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.

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 Document Transcript

  • 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. 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. 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. 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. 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. 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, https://www.facebook.com/Oxus20