Chapter 10 Review Discovering Computers - Student Assignment (Mr. Tri Djoko Wahjono, Ir.,M.Sc)

Discovering Computers

Student Assignment - Chapter 10 Review

Name         : Anneke Dwi Sesarika Rahmanto

Class          : 01PCT

Student ID : 1701316166

Lecture      : Mr. Tri Djoko Wahjono, Ir., M.Sc.

1. What is a Database, and How does a Database interact with data and information?

A database is an organized collection of data. The data are typically organized to model relevant aspects of reality in a way that supports processes requiring this information. For example, modeling the availability of rooms in hotels in a way that supports finding a hotel with vacancies.

Database management systems (DBMSs) are specially designed applications that interact with the user, other applications, and the database itself to capture and analyze data. A general-purpose database management system (DBMS) is a software system designed to allow the definition, creation, querying, update, and administration of databases. Well-known DBMSs include MySQL, PostgreSQL, SQLite, Microsoft SQL Server, Oracle, SAP, dBASE, FoxPro, IBM DB2, LibreOffice Base and FileMaker Pro. A database is not generally portable across different DBMS, but different DBMSs can interoperate by using standards such as SQL and ODBC or JDBC to allow a single application to work with more than one database.

Formally, the term "database" refers to the data itself and supporting data structures.

Databases are created to operate large quantities of information by inputting, storing, retrieving, and managing that information. Databases are set up so that one set of software programs provides all users with access to all the data. A "database management system" (DBMS) is a suite of computer software providing the interface between users and a database or databases. Because they are so closely related, the term "database" when used casually often refers to both a DBMS and the data it manipulates. Outside the world of professional information technology, the term database is sometimes used casually to refer to any collection of data (perhaps a spreadsheet, maybe even a card index).

This article is concerned only with databases where the size and usage requirements necessitate use of a database management system.

The interactions catered for by most existing DBMS fall into four main groups:

• Data definition. Defining new data structures for a database, removing data structures

• Update. Inserting, modifying, and deleting data.

• Retrieval. Obtaining information either for end-user queries and reports or for

• Administration. Registering and monitoring users, enforcing data security, monitoring from the database, modifying the structure of existing data. processing by applications. performance, maintaining data integrity, dealing with concurrency control, and recovering information if the system fails.

A DBMS is responsible for maintaining the integrity and security of stored data, and for recovering information if the system fails. Both a database and its DBMS conform to the principles of a particular database model. "Database system" refers collectively to the database model, database management system, and database. Physically, database servers are dedicated computers that hold the actual databases and run only the DBMS and related software. Database servers are usually multiprocessor computers, with generous memory and RAID disk arrays used for stable storage. RAID is used for recovery of data if any of the disks fails. Hardware database accelerators, connected to one or more servers via a high-speed channel, are also used in large volume transaction processing environments. DBMSs are found at the heart of most database applications. DBMSs may be built around a custom multitasking kernel with built-in networking support, but modern DBMSs typically rely on a standard operating system to provide these functions. Since DBMSs comprise a significant economical market, computer and storage vendors often take into account DBMS requirements in their own development plans. Databases and DBMSs can be categorized according to the database model(s) that they support (such as relational or XML), the type(s) of computer they run on (from a server cluster to a mobile phone), the query language(s) used to access the database (such as SQL or XQuery), and their internal engineering, which affects performance, scalability, resilience, and security.

2. What is Data Integrity, and what are the qualities of valuable information?

Data integrity refers to maintaining and assuring the accuracy and consistency of data over its entire life-cycle, and is a critical aspect to the design, implementation and usage of any system which stores, processes or retrieves data. The term data integrity is broad in scope and may have widely different meanings depending on the specific context - even under the same general umbrella of computing. This article provides only a broad overview of some of the different types and concerns of data integrity.

Data integrity is the opposite of data corruption, which is a form of data loss. The overall intent of any data integrity technique is the same: ensure data is recorded exactly as intended (such as a database correctly rejecting mutually exclusive possibilities,) and upon later retrieval, ensure the data is the same as it was when it was originally recorded. In short, data integrity aims to prevent unintentional changes to information. Data integrity is not to be confused with data security, the discipline of protecting data from unauthorized parties.

Any unintended changes to data as the result of a storage, retrieval or processing operation, including malicious intent, unexpected hardware failure, and human error, is failure of data integrity. If the changes are the result of unauthorized access, it may also be a failure of data security. Depending on the data involved this could manifest itself as benign as a single pixel in an image appearing a different color than was originally recorded, to the loss of vacation pictures or a business-critical database, to even catastrophic loss of human life in a Life-critical system.

3. What is meant by Character, Field, Record, and File?

Data is classified in a hierarchy, with each level of data consisting of one or more items from the lower level. A bit is the smallest unit of data a computer can process. Eight bits grouped together in an unit form a byte, and each byte represents a single character, which can be a number, letter, space, punctuation mark, or other symbol.

A Field is a combination of one or more related characters or bytes and is the smallest unit of data a user accesses.

A Record is a group of related fields.

A Data File is a collection of related records stored on a storage medium such as a hard disk or optical disc.

4. What are file maintenance techniques and validation techniques?

File maintenance refers to the procedures that keep data current. File maintenance procedures include adding records to correct inaccurate data or to update old data with new data, and deleting records when they no longer are needed.
Validation is the process of comparing data with a set of rules or values to find out if the data is correct. Many programs perform a validity check that analyzes data, either as you enter it or after you enter it, to help ensure that it is correct. Types of validity checks include an alphabetic check, a numeric check, a range check, a consistency check, a completeness check, and a check digit.

5. How is a file processing approach different from database approach?

Each department or area within an organization has its own set of data files. The records in one file may not relate to the records in any other file. Two major weaknesses of file processing systems are redundant data (duplicated data) and isolated data. With a database approach, many programs and users share the data in database. The database approach reduces data redundancy, improves data integrity, shares data, permits easier access, and reduces development time. A database, however, can be more complex than a file processing system, requiring special training and more computer memory, storage, and processing power than file processing systems. Data in a database also can be more vulnerable than data in file processing systems.

6. What functions are common to most database management systems?

Database management system - (DBMS) A suite of programs which typically manage large structured sets of persistent data, offering ad hoc query facilities to many users. They are widely used in business applications.

A database management system (DBMS) can be an extremely complex set of software programs that controls the organization, storage and retrieval of data (fields, records and files) in a database. It also controls the security and integrity of the database. The DBMS accepts requests for data from the application program and instructs the operating system to transfer the appropriate data. When a DBMS is used, information systems can be changed much more easily as the organization's information requirements change. New categories of data can be added to the database without disruption to the existing system.

Data security prevents unauthorized users from viewing or updating the database. Using passwords, users are allowed access to the entire database or subsets of the database, called subschemas (pronounced "sub-skeema"). For example, an employee database can contain all the data about an individual employee, but one group of users may be authorized to view only payroll data, while others are allowed access to only work history and medical data.

The DBMS can maintain the integrity of the database by not allowing more than one user to update the same record at the same time. The DBMS can keep duplicate records out of the database; for example, no two customers with the same customer numbers (key fields) can be entered into the database. Query languages and report writers allow users to interactively interrogate the database and analyze its data. If the DBMS provides a way to interactively enter and update the database, as well as interrogate it, this capability allows for managing personal databases. However, it may not leave an audit trail of actions or provide the kinds of controls necessary in a multi-user organization. These controls are only available when a set of application programs are customized for each data entry and updating function.

A business information system is made up of subjects (customers, employees, vendors, etc.) and activities (orders, payments, purchases, etc.). Database design is the process of deciding how to organize this data into record types and how the record types will relate to each other. The DBMS should mirror the organization's data structure and process transactions efficiently.
Organizations may use one kind of DBMS for daily transaction processing and then move the detail onto another computer that uses another DBMS better suited for random inquiries and analysis. Overall systems design decisions are performed by data administrators and systems analysts. Detailed database design is performed by database administrators.The three most common organizations are the hierarchical database, network database and relational database. A database management system may provide one, two or all three methods. Inverted lists and other methods are also used. The most suitable structure depends on the application and on the transaction rate and the number of inquiries that will be made.Database machines are specially designed computers that hold the actual databases and run only the DBMS and related software. Connected to one or more mainframes via a high-speed channel, database machines are used in large volume transaction processing environments. Database machines have a large number of DBMS functions built into the hardware and also provide special techniques for accessing the disks containing the databases, such as using multiple processors concurrently for high-speed searches.The world of information is made up of data, text, pictures and voice. Many DBMSs manage text as well as data, but very few manage both with equal proficiency. Throughout the 1990s, as storage capacities continue to increase, DBMSs will begin to integrate all forms of information. Eventually, it will be common for a database to handle data, text, graphics, voice and video with the same ease as today's systems handle data.

7. What are Characteristics of relational, object-oriented, and multidimensional databases?

This isn’t the first time in recent history that new types of database products have emerged and overcome RDBMS inefficiencies. Back in the 1980s, a class of applications was identified in which RDBMS products ill-handled the data-management needs (especially the generation of RDBMSs available at that time).These applications all needed user-specified data types that varied among different implementations. For example, computer-aided design/computer-aided manufacturing (CAD/CAM) applications had to be capable of specifying data types that related to product drawings, blueprints, and other related factors.Computer-aided software engineering (CASE) needed data types to represent applications and systems, databases, graphical representations of entities and attributes, process and data flows, and other parts of the application-development process.What resulted was object-oriented database management systems (ODBMSs), which eliminated the table-row-column structures of relational databases and instead introduced the concepts of classes and subclasses (or types and subtypes), objects, properties, methods, and the other parts of object-oriented technology directly into the database engine.

Because RDBMS technology wasn’t well-suited to multidimensional analysis, particularly in terms of performance, vendors set out to develop their own structures tuned and optimized for improved performance.If you track happenings in the database management world, you’re probably familiar with the convergence of relational and object-oriented database technology. RDBMS products are being equipped with object-oriented extensions.Arguably, this approach to handling complex data types (objects) has won out over non-
relational products (“pure” ODBMSs), primarily because of the large installed base of relational products and applications running on top of them. Will the same thing happen in the data warehousing world — relational technology overtaking and then overwhelming specialized multidimensional products? Only time will tell.

8. How are Web Databases Accessed?

You can use Access 2010 and Access Services, a new component of SharePoint, to build web
database applications. This helps you:
• Secure and manage access to your data
• Share data throughout an organization, or over the Internet Note A user account is required to use a web database. Anonymous access is not supported.
• Create database applications that don't require Access to use

9. What are the responsibilities of Database Analysts and Administrators?

A database administrator's responsibilities can include the following tasks:
• Installing and upgrading the database server and application tools
• Allocating system storage and planning future storage requirements for the database system
• Modifying the database structure, as necessary, from information given by application developers verbally
• Enrolling users and maintaining system security
• Ensuring compliance with database vendor license agreement
• Controlling and monitoring user access to the database
• Monitoring and optimizing the performance of the database
• Planning for backup and recovery of database information
• Maintaining archived data
• Backing up and restoring databases
• Contacting database vendor for technical support
• Generating various reports by querying from database as per need.