MS- Access( DBMS):
(i) Table
(ii) Form (iii) Query (iv) Report
(v)
Pages (vi) Modules
(vii) Macros
Table :
Meaning
:
It is the primary object and
basic structure of DBMS. It stores/collects the data about the specific topics
in row and columns. It is also known as relation.
a) Importance/Advantages
of Table :
(i)
It facilitates storing, grouping and sharing data
(ii)
It is the basic structure of DBMS for storing
information
b) Elements/
Parts of a table :
i) Fields, Records, primary key,
cell etc. are the elements of table.
ii) Primary Key : A primary key is the field that uniquely identifies
record in a table. Primary key that consists of two or more attributes(fields)
is called composite primary key. The
main feature of primary key filed are – it does not hold duplicate data, nor it
accepts blanks(null) data.
Advantage/ Importance of primary
key:
·
Primary
key field controls data redundancy( duplication of data).
·
It allows to create relationship between two or
more tables.
·
Facilitates data searching and sorting.
Sorting
: Grouping records in ascending or descending order on the basic of one or more
field(s) is known as sorting. Its advantages are ; (i) Since, it arranges the
data in particular order, it helps to locate the data easily in a table. (ii)
It increases the readability of data in a table.
9)
Filtering :
It is the process of extracting data from underlying table. It provides the
data from the table, which meets the given criteria. There are three types of
filtering;
i.
Filter by form
ii.
Filter by selection
iii.
Advanced filter
10)
Indexing : It is the process of organizing data such
way, so that searching and retrieval of
data would be faster. MS- access supports two types of indexing;
i.
Unique index : Accepts no duplicate value
ii.
Duplicate index: Accepts duplicate value in the
fields.
Advantages: It control data redundancy. It speeds up data searching
in the table.
11)
Methods of
creating /opening table.
There are basically three ways of
creating table.
a)
Design View
b)
By entering data( Data sheet view)
c)
Using wizard
a)
Design view :
Design view allows user to create table by defining field size and field
properties. A design view window is split into two parts i.e. Filed grid pane and field property pane.
User can easily modify the table structure in this view.
b)
Datasheet view
:It allows user to create table by entering data directly. Field names are
defined by the user as a column heading by renaming the exiting fields. Data
can be entered, edited and deleted in this view, easily.
c)
Using wizard
: It allows user to create table by selecting the pre- defined fields name,
size and properties.
Design View VS Datasheet view
i.
Fields size and properties can be defined in design
view, where as they can not be defined in datasheet view.
ii.
Table structure can be modified in design view but not
in datasheet view.
iii.
Direct data entry, editing and deleting are possible in
datasheet view, where as they are not possible directly in design view.
Data Type supported by MS- Access
Data types are attribute for a
field which determines what type of data the field contains. Access supports
following Ten types of data.
|
Data Type |
Description |
Size |
Example |
|
1.
Text |
Accepts
alpha numeric characters. It is default data type. |
0
to 255 characters. |
Name,
Address |
|
2.Memo |
Alpha
numeric characters with punctuation marks. Used for long description |
0
to 65,535 character |
Remarks,
Description, Auto biography |
|
3.
Number |
Byte,
Integer, Single, Long integer, Double, decimal |
1,
2,4,8,8 bytes |
Population,
Area, Length |
|
4.
Currency |
Monetary
data with currency symbol. |
8
bytes |
Tax,
Fee, Salary |
|
5.Date
& Time |
Date
and Time value. Date range 100 to 9999 years |
8
bytes |
Date
of Birth, Time of Arrival |
|
6.Autonumber |
Sequential
or random number, data entry not required |
4
bytes |
Serial
number, Code number |
|
7.
Yes/No/ Boolean |
Logical
data type. Format: True/False, On/Off |
1
bit |
Gender,
cash/credit |
|
8.OLE
Object |
Picture,
sound, video |
Upto
1 Gb |
Map
Of Nepal, music video |
|
9.
Hyper link |
A
link address |
Upto
2048 chr |
URl,
Email address |
|
10.
Look up wizard |
Data
from another table/ combo box or list box |
4
bytes |
List
of month, List of districts |
The Field Properties:
The field properties area are
the attribute of field which provides the control over a field. Different data
types have different filed properties .They are as follows .
|
Field Property |
Description |
|
Size |
Sets
the maximum size of data accepted by the field. |
|
Format |
Displays
data in different format. Text
and Memo data type uses ; @,&,>,< Date
& Time uses ; General Date/time, Long date/Time, short date/Time, medium
date/Time Yes/No
data type uses; On/off, True/False |
|
Caption |
Label
or explanatory name for the field name. Maximum upto 2048 characters. |
|
Default
Value |
Automatically
repeats/sets the value in a particular field of each record ,while entering
data in the table. It is not applied to Auto number and OLE Object. |
|
Validation
Rule |
To
limit the values to be accepted by the field. Eg; not null, >100, between 1 and 100 etc. |
|
Validation
Text |
Sets
the message, when validation rule is violated . Eg; ‘Enter less than 100’ etc. |
|
Required |
Sets
whether the value required or not. It is set to Yes, if data entry is required
for the field, other wise No. |
|
Indexed |
Speeds
up data searching and retrieval. It has two option. i.
No( no indexing) ii. Yes (duplicate OK) Yes( No duplicate) |
|
Input
Mask |
Facilitates
user by providing Pattern/ way of data to be entered and viewed . |
Rules for naming Field:
i. A field name can be upto 64 characters.
ii. It can contains
letters, numbers, spaces and other symbols except perid(.), exclamation(!),
acent grave(~), and brackets ([]).
FORM
Form
is a database object that can be used to enter, edit, or display data from a
table or a query. It provides the interface between MS Access and user because it displays the records on the
screen. There are two types of from; i.
Main form ii. Sub form
Methods of creating form :
i)
Design view
ii)
Auto Form
iii)
Form wizard
Layout of Form :
i)
Data sheet
ii)
Tabular
iii)
Columnar
iv)
Justified
Control of Form:
Tab,
Radio Button, Check box, List box, Combo box,
Option group, command button etc.
QUERY
It is an object of MS Access
which is used to view, change and analyze the data in different ways from table
or query. It asks a questions about the data stored in the tables and returns
the results. It uses criteria to analyze and extract the require information.
Types of Query:
1. Select Query : It retrieves the data from one or more tables or
queries and displays information bys using given criteria.
2. Action query : The query which directly changes or moves one or
more records in one operation . It deletes, update and group the records.
a) Update query: It makes global changes to a group of records in
one or more tables.
b) Delete query: It deletes one or more records from one or
more tables.
c) Append query : It adds a
group of records from one or more tables to the existing table at the end of
record.
d) Make table query : It
creates a new table from all or part of the data in one or more tables for a
backup copy of a table.
Besides above, Cross tab query, SQL query and
Parameter query are also the different types of query.
Criteria : Criteria
are the expression that defines on e or more condition in order to obtain
specific set of records or data from query or filter. Eg. Like , Not like, Between , <>100 etc.
Operators : Operators are the sing or symbol or words that
are used to compare and calculate the data in query. Access supports the
following type of operators.
i.
Arithmetic operator : +, -, *, /, \. MOD
ii.
Comparison Operator:
=, >, <. >=. <= , Like, Not Like, In, Between
iii.
Relational operator:
AND, OR, NOT
REPORT
It
is a database object which provides the information in printed form. It groups
and presents the formatted information from underlying table, query and SQL
statement.
Methods
of creating Report :
iv)
Design view
v)
Auto Report
vi)
report wizard
Layout( Print view) of Report :
i.
Tabular
ii.
Columnar
iii.
Justified
Different parts of Report :
i. Report
Header : It contains the title of report.
ii. Page Header : Information contains at
the first of each page
iii. Detail: Display detail information from
selected fields.
iv. Page Footer : Information contains at
the last of each page
iv. Report footer: It contains the
information at the end of report.
Page Orientation of Report :
·
Portrait : Vertical
Orientation of page
·
Landscape : Horizontal
orientation of page.
Differences
|
Data |
Information |
|
i. It is a raw or un proceeded fact. ii.
It may or may not give sense. |
i.
It is proceeded output or result. ii.
It provides fact output or sense . |
|
Field |
Record |
|
i.
It is a piece of information. ii.
It is a column heading or vertical orientation of table |
i.
It is a complete information about an individual ii.
It is a row or horizontal orientation of a table. |
|
Database |
DBMS |
|
i.
It is an organized collection of data. ii.
It may be computerized or non computerized. |
i.
It is the collection program or software. ii.
It is an electrical or only computerized . |
|
Sorting |
Indexing |
|
i.
Group the records in order ii.
It is not a field property. |
i.
Performs fast retrieve of data from table. ii.
It is a field property. |
|
Query |
Form |
|
i.
It is used to extract, and change the data from one or more tables and
queries. ii.
The source of query is table and query itself. iii.
It is a question about the data stored in a table. iv.
Data sorting can be performed. |
i.
It is used to enter and edit the data. ii.
The source of form is Table. iii.
It is an interface between user and MS – Access. iv.
Data sorting can not be performed. |
|
Query |
Report |
|
i.
It is used to extract, and change the data from one or more tables and
queries. ii.
It can be select query and action query. iii.
The source of query is table and query itself. |
i.
It is used to display the information in printed form. ii.
Report can be columnar, tabular and justified. iii.
The source of Report is Table, form and query. |
|
Text |
Memo |
|
i.
It accepts alpha numeric character. ii.
It accepts maximum 255 characters. |
i.
It accepts alpha numeric characters as well as punctuation marks. ii.
It accepts maximum 65,535 characters. |
|
Action Query |
Select Query |
|
i.
It changes(delete, update) the data. ii.
It does not display information but changes the data directly in table, when
it is run. |
i.
It only retrieves required data on the basis of criteria. ii.
It displays information on the screen when it is run. |
|
Number |
Currency |
|
i.
It accepts numeric data i.e. byte, integer, long integer, single , double
etc. ii.
It accepts long integer, by default. |
i. It accepts numeric data preceded with currency sign. ii.
It accepts two decimal places, by default. Eg. $4.00 |
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