PPT Database

8/7/2019 PPT Database

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Database

A data base is a collection of related data or factsarranged in a specific structure.Eg., details of a college going students

Name, age, place, discipline, college name, phoneno, email ids etc.


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Storing Of DataBaseElements Of Database

1.Forms

Are documents that are filled into createrecords.

2. Reports

Are documents that display a select portion ofa databases information in an easily readformat.


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Storing Of Database

3 Important terms to know about databasesare:

1.Fields:Each piece of data in the address book is

stored in its own location, called a field.Eg., each entry has a field for name,addresses, city, state, etc.


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Storing Of DatabaseTypes of Fields

1. Text Fields: also called string fields, characterfields, or alphanumeric field.

Text fields accepts any string of letters ornumbers that are not used in calculations. Suchas entry of persons name, a companys name,address etc.


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Storing Of Database2. Numeric Fields; ------- stores purely

numeric data. The numberin a numericfield mightrepresentcurrency,

percentages,statistics, quantitiesor anyother valuethatcan be (but notnecessarily) used in calculations. The dataitselfisstored in tablestrictly as a numeric

value,even though the DBMS can displaythe value with formattingcharacterssuchas dollar/percent/decimal/commasetc.


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Storing Of Database3. Date Field or Time Field: stores data or time

entries. These field types convert a date or timeentry into a numeric value, just as dates & timesare stored internally as serial number of days thathave elapsed since a specific start date.


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Storing Of Database4. Logical Fields: storeoneofonlytwo

possible values. You can apply almost

any description forthe data (yesorno,trueor false,on oroff)


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Storing Of Database5. Binary Fields;------ stores binary objects, can

be a graphic image file such as clip art, a

photograph, a screen image, a graphic orformatted text. A binary or (BLOB) also can bean audio file, clip, or other objects.


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Storing Of Database6. Counter Fields; (index or auto number fields)

store a unique numeric value that the DBMSassigns to each record. Because it is possible

for two records to have identical data in sometables ( such as 2 employees with the samename), a counter field ensures that everyrecord will contain at least one completely

unique piece of data. counter fields also maybe used for creating records that numbersequentially, such as invoices.


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Storing Of Database7. Memo Fields; (description field)----- provides

fields for entering notes or comments of any

length with a memo field, you dont specifythe size of the data.


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Storing Of Database2. Records:

One full set of fields i.e., all the related data about

one person or object is called Record. eg. Allinformation for the first person is Record 1, allinformation for the second person is Record 2

3. Tables:

A complete collection of records makes a table.


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Storing Of DataBase Once you have a structure for data, you can

add new data, create reports, & perform othertasks with the data. Eg., you might create acustomer report that groups customers by ZIPcode.

These extra documents, forms & reports along

with the tables, collectively form data base.


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Storing Of DataBase A table organizes each records data by the

same set of fields, but in most databaseapplications, a table can store any number of

records. The fields in the table remain fixed, they

normally remain as they were defined whenthe table was created. There is a finite numberof Facts or fields about each employee


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Storing Of DataBase Each record in the table does not necessarily

have data in every field. For a record to exit,however it must have data in atleast one field.

For eg., a record for an employee must includethe personss name. the employeess name isnot an optional fact.a record may or may notinclude the persons home ph no or date ofbirth, these are considered as optional facts.

The order of fields in a table strictly definesthe location of each type of data in everyrecord. Eg., a phone no field must contain arecords ph no - it cannot contain a personsname or ZIP code.


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Storing Of DataBase The set of fields in any one table provides a

sensible definition of the database for thosewho must access its data. For instance . Youwould expect to find the part number for araditor in an inventory of auto parts, but youshould not expect to view in employees payroll record in the same table.


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Data Base Management System

(DBMS)DBMS is a program,orcollection ofprogramsthat allows any numberofusersto access & modifythe data in adatabase. A DBMS also providestoolsthatenables userstoconstructspecialrequests (called Queries)to find specificrecordsin the database.


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(DBMS)

Features of DBMS

DBMS is a software tool that allows people tostore, access, & process data or facts intouseful information.

Small database programs that run on personal

computers are not referred as databasemanagement programs instead they are calledPersonal Information Managers (PIM)


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(DBMS) A DBMS makes it possible to do many routine

tasks that would otherwise be tedious & timeconsuming without a computer. For eg.,

a) Sort thousands of addresses by ZIP codeb) Find all records of people who live in a

certain state.c) print a list of selected records, such as all real

estate listings that closed escrow last month. DBMS not only stores data, it also allows users

to easily make use of that data. It can siftthrough thousands or even millions of piecsesof data, returning only the data which you

need.


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(DBMS) DBMS can find relationships between data,

such as giving you a list of all accounts thatare 2 months overdue.


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(DBMS)4 important tasks of DBMS

Entering data into the table

Housekeeping tasks, such as updating data,deleting obsolute records, & backing up thedatabase.

Sorting the data i.e, arranging or recordingthe database records.

Obtaining subsets of the data (finding)

Means for multiple users to access & sharedata in the same database by way of networkcomputer system.


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(DBMS)Tools to perform Database Management

Functions:

1. Creating the tables2. Viewing the Records

3. Sorting the Records

4. Creating Queries

5. Generating Reports


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(DBMS)The first step in building any database is ----

creating one or more tables, to create a newdatabase, determine the kind of data to bestored.

1. Name the field

2. Specify the field

3. Specify the field size.


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(DBMS)1. Entering Data in a Table.

2. Viewing Records

3. Sorting records4. Querying a Database

5. Generating Reports.


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Queries

A query is a request that is sent to thedatabase to retrieve data based on givenconditions

Queries allows you to retrieve & modifyinformation in a database

Queries act as a set of records for forms &

reports.

Documents

PPT Database