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Consider the relations City (city_name, state) Hotel (name, address) City_hotel (hotel_name, city_name, owner)
Answer the following queries in relational algebra(i) Find out the names and address of hotels in Agra.(ii) List the names of cities that have no hotel.(iii) List the names of the hotels owned through ‘Taj Group'.
Ans: (i) Π name, address ( σ city_name= ‘Agra' (Hotelname=city_name City_hotel))(ii) Π city_name (City) - Π city_name(City_hotel)(iii) Π hotel_name ( σ owner='Taj Group' (City_hotel))
Explain the concepts of relational data model? Relational Data Model - The relational model was first introduced through Prof. E.F. Codd of the IBM Research in the year 1970
What are the basic objects of the data dictionary? Tables Domains Data elements Structures Foreign Keys
Define the concept of Object Diagram An object diagram shows a set of the objects and their relationships with each other at a point of time. In a static view, object diagram
Log based recovery: Let us first describe the term transaction log in the context of DBMS. A transaction log is a record in DBMS that remains track of all the transactions of a dat
Explain how the object classes are mapped to tables. Each object class maps to one or more than one tables in the database. The objects in the class may be partitioned horizont
#question benefits and limitations of data models..
Every School has many teachers and many students. Each student is assigned to one school and each teacher works for one school only. Each teacher teaches more than one subject but
Heap files (unordered file) Mostly these files are unordered files. It is the easiest and most basic type. These files having of randomly ordered records. The records will have
Illustrate the term- Abstracting Out Common Behaviour Inheritance is not every time recognised during analysis phase of development, thus it is necessary to re-evaluate object
Database Errors: An error is said to have occurred if the implementation of a command to manipulate the database cannot be successfully finished either due to inconsistent data or
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