Computer Based Transaction Processing Systems
Rujukan: Wilkinson Ch 5
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CHAPTER 4
DATA MANAGEMENT
INTRODUCTION
In fact, data can be defined broadly to include two interrelated components: (1) data models that provide structure to data and (2) data values. Managing a firm’s data resource involves four functions: (1) creation of the records and the repository into which data are stored, (2) maintenance of the repository through activities such as adding new records and updating existing records, (3) retrieval of data stored in the repository, and (4) archival or removal of data.
RELATIONSHIPS OF DATA
DATA ABOUT ENTITIES
An entity is an object, person, or even about which the firm wants to collect and maintain data. Characteristics of an entity are called its attributes. Each attribute stored in the system is a data element.
DATA MODELS
Traditionally, data repositories have primarily been implemented as files. However firms are recognizing data as valued resource and are choosing to store the data in a database.
HIERARCHY OF DATA IN FILE-ORIENTED SYSTEMS
• DATA ELEMENT
Every recorded attribute of an entity is a data element.
1. Field Length. It is the number of contiguous positions required to store a data element.
2. Data Type. The type of a data element refers to the class of data stored in a particular field.
3. Data Value. It is simply the actual data stored in a field.
• RECORD
A record is a series of related data elements of an entity.
• FILE
A file is a collection of data elements that have been organized into records.
FILE-ORIENTED SYSTEMS
In file-oriented systems, each application has a limited number of users who are involved in processing specific types of captured data and employing the outputs for their specialized needs. There are four common types of data files: master files, transaction files, history files, and reference files.
o DESIGN CONSIDERATIONS FOR RECORDS AND FILES
In designing files and records within such as files, several data management questions need to be addressed. The structure of a record is defined by its content, arrangement, modes of data fields, lengths of fields, and keys.
o DOCUMENTING DATA IN FILE-ORIENTED SYSTEMS
A record-level documentation of data is provided by means of the record layout. A record layout shows the respective fields that make up a record and the sequence in which they appear within the record.
o BENEFITS AND LIMITATIONS OF FILE-ORIENTED SYSTEMS
Several data files can serve the purpose of providing necessary information. Such a system is simple and easy to use. File systems can also handle volumes of like transactions efficiently.
HIERARCHY OF DATA IN DATA-BASE SYSTEMS
Data Sets
A data set is a collection of related records, much like a file. However the data sets are appropriately related to other data within a data base.
Data Base
A data base is a totally of data structures that comprise both the data sets and relationships among them.
DATA-BASE SYSTEMS
In a data-base system, data are considered as a shared, central resource for all concerned users and their applications.A data base that spans an entire enterprise is often called a data warehouse and is established to serve the needs of decision makers throughout the organization.
• DOCUMENTING DATA IN DATA-BASE SYSTEMS
Related data elements are grouped together within a data base to represent an entity. By logically grouping data concerning entities, we form the basis of a conceptual data model.
1. Data Dictionary
A data dictionary that focuses on the data elements themselves is needed. It enables users to access and maintain the data.
2. E-R Diagram
An entity-relationship (E-R) diagram represents the conceptual data model by graphically depicting entities and the relationships between them.
• BENEFITS AND RISKS OF DATA-BASE SYSTEMS
One of the greatest benefits of the data-base approach is the ability to provide various managers with the information they need. Besides that there are several risks of data base.
CHOOSING BETWEEN FILE-ORIENTED AND DATA-BASE SYSTEMS
The advantages offered by the data-base system are likely to outweigh associated costs, especially in light of decreasing costs and increased flexibility and processing power of computers.
INTERACTIONS BETWEEN DATA AND PROCESSING
Processing requires procedures. Computer-based procedures called programs are written using a computer language such as C++ or Visual Basic.
DOCUMENTING RELATIONSHIPS BETWEEN DATA AND DATA PROCESSING
Data-flow diagrams (DFD) are a popular documentation tool because they provide a pictorial view of sources of data and entities involved in generating or using new or stored data.
LOGICAL DATA-FLOW DIAGRAM
It shows the flows of data through a transaction processing system without regard to the time period when the data flows or the processing procedure occur.
SUMMARY OF CHAPTER 4 DATA MANAGEMENT
Managing a firm’s data resource involves four major functions:
1. Creation of the records and the repository into which data are stored
2. Maintenance of the repository through activities such as adding new record and updating existing records
3. Retrieval of data stored in the repository and
4. Archival or removal of data.
Data arising from transaction and other sources must be stored and maintained in some sort of a repository. Types of electronic repository are file and data bases. Today most firms developing new systems and applications in business environment choose to use a data base for storing their data. In a data-base environment, data management is accomplished using a data-base management.
Topic 4
Managing a firm’s data resource involves four major functions: (1) creation of the records and the repository into which data are stored.(2)maintenance of repository through activities such as adding new records and updating existing records.(3) retrieval of data stored in the repository, and (4) archival of removal of data.
Data models are used to organize data about entities. The building brick of data models is the data element. An entity is an object, person or event about which the firm wants to collect and maintain data. Characteristic of an entity is attributes, and each attribute stored in the system is a data element.
Data element is an every recorded attribute of an entity. Include customer, inventory item number, and location code. And the element of data element, are (1) field length that’s a no of contiguous positions required to store a data element. (2) data type, (3) data value.
A record is a series of related data elements of an entity. The data organized in the form of records, can be gathered at the time they originate.
A file is a collection of data elements that have been organized into records. A file typically holds data that are similar in nature.
File Oriented Systems.
In file oriented systems, each application has a limited number of users who are involved in processing specific types of captured data and employing the outputs for their specialized needs. In this file-oriented approach to data storage computer, applications maintain their own set of files. Traditional approach focus on individual application.
Most file exist for the purpose of storing data. The following are four common types of data files, these are: master files, transaction files, history files, reference files.
Record key, certain fields within a record, designated as keys, can serve as a way to identify records within a file.
A flag is a type of data element that the systems monitors (rather than the end user). It’s a field within a record which contain a symbol or character used to control the processing of a record.
Logical View versus Physical Storage of Records, in describing information systems, especially data within such systems, two terms are often used : logical and physical.
Designing consideration for records and files.
in designing files and records within such files, several data management questions need to be addressed.
Establishing Record Structure, the structure of a record is defined by its content, arrangement, modes of data field, lengths of fields, and keys.
Documenting Data in File-Oriented Systems, a record level documentation of data is provided by means of the record layout. A record layout shows the respective fields that make-up a record and the sequence in which they appear within the record.
The hierarchy of data in data base systems begins with the data elements. The collection of related data elements of an entity is organized in record-like structures, and the collection of related records is called a data set (is a collection of related records, much like a file), data segment, or a table.
In data base environment, data management is a accomplish using a data-base management systems(DBMS). DBMS is a special type of software that presents the logical view of data resource to users and application programs.
Documenting Data in Data-Base Systems
By logically grouping data concerning entities, we form the basis of a conceptual data model, understanding of a conceptual model of data can be greatly enhanced by two documentation techniques : (1) a data dictionary, to suitable the records layout when data are stored in data bases. (2) E-R Diagram, represent the conceptual data model by graphically depicting entities and the relationship between them.
Benefit and Risk of Data Base Systems
The benefits is the ability to provide various managers with the information they need.
The risks are : the data base approach exacts certain penalties or costs, highly vulnerable.
Maaf Bu, sblmnya saya salah. Saya memasukkan Topic 3 ke topic 4
Di bawah ini saya kirim rangkuman topic 4.
CHAPTER 5
COMPUTER-BASED TRANSACTION PROCESSING
A fundamental task of any accounting information system (AIS) is to process the transactions of reflecting its firm. Transaction processing involves three stages: processing of inputs, processing of data to maintain existing data, and processing of outputs.
Data processing implies the execution of a certain procedure, usually a series of tasks. Where one or more tasks are assigned to computers, we call the system a computer-based system, although some of the tasks may still be manually accomplished. Today’s data processing is not just for processing transactions. Many businesses consider data processing as a key driver of their success, both in terms of cutting costs and creating competitive leverage.
There are also means to capture data, they are:
Input documents
Input document design
Paperless means of data capture
There are some advantages of On-Line Versus Off-Line Data Entry:
• Off-line data entry offers the advantages of economy and productivity
• On-line data entry offers the advantages of timeliness, flexibility, and simplicity.
On-line refers to devices that are directly and continuously connected to a computer system. Transaction data are entered into the computer directly as they occur.
Characteristics of on-line data entry include may include: non existence of source documents (telephone, face to face conversation), input of data using source data automation.
Data processing approaches:
The term data access refers to the method by which data are located and retrieved from the records of a file. The two major data access data sequential access and direct access.
A variety of coding systems have been devised. Four coding systems that use these characters are mnemonic, sequence, block, and group coding systems.
*A fundamental task of any accounting information system (AIS) is to process the transactions of reflecting its firm. Transaction processing involves three stages: processing of inputs, processing of data to maintain existing data, and processing of outputs.
*Data processing implies the execution of a certain procedure, usually a series of tasks. Where one or more tasks are assigned to computers, we call the system a computer-based system, although some of the tasks may still be manually accomplished. Today’s data processing is not just for processing transactions. Many businesses consider data processing as a key driver of their success, both in terms of cutting costs and creating competitive leverage.
*There are also means to capture data:
1. Input documents
2. Input document design
3. Paperless means of data capture
*There are some advantages of On-Line Versus Off-Line Data Entry:
1. Off-line data entry offers the advantages of economy and productivity
2. On-line data entry offers the advantages of timeliness, flexibility, and simplicity.
*Data processing approaches:
The term data access refers to the method by which data are located and retrieved from the records of a file. The two major data access data sequential access and direct access.
* A variety of coding systems have been devised. Four coding systems that use these characters are mnemonic, sequence, block, and group coding systems.
YEHEZKIEL ABISAY
Data can be entered into AIS through any several ways. They can be entered by means of paper (hard-copy) forms or computer terminal screens (soft-copy). They can also directly input from another computer system or input from device such as a telephone keypad or a magnetic card reader such as is used for reading bank cards and credit card.
PROCESSING OF INPUTS – DATA COLLECTION
Off-line Processing of Inputs. In an off-line approach to processing of inputs, transaction data are first captured on source documents. Generally, the source documents pertaining to a group of like transaction \s are gathered into a batch. Then the batched transactions are transcribed into computer-readable form, using an off-line device.
On-line Processing of Inputs. On-line data capture allows immediate processing of inputs to edit data, correct errors, and collect transaction records. On-line data entry permits certain variations in the procedure just describe: (1) Source documents are not always prepared before transaction data are entered, (2) data may entered by means other than keying, (3) data may be entered directly by parties outside the firm who originate transaction, and (4) data may captured and entered from remote than a site where than main computers is located.
DATA MAINTENANCE
At data maintenance stage, the inputs may be processed (1) periodically or immediately, and (2) in sequential or direct fashion.
PROCESSING OF OUTPUTS – INFORMATION GENERATION
Inasmuch as these three processing stages-data collection, data maintenance, and information generation- seem distinct and separate, sometimes they are intertwined in the same application program.
DOCUMENTING PROCESSING
Since data and their processing are invariably intertwined, references to processing tasks appear, such as circles in data-flow diagrams. Similarly, the references to data appear in the documentation of processes. Flowcharts are pictorial representations of transaction processing systems and their flows. Since processing involves flows within a system, flowcharts provide a viable means of documenting system and their processes.
FILE ORGANIZATION AND DATA PROCESSING
File Storage Media. Computerized file storage and management require formalized procedures that must be strictly followed. Identify and location of each element of data must be precisely specified. Each file management step must be carefully programmed. In return for the inconvenience and costless of these requirements, computer-based storage provides important benefits. Large quantities of relevant data are stored very compactly. Data are stored efficiently, since the duplication of records is reduced.
Maintenance of Files. The function known as file maintenance includes the updating activity. Updating or posting, consist of making routine and relatively temporary changes to the data values in stored records. File maintenance also involves three other activities: (1) adding new records to a file, (2) changing fixed or relatively permanent values with records, and (3) deleting record from a file.
DATA PROCESSING APPROACHES
Sequential Access. The Sequential-access method requires each record in a file to be scanned, beginning with the first record in the file. This method is consequently ineffective for finding individual record.
Direct Access. We used the term direct access to denote any method that involves the accessing of desired records in some way other than by an exhaustive search through all the records of a file.
CLASSIFICATION AND CODING
Classification is the act of grouping into classes. Classification plans are designed to achieve specific objectives. For instance, a chart of accounts is a plan that classifies the financial accounts of a firm. Coding is the assignment of symbols, in accordance with a classification plan. Effective codes provide unique and concise identities to the entities and events involved in transactions. Therefore, they ease the entry of data, enhance processing efficiency, speed the retrieval of data from files, and aid the preparation of reports.
Chapter 5
Computer-based transaction processing
Understanding the alternative ways of processing transactions and storing the data should be useful, in at least two respects. First, you will be able to recognize the strengths and limitations of currently installed transactions processing system with which you must cope. Second, you will be able to recommended new or improved processing approaches and storage methods that should fully satisfy the current needs of users and provide the best value.
What do we mean by processing?
Data processing implies the execution of a certain procedure, usually involving a series of tasks. Where one or more tasks are assigned to computers, we call the system a computer-based system, although some of tasks may be still manually accomplished. Computer program designed to achieve specific tasks are called application programs. Application programs can be designed to capture data, process inputs, process data to update or modify existing data (in file or databases), or process data to generate outputs (in the form of reports, listings, or logs).
Means to capture data
Data can be entered into AIS through any of several ways. They can be entered by means of paper (hard-copy) forms computer terminal screens (soft-copy). They can also be directly input from another computer system or input from a device such as telephone keypad or magnetic card reader such as used for reading bank cards and credit cards. When data are entered from individual transactions directly into computer system as they occur, the approach is called on-line data entry. On-line devices are those directly and continuously connected to a computer system. On-line data entry can be combined with of-line data entry in order to completely capture necessary data. Off-line data entry refers to data input through devices not directly connected to a computer. In an off-line approach, transaction data are first captured on input documents, or source documents. The source documents are gathered into a batch, and then the batched transactions are transcribed into computer-readable form, using an off-line device.
Input documents
Input documents are the forms, or source documents, from which data are gathered and input into an AIS. In addition to providing written details of transactions, input documents can do the following:
1. Authorized subsequent transactions
2. Trigger desired action
3. Reflect accountability
4. Provide data for outputs and reference
Input document design
Regardless of the source employed, data entry can be a meticulous and error-prone task for humans. To address this concern, the entry process should be designed in such a way that the manual work is minimized and therefore the opportunity for errors is minimized.
Hard copy documents and forms Well designed documents and forms such as accounting records and source documents are particularly helpful in capturing transaction data. Moreover, well-designed inputs aid the smooth functioning of transaction processing systems, since they clearly document the essential data needed during the processing steps.
Preformatted data-entry screens transactions increasingly are being entered into computerized system via on-line video display terminals and computer monitors. Key principles of form design also apply to screen design. Thus a data entry screen should have a clear purpose and a logical arrangement. In fact, the screen should look very much like the related source document. It should provide clear but concise labels. It might also provide boxes or underscores the denote required characters or words. Since screens are “electronic forms”, they should take advantage of the special features that can aid the humans who use them. That is, well-designed the computer data-entry screens should:
1. Allow, where appropriate, entry of standard data items directly from the system
2. Perform needed computations
3. Respond with clarifying data
4. Move the cursor automatically to places where data elements are to be entered
5. Highlight special areas, error messages. And so on
6. Prompt a HELP function that the user can access
To reduce workload, improve accuracy, and provide memory aids to those who enter data using computer terminals, four widely used approaches in designing data entry screens are employed:
1. Menus
2. Graphical user interface
3. Dialogue prompts
4. Preformatted screens
Processing inputs-Data collection
As we have noted, a firm that has a computer-based system employs an off-line approach, an on-line data entry approach, or mix of the two.
Off-line processing of inputs In an off-line approach to processing of inputs, transaction data are the first captured on source documents. Certain data-such as identification data-are recorded as codes.
On-line processing of inputs On-line data capture allows immediate processing of input to edit data, correct errors and collect transaction records.
Relative advantages of input processing approaches
The off-line data-input approach offers two advantages; economy and productivity. Then, the on-line data input approaches offers greater timeliness, flexibility, and simplicity.
WHAT DO WE MEAN BY PROCESSING?
Data processing implies the execution of certain procedure, usually involving a series of tasks. Where one or more tasks are assigned to computers, we call the system a computer based system, although some of the tasks may still be manually accomplished. Computer programs designed to achieve specific tasks are called application program. Application programs can be designed to capture data, process inputs, and process data to update or modify existing data or process data to generate outputs.
MEANS TO CAPTURE DATA
When data are entered from individual transaction directly into a computer system as they occur, the approach is called on-line data entry. To apply this approach, a firm enters data via online device of some type. On-line devices are those directly and continuously connected to a computer system. Offline data entry refers to data input through devices not directly connected to a computer. In offline approach, transaction data are first captured on input documents, or source documents. The source documents are gathered into a batch, and then the batched transaction are transcribed into computer readable form, using online device.
Input documents
Input documents are the forms, or source documents, from which data are gathered and input to an AIS. In addition to providing written details of transactions, input documents can do the following:
1. Authorize subsequent transaction
2. Trigger desired actions
3. Reflect accountability
4. Provide data for outputs and reference
Input documents design
Hard copy documents and forms several steps should be taken in designing forms. First, we should identify the purpose of the form, its users, and its preparers. Next, we should identify the data elements and their sources. Then these data elements are mapped into a form, giving careful consideration to their logical flow, in order to avoid backtracking. Finally, we should address control issues, such as the sequential numbering of sensitive documents or provision for signatures of preparers.
Preformatted data entry screens well designed computer data entry screens should:
1. Allow, where appropriate, entry of standard data items directly from the system
2. Perform needed computations
3. Respond with clarifying data
4. Move the cursor automatically to places where data elements are to be entered
5. Highlight special areas, error massages, and so on
6. Prompt the user with the question
7. Provide a HELP that the user can access
To reduce workload, improve accuracy, and provide memory aids to those aho entry data using computer terminals. Four widely used approaches in designing data entry screens are employed:
1. Menus. This feature refers to the listings of options by which users can quickly identify and clearly specify desired actions.
2. Graphical user interfaces (GUIs). GUIs allow users to make a selection by pointing to a pictorial view with a device such as a mouse.
3. Dialogue prompts. Question or suggestions displayed by a computer software application to prompt a user for information provide an effective way of gathering information without requiring the user to remember what comes next.
4. Preformatted screens are displayed formats or soft copy forms, which are to be filled in by the relevant users.
PROCESSING OF INPUTS-DATA COLLECTION
Off-line processing of inputs in an off-line approach to processing of inputs, transaction data are first captured on source documents. Certain data such as identification data are recorded as codes. A trained data entry clerk employs a key-to-disk system that converts the data from sales order to a magnetic disk. Before the records on magnetic disk are entered into the computer system for data maintenance, they should be checked for errors and omissions. After the data are keyed, they may be verified by a separate key verification step. Then, as data elements are entered, they may be verified by an edit program.
On-line processing of inputs online data capture allows immediate processing of inputs to edit data, correct errors, and collect transaction records. Online data entry permits certain variations in the procedure just described:
1. Source documents are not always prepared before transaction data are entered.
2. Data may be entered by means other than keying, manually, the data might be entered via voice input devices or light pens.
3. Data may be entered directly by parties outside the firm who originate transactions.
4. Data may be captured and entered from remote sites rather than at site where the main computer is located. Either individual transactions or batches of transactions may be entered via terminals located at remote sites
Relative advantages of input processing approaches the offline data input approach offers two advantages: economy and productivity. The online data input approach offers greater timeliness, flexibility, and simplicity. Transactions are generally entered into the computer system as they arise. Those containing errors can usually be corrected immediately by the entry clerk, so that they do not need to be suspended.
PROCESSING TO UPDATE OR MODIFY EXISTING DATA- DATA MAINTENANCE
At data maintenance stage, the inputs may be processed periodically or immediately, and in sequential or direct fashion. Furthermore, the outputs may be provided periodically or immediately.
PROCESSING OF OUTPUTS-INFORMATION GENERATION
Applications are designed to process outputs, just as they are designed to process inputs or update existing records. Transaction processing applications generate various outputs for a variety of users. These outputs range from documents, such as sales invoices and paychecks, to report, such as financial statements and sales analyses.
Outputs are presented and handled in variety of ways. They may appear in narrative, tabular, or graphical formats. Inasmuch as these three processing stages data collection, data maintenance, and information generation seem distinct and separate, sometimes they are intertwined in the same application program.
DOCUMENTING PROCESSING
Of greatest interest to accountants are system flowcharts diagrams that pictorially portray the physical flows of data through sequential procedures. They picture transaction processing systems (TPS) or major subsystems, highlighting relationships among the elements within TPS. That is, they provide answer to question such as:
1. What inputs are received, and from whom?
2. What outputs are generated, and in what form?
3. What is the next step in the processing sequence?
4. What files and accounting records are affected?
5. Which accounting and organizational controls are employed?
A computer system flowchart, focuses on the computer based portions of transaction processing systems, including computer runs or steps and accesses of online files. The most important use of a computer system flowchart is to document a current procedure or a proposed improved or new procedure.
ALTERNATIVE PROCESSING APPROACHES
Periodic processing approach
Periodic processing involves the processing of data from groups of like transactions at periodic intervals. This approach has traditionally been employed by firms with minimal computer resources, but is also adaptable by firms that have computer based systems. Furthermore, this approach may be combined with either the offline or online entry of data.
1. Sequential updating from batched inputs
To update a master file sequentially within a computer based application, the processing program starts at the beginning master file records. It reads every record in the file, changing data in each record affected by a transaction.
2. Sequential updating after online data entry
Transactions may be processed sequentially after the data are entered by online devices such as terminals. This sequential processing approach provides essentially the same advantages as sequential processing after batched data entry. In addition, it allows errors in the transactions to be corrected and data to be stored within the system at the earliest possible time. On the other hand, it is not quite economical.
3. Direct updating
Where direct updating is used, the transactions do not need to be stored sequentially in the order in which the master file records are sequentially organized. In other words, direct updating with batched transactions allows the sorting step to be eliminated. Also, because they are directly accessible, individual record can be retrieved at any time to determine the status of data. However, direct updating is feasible only if records in the mater files are directly accessible and should be considered when the batches are quite small.
Immediate processing approach
Immediate processing consists of processing each transaction as it arises and is captured. Data from each transaction are entered via an online device and posted immediately and directly to the affected record in one or more master files. Thus the stored data in the master files, which are continuously online, are kept in an up to date status. Immediate processing applications are interactive in that they involve direct interactions between humans and computer based systems.
Enterprise resource planning (ERP)
Enterprise resource planning (ERP) is software with an integrated set of applications for enterprise wide use in functional areas such as finance and accounting, human resource management, and manufacturing and logistics. ERP systems permit an integration of data and applications enterprise wide. Both financial and non financial data can be integrated. The system also facilitates access to data that are within the firm but outside the ERP system.
DATA PROCESSING APPROACHES
The term data access refers to the method by which data are located and retrieved from the records of a file.
The sequential access
The sequential access method requires each record in a file to be scanned, beginning with the first record in the file.
The direct access
The term direct access involves the accessing of desired records in some way other than by an exhaustive search through all the records of a file.
1. The indexed sequential file
This type of file combines a sequential arrangement of records with an index that cross references the primary key values of the records. The index enables individual records to be retrieved quickly, while the file retains the benefits of sequential processing.
2. Randomizing
Randomizing is an accessing procedure in which computations are preformatted to generate addresses of individual records. When the records of a file are located throughput a direct access storage medium by means of randomizing procedure.
CLASSIFICATION AND CODING OF TRANSACTION DATA
Classification is the act of grouping into classes such as classes of data. Coding is the assignment of symbols, such as letters and numbers, in accordance with a classification plan.
Attribute of codes
A coding system that supports a firm’s classification plan should:
1.Uniquely identify objects such as particular customers and sales
2.Be as concise and simple as possible, in order to aid the memory of users and minimize the cost of using and maintaining it
3. Allow for expected growth, so that it will not need to be changed in the foreseeable future.
4. Be standardized throughout all functions and levels within a firm, so tthat porting systems can be fully integrated
Chapter 5
Computer-Based Transaction Processing
Data processing implies the execution of certain procedure, usually involving a series of tasks.
There are two approaches in inputting transaction data:
1) Off-line input: data are captured on source documents in batches, transcribed by off-line devices into computer-readable form, and then entered for processing.
2) On-line input: data from individual transactions are entered directly into computer system as they occur.
File maintenance involves the activities of updating, adding new records to a file, changing fixed or relatively permanent values within records, and deleting records from a file. The approaches to computer-based transaction processing are periodic processing (provides efficient processing and batch total controls) and immediate processing (provides up-to-date records that are readily accessible to users). Data processing can be integrated across many applications and functions with the implementation of an enterprise resource planning (ERP) system.
Chapter 5
Computer-based transaction processing
!. Processing
Data processing implies the execution of a certain procedure, usually involving a series of tasks. Where one or more tasks are assigned to computers, we call the system a computer-based system, although some of tasks may be still manually accomplished. Computer program designed to achieve specific tasks are called application programs. Application programs can be designed to capture data, process inputs, process data to update or modify existing data (in file or databases), or process data to generate outputs (in the form of reports, listings, or logs).
2. Capture Data
Data can be entered into AIS through any of several ways. They can be entered by means of paper (hard-copy) forms computer terminal screens (soft-copy). They can also be directly input from another computer system or input from a device such as telephone keypad or magnetic card reader such as used for reading bank cards and credit cards. When data are entered from individual transactions directly into computer system as they occur, the approach is called on-line data entry. On-line devices are those directly and continuously connected to a computer system. On-line data entry can be combined with of-line data entry in order to completely capture necessary data. Off-line data entry refers to data input through devices not directly connected to a computer. In an off-line approach, transaction data are first captured on input documents, or source documents. The source documents are gathered into a batch, and then the batched transactions are transcribed into computer-readable form, using an off-line device.
3. Input documents :
1. Authorized subsequent transactions
2. Trigger desired action
3. Reflect accountability
4. Provide data for outputs and reference
4. Input documents design
Hard copy documents and forms several steps should be taken in designing forms. First, we should identify the purpose of the form, its users, and its preparers. Next, we should identify the data elements and their sources. Then these data elements are mapped into a form, giving careful consideration to their logical flow, in order to avoid backtracking. Finally, we should address control issues, such as the sequential numbering of sensitive documents or provision for signatures of preparers.
5. Processing inputs-Data collection
As we have noted, a firm that has a computer-based system employs an off-line approach, an on-line data entry approach, or mix of the two.
6. Off-line processing of inputs In an off-line approach to processing of inputs, transaction data are the first captured on source documents. Certain data-such as identification data-are recorded as codes.
7. On-line processing of inputs On-line data capture allows immediate processing of input to edit data, correct errors and collect transaction records.
Relative advantages of input processing approaches
The off-line data-input approach offers two advantages; economy and productivity. Then, the on-line data input approaches offers greater timeliness, flexibility, and simplicity.
8. Classification and Coding of Transaction Data
Classification is the act of grouping into classes such as classes of data. Coding is the assignment of symbols, such as letters and numbers, in accordance with a classification plan.
Attribute of codes
A coding system that supports a firm’s classification plan should:
1.Uniquely identify objects such as particular customers and sales
2.Be as concise and simple as possible, in order to aid the memory of users and minimize the cost of using and maintaining it
3. Allow for expected growth, so that it will not need to be changed in the foreseeable future.
4. Be standardized throughout all functions and levels within a firm, so tthat porting systems can be fully integrated
Chapter 5
COMPUTER-BASED DATA PROCESSING
Understanding the alternative ways of processing transactions and storing the data should be useful, in at least two respects.
I. PROCESSING
Data processing implies the execution of a certain
Vprocedure, usually involving a series of tasks. Where one or more tasks are assigned to computers, we call the system a computer-based system, although some of tasks may be still manually accomplished. Computer program designed to achieve specific tasks are called application programs.
Application programs can be designed to capture data, IV. process inputs, process data to update or modify existing data (in file or databases), or process data to generate outputs (in the form of reports, listings, or logs).
II. CAPTURE DATA
Data can be entered into AIS through any of several ways. They can be entered by means of paper (hard-copy) forms computer terminal screens (soft-copy). They can also be directly input from another computer system or input from a device such as telephone keypad or magnetic card reader such as used for reading bank cards and credit cards. When data are entered from individual transactions directly into computer system as they occur, the approach is called on-line data entry. On-line devices are those directly and continuously connected to a computer system. On-line data entry can be combined with of-line data entry in order to completely capture necessary data. Off-line data entry refers to data input through devices not directly connected to a computer. In an off-line approach, transaction data are first captured on input documents, or source documents. The source documents are gathered into a batch, and then the batched transactions are transcribed into computer-readable form, using an off-line device.
III. INPUT DATA DOCUMENTS
Hard copy documents and forms several steps should be taken in designing forms. First, we should identify the purpose of the form, its users, and its preparers. Next, we should identify the data elements and their sources. Then these data elements are mapped into a form, giving careful consideration to their logical flow, in order to avoid backtracking. Finally, we should address control issues, such as the sequential numbering of sensitive documents or provision for signatures of preparers.
Preformatted data entry screens well designed computer data entry screens should:
1. Allow, where appropriate, entry of standard data items directly from the system
2. Perform needed computations
3. Respond with clarifying data
4. Move the cursor automatically to places where data elements are to be entered
5. Highlight special areas, error massages, and so on
6. Prompt the user with the question
7. Provide a HELP that the user can access
To reduce workload, improve accuracy, and provide memory aids to those aho entry data using computer terminals. Four widely used approaches in designing data entry screens are employed:
1. Menus. This feature refers to the listings of options by which users can quickly identify and clearly specify desired actions.
2. Graphical user interfaces (GUIs). GUIs allow users to make a selection by pointing to a pictorial view with a device such as a mouse.
3. Dialogue prompts. Question or suggestions displayed by a computer software application to prompt a user for information provide an effective way of gathering information without requiring the user to remember what comes next.
4. Preformatted screens are displayed formats or soft copy forms, which are to be filled in by the relevant users.
To reduce workload, improve accuracy, and provide memory aids to those who enter data using computer terminals, four widely used approaches in designing data entry screens are employed:
1. Menus
2. Graphical user interface
3. Dialogue prompts
4. Preformatted screens
IV. PROCESSING INPUTS-DATA COLLECTION
As we have noted, a firm that has a computer-based system employs an off-line approach, an on-line data entry approach, or mix of the two.
V. OFF-LINE PROCESSING
Off-line processing of inputs In an off-line approach to processing of inputs, transaction data are the first captured on source documents. Certain data-such as identification data-are recorded as codes.
The off-line data-input approach offers two advantages; economy and productivity. Then, the on-line data input approaches offers greater timeliness, flexibility, and simplicity.
VI. ON-LINE PROCESSING
On-line processing of inputs On-line data capture allows immediate processing of input to edit data, correct errors and collect transaction records.
Relative advantages of input processing approaches