ME 1403 COMPUTER INTEGRATED MANUFACTURINGTWO MARK QUESTIONS WITH ANSWERS

Unit – IINTRODUCTION

1.What do you mean by CAD? Computer Aided Design (CAD) means the use of a computer to assist in the design of an

individual part or a system. The process usually involves computer graphics to display the designed object on the screen. The CAD system supports the design process at all levels conceptual, preliminary and final design.

2. What do you mean by CAM? Computer Aided Manufacturing (CAM) means the use of a computer to assist in the manufacture

of a part. CAM technology is concerned with three main areas: NC (Numerical Control), process planning and robotics.

3. What do you mean by CIM? CIM is this technology, which holds the capability to accomplish overall automation of the total

system of manufacturing.

4. Define CIM. CIM is the integration of the total manufacturing enterprise through the use of integrated systems

and data communications coupled with new managerial philosophies that improve organizational and personnel efficiency.

CIM is an information structure supporting the free flow of all information resident in the system to any part of the system as needed.

5. What are the elements of CIM? 1. Product design, 2. Planning, 3. Production control 4. Business functions.

6. What are the objectives of CIM? The objectives are as follows:

1. Integrate and control design and manufacturing operations. 2. Develop quality products at competitive prices. 3. Increase sales by controlling product demands. 4. Manage finances.

7. State the major areas of CIM? The Major areas of CIM: 1. Marketing. 2. Engineering design. 3. Research and development. 4. Manufacturing operations. 5. Financial planning.

8. What is role of CIM in manufacturing?

CIM is closely associated with functions manufacturing engineering, such as process planning and numerical control (NC) part programming.

9. What are the benefits of CIM? 1. Quick release of new products

2. Reduced lead times 3. Increased responsiveness and competitiveness. 4. Improved product quality. 5. Shorter delivery times.

6. Shorter production planning

10. Define automation.Automation is generally defined as the process of having machines follow a predetermined

sequence of operations with little or no human labor, using specialized equipment and devices that perform and control manufacturing processes.

11. What are the functions of automated manufacturing systems?Automated manufacturing systems operate in the factory on the physical product. They perform

operations such as processing, assembly, inspection, or material handling, in some cases accomplishing more than one of these operations in the same system.

12. Give the classification of automation.Automated factory systems can be classified into three basic types:

1. Fixed automation2. Programmable automation3. Flexible automation

13. What are the benefits of automation?1. To increase labor productivity2. To reduce labor cost3. To mitigate the effects of labor shortages4. To reduce or eliminate routine natural and clerical tasks5. To improve worker safety.

14. What are the levels of automation and control in manufacturing?1. Machine level (Sensor, actuators, other hardware elements)2. Machine level (Individual machines)3. Cell or system level (Manufacturing system-group of machines)4. Plant level (Production system)5. Enterprise level (Corporate information system)

15. What do you mean by MAP? Manufacturing Automation Protocol is a specialized LAN designed for factory environment. It is

hardware cum software implementable set of rules that facilitate information transfer among networked computers and computer based equipment. MAP is an implementation of the OSI standard.

16. State the major stages of marketing evolution? The evolution of marketing took place in the following main stages:

1. The stage of economic self – sufficiency. 2. The Barter system.3. Money system. 4. The stage of early capitalism.5. Industrial revolution 6. The emergence of marketing.

17. What are the basic features of the modern concept of marketing? The basic features of the modern concept of marketing are:

1. Customer orientation 2. Integrated marketing, and 3. Profitable sales through customer’s satisfaction

18. State the benefits of modern marketing? 1. Consumer needs, wants and desires receive top consideration in all business activities. 2. Greater attention is given to the product planning and development so that the merchandising can become more effective. 3. The supply is adjusted to changing demands of quality, quantity, brand, model etc.,

19. Differentiate selling and Marketing. S. No. Selling Marketing

1. Customer enjoys unique importance Product enjoys the supreme import2. Emphasis on market customer’s need Company oriented selling efforts. 3. Market oriented selling efforts Emphasis on company (sellers) needs.

4.Customer demand determines production supply is adjusted to demand.

Goods are already produced and then sold at profit.

5. Marking aims at long term objectives. Top priority is given to sales volume, rather than profits – increasing sales.

6.Top priority is given to profitable volume of sales and market share at fair prices and reasonable risk.

Selling aims at short term objectives.

20. State the functions of marketing. There are eight functions in marketing.

1. Buying 5. Standardisation and grading 2. Selling 6. Financing 3. Transporting 7. Market information 4. Storage.

21. What are the types of external environment of a firm? a) Micro – environment b) Macro – environment.

22. What do you mean by micro – environment? The micro environment includes its:

i) Suppliers, ii) Intermediaries and iii) Consumers. They are more directly related to the firm and are more controllable than the large, macro forces in the environment.

23. Define marketing strategy.

“Marketing strategy is the basic approach that the business unit will use to attain its goals and which comprises of elaborate decisions (strategies) on largest markets, market positioning and mix marketing expenditure allocation”.

24. What are the methods of market segmentation? 1. Geographic segmentation 2. Demo graphic segmentation 3. Psycho graphic segmentation 4. Buyer behavior segmentation. 5. Volume segmentation.

25. What are the elements of marketing mix? The four elements of marketing mix are:

i) Product, ii) Price, iii) Place (distribution) and (iv) Promotion. These are commonly called as 4P’s of marketing mix.

26. State the major functions of PPC. Major functions of PPC are:

i) Pre- planning ii) Routing iii) Scheduling iv) Despatching v) Controlling

27. State the types of scheduling. The following documents are issued to different departments

1. Job order or work order or shop order 2. Material issue order 3. Tool order. 4. Move order. 5. Final delivery notification.

28. What are the different types of production controls? The different types of production control are:

1. Material control 2. Labor control 3. Cost control.

29. Define unit. When two or more component parts are joined together it becomes a unit, which forms an element

to the product.

30. Define sub – assembly. It is a component of the assembly that enters directly in to the final product. It may be a unit or

combination of units joining them.

31. Define process planning.Process planning is the systematic determination of method or process by which the product is to

be manufactured economically and competitively with in the limits of design of specifications laid down. It consists of devising, selecting and specifying processes, and machine tools

32. What are the functions of process engineering?

1. To determine the blanks sizes of raw materials in processes. 2. To determine the sequence of operations to be performed on each component. 3. To determine the most economical manufacturing process to be used. 4. To determine what parts to be manufactured and what parts to be purchased from outside. 5. To determine, select and initiate the order for purchasing the equipments or machine tools needed to manufacture the product.

33. State the steps in process planning. 1. Analysis of the product print and specifications. 2. Improvement of the specifications. 3. Make or buy decision. 4. Selection of basic manufacturing process. 5.Determine the sequence of operations. 6. Combine the operations. 7. Prepare the list or raw materials. 8. Selection of the machine tools or equipments. 9. Inspection 10. Requirements of tools, gauges. 11. Labor requirements 12. Time standards. 13. Cost of production. 14. Prepare the operation sheet and the route sheet.

34. What are the factors affecting process planning? 1. Size and form of raw materials. 5. Tolerance and surface finish 2. Processing method. 6. Surface finish. 3. Choice of plant layout. 7. Quantity to be manufactured. 4. Capacities of machine tools.

35. What are the functions of financial management?

The financial management being a strategic and key area of management involves variety of functions. From the viewpoint of effective management of finance, the finance functions can be categorized as:

i) Executive finance function. ii) Routine finance function.

36. What are the objectives of financial management?1. Increase in profits 2. Reduction in cost.

Unit – II

Group Technology and Computer Aided Process Planning

1. Define Group Technology. Group Technology (GT) is a manufacturing philosophy in which similar parts are identified and grouped together to take the advantage of their similarities in design and production. Similar parts are arranged in to parts families. Each family possesses similar design and / or manufacturing characteristics. 2. What are the most appropriate conditions in GT?

GT is most appropriately applied under the following conditions: 1. The plant currently uses traditional batch production and a process type layout. 2. The parts can be grouped in to parts families.

3. What are the benefits of GT? 1. GT promotes standardization of tooling, fixturing, and setups. 2. Setup times are reduced, resulting in lower manufacturing lead times. 3. Worker satisfaction usually improves when workers collaborate in a GT cell. 4. Material handling is reduced because parts are moved with in a machine cell rather than

within the entire factory. 5. Process planning and production scheduling are simplified. 6. Higher quality work is accomplished using group technology.

4. What are the three method of GT? The three methods are:

1. Visual inspection 2. Production Flow Analysis (PFA) 3. Classification and coding by examination of design and production data.

5. Define production flow analysis.Production flow analysis is a technique for identifying part families and associated grouping of

machine tools. It does not use a classification and system and part drawing to identify families. Production flow analysis makes the use of information contained on route sheets instead of part drawing.

6. Write down the procedure for production flow analysis. Procedure for production flow analysis can be organized in to four categories.

1. Data collection. 2. Sorting of process routings. 3. PFA chart. 4. Analysis.

7. What are the categories of part classification?

1. System based on part design attributes. 2. System based on manufacturing attributes. 3. System based on both design and manufacturing attributes.

8. Define Coding. The code structures generally consist of numbers, letters or combinations of two. Each specific

compenent of product is assigned a code. The code may pertain less than twelve digit design attributes or less than twelve digit manufacturing attributes. In most advanced system it may pertain thirty digit attributes of both design and manufacturing. 9. Define Decision tree coding.

It is also known as hybrid code. This is most advanced system. It combines both design and manufacturing attributes.

10. What are the six major industrial coding systems? The six major industrial coding systems are: 1. OPITZ system. 2. KK – 3 system. 3. DCLASS system. 4. Multi- class system. 5. CODE system 6. RNC – 6 digits Mono code system.

11. Define Single machine cell. It consists of one machine with necessary fixtures and tooling. This type of cell is suitable to work

parts with attributes that allow them to be processed on turning or milling.

12. Define Flexible manufacturing system. It is the combination of fully automatic processing machines and automated material handling

system.

13. What is cellular manufacturing? Cellular manufacturing is an application of group technology in which dissimilar machines or processes have been aggregated in to cells, each of which is dedicated to the production of a part or product family or a limited group of families.

14. What are the objectives of cellular manufacturing? 1. To shorten manufacturing lead times

2. To reduce work – in – process inventory 3. To improve quality 4. To simplify production scheduling 5. To reduce setup times.

15. What are the types of layouts used in GT cells? The U – shape, Other GT layouts include in – line, loop, and rectangular.

16. What is mean by process planning? Process planning is an important task in discrete part manufacturing. In the production process, there is a sequence of production operations through which the raw material is effectively converted in to finished product. So, there must be a perfect production planning and production design is necessary to complete the product. This process of decision-making is called process planning.

17. What are two stages of process planning? Process planning is carried out in two stages: 1.Process design. Process design is macroscopic decision – making of an overall process route for converting the

raw material in to finished product. 2.Operation design Operation design is microscope decision – making of an individual operations contained in the

process route.

18. Write down the four basic approaches of process planning? There are four basic important approaches to perform the task of process planning. They are:

1. Manual approach 2. Variant approach 3. Generative approach 4. Hybrid approach

19. Write any two advantages of manual approach. 1.This becomes rapidly inefficient and unmanageable when the number of process plans and a revision to those plans increases.

2. It requires large time for planning. 3. Inconsistent plans. 4.This approach always reflects the personal experiences and preferences, prejudices of the

process planner.

20. Define Generative approach. Generative process planners should create a new process plan without the use of any

existing plans. This does not imply that the process planner is automatic. It is an alternative system to variant CAPP. A generative CAPP creates the process plan using systematic procedure rather than retriving and editing the existing plans from a database.

21. What are the stages of generative CAPP system? i) Knowledge base.

ii) Computer comparable part description. iii) Inference engine.

22. Write down any two benefits of CAPP? i) Increase in productivity of process planners. ii) Production rationalization and standardization iii) Improved legibility iv) Integrated with other application. v) Effective inventories vi) Reduced lead-time. vii) Updation and Access. viii) Other improvements. ix) Response.

23. Write down any four advantages of CAPP. 1. It reduces process planning and production lead-time. 2. It has faster response to engineering changes, this will lead to revise or create new plans

according to technology development. 3. It access to up–to-date information in a central database.

4. It improves cost estimating procedures and reduces the calculation error.

Unit – III

Shop Floor Control and Introduction to FMS

1. What are the phases of shop floor control? A typical shop floor control system consists of three phases:

1. Order release. 2. Order scheduling. 3. Order progress. 4.

2. What are the contents of shop pocket? 1. The route sheet, which documents the process plan for the item to be produced.

2. Material requisitions to draw the necessary raw materials from inventory. 3. Job cards or other means to report direct labor time developed to the order and to indicate progress of the order through the factory.

3. What are the problems solved by order scheduling? The order scheduling module in shop floor control is intended to solve two problems in

production control : 1) Machine loading and 2) Job sequencing.

4. Name some dispatching rules in plant. 1. First – come – first serve.

2. Earliest due date. 3. Shortest processing time.

4. Least slack time.5. Critical ratio.

5. What are the reasons for shop floor scheduling? a) Jobs shops have to produce products against customer orders for which delivery dates have to be promised. b) Production lots tend to be quite small and may require numerous machine change – over. c) Possibility of assigning and reassigning workers and machines to many different orders due to flexibility.

6. What are the types of scheduling techniques? Types of scheduling techniques 1. Forward Scheduling2. Backward Scheduling

7. What are the stages in scheduling? 1. Loading 2. Dispatching

8. Name the types of Gantt chart? a) Finite loading b) Infinite loading

9. What are the types of Gantt chart? Gantt charts are used to display graphically the workloads on each work center. There

are two types of Gant charts, i) Gantt load chart and ii) Gantt scheduling chart or progress chart.

10. What do you mean by FDC system? The Factory Data Collection (FDC) system consists of the various paper documents,

terminals, and automated devices located through out the plant for collecting data on shop floor operations plus the means of compiling and processing the data usually by computer.

11. What are the types of FDC system? 1. On – Line Versus Batch systems. 2. Data Input Techniques.

12. State the technologies available for automatic identification system.The technologies available for use in automatic identification systems.

1. Bar codes. 2. Magnetic stripe. 3. Machine vision. 4. Radio frequency systems. 5. Optical character recognition

13. What do you mean by OCR? Optical character Recognition (OCR) techniques refer to a specially designed alphanumeric character set that is machine readable by an optical sensor device. The substantial benefit offered by OCR technology is that the characters and associated text can be read by human beings as well as machines.

14. What are the types of bar code readers? Bar code readers in a variety of configurations; some require a human being a operate

them and others are stand – alone automatic units. They are usually classified as contact or non contact readers.

15. What do you mean by data acquisition system? A Data Acquisition System (DAS) is a computer used to automatically collect data from a

process or piece of equipment. Data acquisition systems either perform and analysis of the data or transmit the data to another computer for processing and analysis.

16. What do you mean by data logger? A data logger is a system that is sometimes compared with a data acquisition system. A

data logger is a device that automatically collects and stores data for later off – line (batch) analysis. No data capability is available on the data logger.

17. What do you mean by multilevel scanning? In multilevel scanning, there are two (or more) levels of process scanning performed by the

computer system, a high – level scan and a low – level scan. During normal operation of the

process, only the high -level scan is performed . In this monitoring procedure, only the key variables and status data are scanned.

18. Name some automated data collection system. 1. Bar code. 2. Optical Character Recognition 3. Machine vision system.

19. Name the cameras used in vision system. Cameras in vision systems are either vidicon similar to a commercial TV camera, or CCD

(Charge – Coupled Device). A third type is the CCPD (Charge – Coupled Photo – Diode) image sensor. Both CCD and CCPD cameras are based on solid-state electronics.

20. What are the tasks carried out by vision system? Vision systems can carry out a variety of tasks in several general categories: a) Gauging, b) Verifying, c) Identifying d) Recognizing, e) Locating, f) Detecting flaws, and g) Multimedia

integrating

21. Name the types of voice recognition system? Voice recognition (VR) is of two types

i) Speaker dependent ii) Speaker independent.

22. What do you mean by FMS? A FMS is a group NC machine tools can randomly process a group of parts, having

automated material handling and central computer control to dynamically balance resource utilization so that the system can adopt automatically to change in part production, mixes and levels of output.

23. What are the types of flexibility? a) Machine flexibility b) Process flexibility c) Product flexibility d) Routing flexibility e) Volume flexibility f) Expansion flexibility g) Operation flexibility h) Production flexibility \

24. State the classifications of FMS. The FMS can be classified based on:

1. Kinds of Operation 2. Number of machines. 3. Flexibility level.

25. Differentiate between batch mode and flexible mode.

Batch Mode Flexible Mode

1. The Machine processes parts of a single style in specified lot sizes.

1.The system satisfies the following flexibility test. a) Processing different part style.

2. It is changed over to process a batch b) Responding to changes in production schedule. c) New parts are introduced. 2. Error recovery cannot be satisfied.

26. Differentiate between FMS and FMC.

S. No. FMS FMC

1. It has four or more machines. It has two or three machines.

2.It includes non processing Workstation.

It does not include non processing workstations

3.Computer control system is larger and more sophisticated.

Computer control system is smaller

27. What are the components of FMS? The components of FMS are listed below:

1. Work stations 2. Material handling and storage system. 3. Computer control system. 4. Human resources. 28. What are the different categories of FMS layout?

1. In – lint layout 2. Loop layout 3. Ladder layout 4. Open field layout 5. Robot – centered cell.

29. State the applications of FMS. 1. All types of machining operations. 2. Assembly works 3. Sheet metal press – working 4. Forcing 5. Welding 6. Surface – treatment. 7. Inspections and Testing.

30. State the benefits of FMS. To provide flexible manufacturing facilities for a family of work pieces

It reduces both direct and indirect labor cost; machines and material handling systems associated with FMS are unmanned and are under the control of a supervisory computer. It can maximize the combination of operation at a single location. FMS minimizes the requirement of tooling as in most of the cases specialized tooling is software. It provides better and more consistent quality products.

Unit – IV

CIM Implementation and Data Communication

1. What are the four dimensions of evaluating performance? 1. Cost 2. Delivery. 3. Tight specification. 4. Flexibility.

2. What are the activities of computer integrated production system? 1.Sales and Marketing 2. Forecasting 3. Production planning (Aggregate production planning) 4. Design planning 5. Master scheduling 6. Engineering and Manufacturing database 7. Process planning 8. Material Requirement Planning (MRP) 9. Capacity planning .

3. Define capacity planning It is concerned with determining the labor and equipment resources needed to meet the production schedule. This may lead to the revision of master production schedule. The function of capacity planning in the over all system is shown in figure 4. The master schedule is transformed in to material and component requirements using MRP. Then these requirements are compared with available plant capacity. If the schedule is not suitable with the capacity, adjustments must be made either in the master schedule or in plant capacity.

4. Define IDEF. IDEF (for Integrated Definition) is a group of modeling methods that can be used to describe operations in an enterprise. IDEF was created by the united states Air Force and is now being developed by knowledge based systems.

5. Name the most commonly used IDEF models. IDEFO through IDEF4 are the methods most commonly used.

6. Explain the concept of CIM. The CIM concept is that all of the firm’s operation related to production are incorporated in an integrated computer system to assist, augment and automate the operations.

IDEF0 IDEF1IDEFIX IDEF2IDEF3IDEF4

Function Information Modeling Data Modeling Simulation Model Design Process Description Capture Object – Oriented Design

7. What do you mean by CIM – OSA model? The CIM – OSA model provides a mechanism for preparing and structuring the planning and control activities of these functions and for charging structured information between them. With the help of a computer, a planner is able to consult the CIM – OSA reference architecture to construct an operating environment for his application.

8. What do you mean by CIM architecture? CIM architecture is a frame work that provides a structure of computer hardware and software with appropriate interface for computer systems in manufacturing enterprises to integrate information and business processes.

9. Define product data management. Product Data Management (PDM) is a category of computer software used to control data related to products. PDM creates and manages relations between sets of data that define a product, and store those relationships in database. It is an important tool in product life cycle management.

10. What are the necessities of doing PDM? 1. Reduce engineering costs by least 10% 2. Reduce the product development cycle by at least 20% 3. Reduce engineering change handling time by at least 30 % 4. Reduce the number of engineering changes by at least 40 %

11. What are the uses of PDM? PDM is mainly used by engineers to manage their work and to access data of others in the

design team. It is used in most industries but is used to an advanced level in Automotive and Aerospace.

12. State the advantage of PDM. 1. Protect project files with simply security; 2. Accelerate return on investment with easy setup; 3. Spend less time organizing and tracking design data ; 4. Improve productivity through reuse of product design data; 5. Enhance collaboration.

13. Name some CIM Hardware. i) Manufacturing equipments It includes,

1. Workstations/ process stations. 2. Cells 3. DMC / FMS systems.

ii) Computer system It includes,

1. Computer 2. Controls 3. CAD/CAM systems

iii) Office equipments It includes,

1. Computers / terminals 2. Plotters / Printers etc.,

14. Name some CIM implementation software. i) Management ii) Sales programme. iii) Marketing programmeiv) Finance programme v) Database management programme. vi) Design programme.

15. What do you mean by LAN? A Local Area Network (LAN) is an arrangement of hardware and software that permits

logically related devices to communicate with each other over distances up to 20 miles. In the CIM environment, these devices may be machining centers.

16. What are the elements of LAN? i) Nodes ii) Network communication cards (adaptor cards) iii) Network software iv) Transmission media (cabling) (v) Server (PC or dedicated) (vi) Peripherals

17. Name some LAN architecture. 1. The “bus” or “open ring” structure 2. The “start” or “hierarchical” structure 3. The “loop” or “ring” structure

18. Name various topologies in network. i) Star network ii) Ring network iii) Bus networks iv) Hybrid network.

Unit – V

Open System and Database for CIM

1. What is OSI model? The OSI model itself is not a network architecture because it does not specify the exact

services and protocols to be used in each layer. It just tells what each layer should do. However, ISO has also produced standards for all the layers, although these are not part of the reference model itself.

2. What is mean by physical layer? The physical layer is concerned with transmitting raw bits over a communication channel.

3. What are the types six layer is OSI model? 1. The physical layer. 2. The data link layer. 3. The network layer. 4. The transport layer. 5. The session layer. 6. The Presentation layer.

7.The application layer.

4. Distinguish between MAP and TOP protocols Layer MAP TOP LAYER 7 - APPLICATION LAYER 6 - PRESENTATION LAYER 5 - SESSION LAYER 4 - TRANSPORT LAYER 3 - NETWORK LAYER 2 - DATALINK LAYER 1 - PHYSICAL

MAP NUL ISO 8327 ISO 8073 /CLASS 4 ISO 8473 IEEE 802.2 IEEE 802.2

ISO FTAM 8571 NULL ISO 8327 ISO 8073 /CLASS 4 ISO 802.2 ISO 802.2 ISO 802.4

5. Write down the principles of database processing?

The first major benefit of using database management systems is that every time a user alters data in the data base all other users receive the updated, i.e., the latest version, or correct data.(Note that in this interpretation a “user” is not only or not necessarily a human being sitting in front of a terminal and retrieving sales figures, but can be a machine controller asking for a program, or another computer and accessing the database).

6. What are the important features of database management? The most important features are: 1. The relational. 2. The hierarchical 3. The network 4. The free format. 5. The multi – user, distributed structure.

7. Define data item. A data item is the smallest unit of data with a name; data items may be several bits long.

8. What are the three level of architecture of database system?Divided in to three levels: the external level, the conceptual level, and the internal level.

9. What is mean by external schema? Each external view is described by means of a scheme called an external schema. The

external schema consists of the definition of the logical records and the relationship in the external view. The external schema also contains the method of deriving the objects in the external view from the object in the conceptual view. The objects includes entities, attributes, and relationship. (The terms view, scheme, and schema are sometimes used interchange by when there is no confusion as to what is implied.)

10. Define the term entities. Entities are the basic units in modeling classes of concrete or abstract objects. Entities can

have concrete existence or constitute ideas or concept. Each of the following is an entity: building, room, chair, transaction, course, machine, employee. An entity type or entity set is a group of similar objects of concern to an organization for which it maintains data.

11. Define functional dependency. Give two sets of attributes X and Y, Y is said to be functionally dependent on X if a given

value for each attribute in X uniquely determines the value of the attributes in Y X is called the determinant of the functional dependency (FD) and the FD is denoted as X – Y. The process of identifying functional dependencies and selecting those attributes that should be grouped together in a given record is central to the process of database design.

12. Define the term domain. We define a domain, Di , as a set of values of the same data type.

The domain, Di, a set having “homogeneous” members, is conceptually similar to the data type of concept in programming language. A domain like a data type may be unstructured (atomic) or structured. Domain Di is said to be simple if all its elements are nondecomposible (i.e., atomic). (When we use the term decomposable, we mean is term of the DBMS). In typical DBMSS, atomic domains are general sets, such as the sets of integers, real numbers, character strings, and so on.

13. What is an alternate key? One of the candidate keys is chosen as the primary key; the others are known as alternate

keys. An attribute that forms part of a candidate key of relation is called a prime attribute.

14. What are the three explicit possibilities? All tuples that contains references to the deleted tuple should also be deleted. This may

cause, in turn, the delection of other tuples. This option is referred to as a domino or cascading delection, since one deletion, since one deletion leads to another.

Only tuples that are not referenced by any other tuple can be deleted. A tuple referred by other tuples in the database cannot be deleted. The tuple is deleted. However, to avoid the domino effect, the pertinent foreign key attributes of all referencing tuples are set to null.

15. What are the advantages of DBMS? i) Reduction of redundancies

ii) Shared data. iii) Integrity. iv) Security. v) Conflict resolution. vi) Data independence.

16. What are the advantages of RDBMS? 1. Support for very large databases. 2. Automatic optimization of searching (when possible). 3. RDBMS have a simple view of the database that conforms to much of the data used in business. 4. Standard query language (SQL).

17. What are the disadvantages of RDBMS? 1. Difficult to put file system tree in to tables. 2. Performance will growing number of clients and entries not investigated. 3.Until recently, no support for complex objects such as documents, video, images, spatial or time – series data.( ORDBMS are adding support these). 4.Often poor support for storage of complex objects.(Disassembling the car to park it in the garage). 5. Still no efficient and effective integrated support for things like text searching within fields.

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