Thursday, December 29, 2011

Re: (VU-Study-Corner) cs403 assignment

salam;

mn ne assignment to bna li hy but mjy kuch kami lgti hy  baki jitni b hy theek hy agr koi kami hy to plz add kr lain is mn thanks...........

jitna mj se ho ska hy mn ne kr diya hy............




2011/12/28 اویس اعوان <mc110202428@vu.edu.pk>

السلام علیکم و رحمتہ اللہ

Sister
Primary keys un attributes ya columns ko kehty hn jo k ksi bhi table k andr se distinct record select krny k liye use hoty hn..
Like in Product table, P_ID is a good candidate of being Primary Key because through P_ID go to a specific single record.

Foreign is a type of attribute through which we can select a single or multiple records relating to the same primary key existing in another table.

Example:

Suppose there are two tables Customer and Order

Customer:
     Cus_ID      PK
     CName
     Address


Order:
    O_ID      PK
    Description
    Amount   
    Cus_ID      FK


Here in table named Order, there is an attribute named Cus_ID. This attribute will help us to select one or more records which are made by a specific Customer.

Hope it would be helpful :)
والسلام







اویس | محمود | اعوان
MC110202428
PWCT01, Wah Cantt.
awais.mehmood@uettaxila.edu.pk

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