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Fundamentals of Database Systems Questions and Answers


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Fundamentals of Database Systems questions and answers with explanation for fresher's and experienced for interview, competitive examination and entrance test.

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Fundamentals of Database Systems Questions and Answers

  1. 1. https://www.facebook. com/Oxus20 Abdul Rahman Sherzad Page 1 of 5 PART I – Single and Multiple choices: 1) The common types of entities are:  Strong entities  Weak entities  Associative entities  All of the above 2) The logical representation of an organization's data is called a(n):  Database model  Entity-relationship model  Relationship systems design  Database entity diagram 3) Customers, cars, and parts are examples of:  Entities  Attributes  Cardinals  Relationships 4) An entity type whose existence depends on another entity type is called a(n) _____ entity.  Strong  Weak  Codependent  Variant 5) A(n) _____ is the relationship between a weak entity type and its owner.  Member chain  Jump path  Chain link  identifying relationship 6) A property or characteristic of an entity type that is of interest to the organization is called a(n):  Attribute  Coexisting entity  Relationship  Cross-function 7) A person's name, birthday, and social security number are all examples of:  Attributes  Entities  Relationships  Descriptors 8) An attribute that can be broken down into smaller parts is called a(n) _____ attribute.  Associative  Simple  Composite  Complex
  2. 2. https://www.facebook. com/Oxus20 Abdul Rahman Sherzad Page 2 of 5 9) The following figure shows an example of:  A composite attribute  A relational attribute  A derived attribute  A multivalued attribute 10) An attribute that can be calculated from related attribute values is called a(n) _____ attribute.  Simple  Composite  Multivalued  Derived 11) The total quiz points for a student for an entire semester is a(n) _____ attribute.  Derived  Mixed  Stored  Addressed 12) Which of the following criteria should be considered when selecting an identifier?  Choose an identifier that is stable  Choose an identifier that will not be null  Choose an identifier that doesn’t have large composite attributes  All of the above 13) Which of the following conditions should exist if an associative entity is to be created?  All the relationships for the participating entities are many-to-many  The new associative entity has independent meaning  The new associative entity participates in independent relationships  All of the above
  3. 3. https://www.facebook. com/Oxus20 Abdul Rahman Sherzad Page 3 of 5 14) The number of entity types that participate in a relationship is called the:  Number  identifying characteristic  Degree  Counter 15) A relationship between the instances of a single entity type is called a(n) _____ relationship.  Ternary  Primary  Binary  Unary Part II - Basic Terms and Data Model: 1) Persons can take the following roles around database systems:  End users  DB designers  DB administrators  Application Programmers Decide for each of the following activities, to which role it belongs by writing the respective number in the box.  Developing the conceptual schema  Managing user accounts, hardware resources, and backups during the lifetime of the database  Programming of software that is using the database  Choice of DBMS  Analyze requirements for the database  Programming of a graphical user interface for the database  Gathering of information about the application field
  4. 4. https://www.facebook. com/Oxus20 Abdul Rahman Sherzad Page 4 of 5 2) Classification of Database Management Systems: a) Name three different data models that can be used in DBMS: Relational Model Object Relational Model Network Model b) Which data model is used by MySQL? Relational Model c) Is MySQL a single-user or a multi-user DBMS? Multi-User Part III – ER to Relational Mapping: 1) Name and explain in brief (just briefly), the steps that are needed to transform an ER diagram into a relational schema. 1. Mapping Strong Entities 2. Mapping Weak Entities 3. Mapping One-to-One relationship 4. Mapping One-to-Many relationship 5. Mapping Many-to-Many relationship 6. Mapping Multi-Valued attributes 7. Mapping N-ary relationship
  5. 5. https://www.facebook. com/Oxus20 Abdul Rahman Sherzad Page 5 of 5 Part IV – Challenges: 1) You have the following two figures. Both using the one-to-many relation but in different ways. Are they the same? Yes / No, Give reason. Using the above "One-to-Many" relationship the implementation is simple and easy; but support one depth and level of relationship, as for instance, a sub-forum can't have other sub-forums! Using the above recursive relationship it supports both one level and as many level as possible of nested relationships. For instance, a forum can have a sub-forum; the sub-forum still can have other sub-forums and yet that other sub-forums can have sub-forums and so on, so forth. 2) There is something wrong with the following query (The problem is the single quotation-marks with the string). Try to rewrite it with correct syntax using two different methods. SELECT * FROM lecturers WHERE signatory = 'If you tell the truth, you don't have to remember anything';  SELECT * FROM lecturers WHERE signatory = "If you tell the truth, you don't have to remember anything";  SELECT * FROM lecturers WHERE signatory = 'If you tell the truth, you don't have to remember anything'; Forum Sub Forumhas 1 m Forum has 1 mmain sub Figure 1 - One-to-Man Figure 2 - Recursive
  6. 6. OXUS20 is a non-profit society with the aim of changing education for the better by providing education and assistance to IT and computer science professionals. ‫آکعیَض‬02‫یک‬‫اًجوي‬‫غیر‬‫اًتفاعی‬‫تا‬‫ّذف‬‫تمَیت‬ ٍ‫تغییر‬‫پرٍرغ‬ ٍ ‫آهَزغ‬‫طریك‬ ‫از‬ِ‫ارائ‬‫آهَزغ‬ٍ‫کوک‬ِ‫ت‬ ‫هتخصصاى‬‫علَم‬‫کاهپیَتر‬‫اظت‬. ‫ایي‬ ‫ًام‬‫اًجوي‬‫پر‬ َ‫آه‬ ‫دریای‬ ‫از‬ ِ‫ترگرفت‬‫آى‬ ‫هَج‬ ‫دظت‬ ِ‫ک‬ ًِ‫هیا‬ ‫آظیای‬ ‫رٍد‬ ‫تریي‬ ‫آب‬‫تیاًگر‬‫اظتعذاد‬‫ایي‬ ِ‫ًْفت‬ ‫ّای‬‫اًجوي‬ُ‫تَد‬،‫از‬ ‫دریا‬ ‫ایي‬ ٍ ‫هاٍرای‬ ٍ ِ‫گرفت‬ ِ‫ظرچؽو‬ ‫پاهیر‬ ‫کْي‬ ‫ّای‬ ٌِ‫داه‬‫خذهات‬ ِ‫ارای‬ ‫ّذف‬ ‫دریا‬ ‫حالت‬ ‫ایي‬ ِ‫ک‬ ‫هیکٌذ‬ ‫آتیاری‬ ‫را‬ ‫افغاًعتاى‬ ‫تاظتاًی‬ ‫ظرزهیي‬ ‫ؼوالی‬ ‫اًجوي‬‫اًعکاض‬ ‫را‬.‫هیذّذ‬ ‫آکعیَض‬02‫هاًٌذ‬ ‫خذهاتی‬ ‫تا‬ ‫دارد‬ ‫ًظر‬ ‫در‬‫ایجاد‬‫فضای‬‫علوی‬ ‫ؼکَفایی‬ ٍ ‫خاللیت‬ ‫تراًگیختي‬ ٍ ‫اظتعذادّا‬ ‫تجلی‬ ‫ترای‬ ‫هٌاظة‬‫داًػ‬ ٍ ‫هحصالى‬ ،‫پصٍّاى‬ٍ ‫علوی‬ ِ‫ترًاه‬ ‫فَق‬ ‫ّای‬ ‫فعالیت‬ ‫ظاختي‬ ‫ًْادهٌذ‬،‫کارتردی‬‫ؼٌاظایی‬‫عاللوٌذ‬ ٍ ِ‫ًخث‬ ،‫خالق‬ ‫افراد‬‫در‬ ‫آًْا‬ ‫هؽارکت‬ ‫از‬ ‫گیری‬ ُ‫تْر‬ ٍ ‫علوی‬ ‫فضای‬ ‫ارتمای‬ٍ ‫تَلیذ‬ ‫ّوچَى‬ ِ‫جاهع‬ ٍ ‫آهَزؼی‬ ‫هراکس‬ ‫دیگر‬ ٍ ‫ّا‬ ‫پٌَّتَى‬‫تخصصی‬ ‫علوی‬ ‫ًؽریات‬ ‫اًتؽار‬‫تکٌالَشی‬ ٍ ‫عصری‬ ‫علَم‬ ‫هَثر‬ ‫ؼکل‬ ِ‫ت‬ ‫را‬ ‫هعلَهاتی‬ِ‫جاهع‬ ‫افراد‬ ‫آهال‬ ِ‫ت‬ ‫رظیذى‬ ‫ّای‬ ُ‫را‬ ٍ ‫پصٍّػ‬ ٍ ‫تحمیك‬ ،‫تذریط‬ ٌِ‫زهی‬ ‫ؼذى‬ ‫تْتر‬ ِ‫ّرچ‬ ‫راظتای‬ ‫در‬ ِ‫جاهع‬ ‫در‬ ‫آى‬ .‫هیعازد‬ ‫فراّن‬ ‫را‬ Follow us on Facebook,