May 2017



In Entity Relationship Diagram defines the relationship between entities and their attributes. In example, an ERD contains many-to-many relationships and do not include foreign keys. They areimplied. In an ERD, we are simply visualising the entities, their attributes, and the relation between them. we dont care about where foreign keys go or how to implement that many-to-many relationship. (but we do underline primary keys!)

In a Relational Model we are referring to an implementation of our model. At this point we should be clear about the formats of our attributes, the foreign keys we use, and the linking tables we might need to stitch entities together. A relational model is basically a model of a possible database implementation.
In short, an ERD is an abstract concept of our database, it speaks in entities and attributes, an entity model. A relational model defines formats and relations in a way a database could understand, a data model.

hope this info will be usefull for you!! Enjoy :) 


Integrity Constraints



Before one can start to implement the database tables, one must define the integrity constraints. Integrity means something like 'be right' and consistent. The data in a database must be right and in good condition.

There are the domain integrity, the entity integrity, the referential integrity and the foreign key integrity constraints.

Domain Integrity

Domain integrity means the definition of a valid set of values for an attribute. You define 
- data type, 
- lenght or size
- is null value allowed
- is the value unique or not
for an attribute.

You may also define the default value, the range (values in between) and/or specific values for the attribute. Some DBMS allow you to define the output format and/or input mask for the attribute.

These definitions ensure that a specific attribute will have a right and proper value in the database.


Entity Integrity Constraint

The entity integrity constraint states that primary keys can't be null. There must be a proper value in the primary key field.

This is because the primary key value is used to identify individual rows in a table. If there were null values for primary keys, it would mean that we could not indentify those rows.

On the other hand, there can be null values other than primary key fields. Null value means that one doesn't know the value for that field. Null value is different from zero value or space.

In the Car Rental database in the Car table each car must have a proper and unique Reg_No. There might be a car whose rate is unknown - maybe the car is broken or it is brand new - i.e. the Rate field has a null value. See the picture below.

The entity integrity constraints assure that a spesific row in a table can be identified. 
Picture. Car and CarType tables in the Rent database

Referential Integrity Constraint

The referential integrity constraint is specified between two tables and it is used to maintain the consistency among rows between the two tables.

The rules are:
1. You can't delete a record from a primary table if matching records exist in a related table.
2. You can't change a primary key value in the primary table if that record has related records.
3. You can't enter a value in the foreign key field of the related table that doesn't exist in the primary key of the primary table.
4. However, you can enter a Null value in the foreign key, specifying that the records are unrelated.

Examples

Rule 1. You can't delete any of the rows in the CarType table that are visible in the picture since all the car types are in use in the Car table.

Rule 2. You can't change any of the model_ids in the CarType table since all the car types are in use in the Car table.

Rule 3. The values that you can enter in the model_id field in the Car table must be in the model_id field in the CarType table.

Rule 4. The model_id field in the Car table can have a null value which means that the car type of that car in not known

Foreign Key Integrity Constraint

There are two foreign key integrity constraints: cascade update related fields and cascade delete related rows. These constraints affect the referential integrity constraint.

Cascade Update Related Fields

Any time you change the primary key of a row in the primary table, the foreign key values are updated in the matching rows in the related table. This constraint overrules rule 2 in the referential integrity constraints. 

If this contraint is defined in the relationship between the tables Car and CarType, it is possible to change the model_id in the CarType table. If one should change the model_id 1 (Ford Focus) to model_id 100 in the CarType table, the model_ids in the Car table would change from 1 to 100 (cars ABC-112, ABC-122, ABC-123).

Cascade Delete Related Rows

Any time you delete a row in the primary table, the matching rows are automatically deleted in the related table. This constraint overrules rule 1 in the referential integrity constraints. 

If this contraint is defined in the relationship between the tables Car and CarType, it is possible to delete rows from the CarType table. If one should delete the Ford Focus row from the CarType table, the cars ABC-112, ABC-122, ABC-123 would be deleted from the Car table, too. Source: Gillette Cynthia. 2001. MSCE SQL 2000 Database Design. Chapter 2: Data Modelling. Coriolis Group.


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STA301 Midterm Past Papers Collection



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"VIRTUAL UNIVERSITY OF PAKISTAN"

STA301 Midterm Past Papers Collection



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CS302 MID TERM SOLVED PAST PAPERS MEGA COLLECTION:

1.CS302-MIDTERM SOLVED MCQS_BY MOAAZ.pdf
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2.CS302-Mid Term Solved Mcq's BY MOAAZ AND ASAD.pdf
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3.CS302-Mid Term Solved Subjectives With Ref. BY MOAAZ.pdf
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4.CS302_MID_Term_GIGA_FILE_by_Ishfaq.pdf
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5.CS302 MID TERM SLOVED 3 PAPERS (Sbj+Obj).zip
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6.CS302 Mid Term Solved (5-Papers).rar
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7.CS302 MIDPAPER_Solved_4 Papers_(sbj+obj).rar
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8.CS302-MidTerm_ SOLVED_(6_PAPERS).zip
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9.CS302_Spring2009_2010_MidTerm_BY_SAIDA_ALI.pdf
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10.CS302-2005-2010-Midterm_Solved_MEGA-FILE.doc
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11.CS302_MID_2005_2006_2007.rar
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12.CS302-quiz-solved-for-MID-TERM
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13.MCQS_Mid CS302 Solved.pdf
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14.CS302 Short QS Solved.doc
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15.CS302 Mid 2 Subjective Solved Papers With Ref. BY MASOOM FAIRY.doc
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Here is the Latest Update for Mid Term & Final term Examinations: 
Now Students can Apply For Rescheduling Of Missed/Unplanned Midterm Paper. for Details of Rules and Procedure please Read this Complete Article.





  1. A student may request for re-scheduling of missed/unplanned paper(s) on payment of prescribed fee .
  2. Only missed/unplanned paper(s) can be rescheduled.
  3. The re-schedule chance shall be provided one time only as per the given schedule.
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Goto : Vulms => Student Services =>Examinations Department => Apply for Rescheduling of Papers

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CS504 Midterm Past Papers Collection



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CS607 MID TERM PAPERS

Here we have CS607 - Artificial Intelligence Current and Past Mid Term Papers Fall 2016 at One Place from 17 December 2016 to 29 December 2016.

CS607 MID TERM PAPER SAMPLE 1 FALL 2016

Almost 75% of paper was from the past papers (Objective+Subjective)
CS607 Paper share.docx, 728 KB

Also Read : Virtual University Of Pakistan Jobs - 21/12/2016

CS607 MID TERM PAPER SAMPLE 2 FALL 2016

21/12/2016

13 MCQs were from Mazz Past Paper File.

______ AI treats the brain as a black box and just emulates its functionality.
  • Weak 
  • Strong 
  • Weak and Strong 
  • None of the given
______ AI treats the brain as a black box and just emulates its functionality. 
  • Weak
  • Strong
  • Week and Strong
  • None of the given

The Difference between above two MCQs is weak aur week 


Also Read: MTH202 Past Final Term Papers

CS607 SUBJECTIVE PAPER:


  1. diffrence between monotonic and non monotonic reasoning?
  2. If we execute genetic Algorithm multiple times then will it always result in same solution. (i think ky yeh 5 number ka question tha)
  3. product of 5 and 25 using CLIPS (aik yeh question tha 5 marks ka confirm baat hai is ko zaror yaad kary is question mein thora sa khuch aur bi add tha but wo yaad nai but yeh tha 5 marks ka)
Also Read: Virtual University 8th Convocation List of Position Holders


CS607 MID TERM PAPER SAMPLE 3


  1. difference in mutation and crossover? 2 marks
  2. diff monotonic and non monotonic? 2 marks
  3. Is a fact that "if will probably be raining today" fuzzy or not? give reasons. 3 marks
  4. Briefly explain which part will be selected by dynamic programming from node G to node B if we have two pathsG to B 
  5. A direct line of cost 4.
  6. A path through an interm data node G-A-B with cost 3. 3 marks
  7. A student want to understand about "resolution by refutation" how can you elaborate resolution by refutation with all steps . 5 marks

  8. one 5 marks ka question max min topic ka tha from lecture 10
Also Read: CS201- midterm solved mcqs - Introduction to Programming

CS607 Mid term Paper Sample 4

Mostly MCQs from moaz file
  1. diff mutation and crossover? 2 marks
  2. diff monotonic and non monotonic? 2 marks
  3. A student want to understand about "resolution by refutation" how can you elaborate resolution by refutation with all steps . 5 marks
  4. A tree was given,...us k empty nodes ma value mention krni thi(5)
Also Read: ENG101 ALL Current Mid Term Papers
You Can Also Download CS607 Solved Mid Term Papers, Short Notes, Assignment Solutions, Lecture Wise Questions Answers Files, Solved MCQs, Solved Quiz , CS607 Solved Mid Term Subjective Papers , CS607 Solved Mid Term Objective Papers From This Discussion For Preparation Mid Term Papers of Fall 2015-16.





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CS408 Midterm Past Papers Collection



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MGT501 Midterm Past Papers Collection













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