Database Management System
A Database Management System (DBMS) is a software that allows users to create, retrieve, update, and manage data in a database. It provides an interface for users to interact with the database, and handles tasks such as data storage, retrieval, and security. DBMSs are essential for organizing and maintaining large volumes of data efficiently.
8 Key excerpts on "Database Management System"
eBook - ePubBig Data Computing
A Guide for Business and Technology Managers
- Vivek Kale(Author)
- 2016(Publication Date)
- Chapman and Hall/CRC(Publisher)
...It allows data sharing at a finer resolution, locking only individual data elements during write operations. 8. Without database oversight, data inconsistencies can arise when a long process terminates with an error. The DBMS rejects a transaction that does not complete, with the state of the database remaining as though the transaction had never started. Because the DBMS handles recovery, individual applications need not deal with failed transactions. 9. Without databases, variations in the physical data representation can cause many problems. Database enables programs to be concerned with manipulating the application objects (e.g., persons, tasks, hours, and accounts), not with storage details. 2.1.2 Defining a Database Management System A database is a collection of related data with some inherent meaning and a DBMS is a computerized system that enables users to create and maintain a database. The DBMS is a general-purpose software system that facilitates the processes of defining, creating, manipulating, and sharing databases among various users and appli-cations. where, Defining a database involves specifying the data types, structures, and constraints of the data to be stored in the database. The database definition or descriptive information is also stored by the DBMS in the form of a database catalog or dictionary; it is called metadata. Creating the database is the process of storing the data on some storage medium that is controlled by the DBMS. Manipulating a database includes functions such as querying the database to retrieve specific data, updating the database to reflect changes in the world, and generating reports from the data. Sharing a database allows multiple users and programs to access the database simultaneously. DBMS also provides for querying, protecting, and maintenance of the database. A query typically causes some data to be retrieved; a transaction may cause some data to be read, and some data to be written into the database...
eBook - ePubDigital Business
in The Digital Age
- Jens Christensen(Author)
- 2015(Publication Date)
- Books on Demand(Publisher)
...Each business function developed their own systems and data files. As this process went on for years and even decades, the organization ended up by having hundreds of applications and multiple standards, which were very difficult to maintain and manage. The result was data redundancy (duplicate data in many files and stored in different applications) and inconsistency (different values of the same attribute), and an inability to share data among applications. Under such conditions, companies and organization could not create Enterprise Resource Planning (ERP), Supply Chain Management (SCM), and Customer Relationship Management (CRM) systems that integrate data from different sources, nor could they share information or deliver quick reports for management decision making. A database is the first and necessary solution to the problems of such a spaghetti-like compilation of applications and their files. Serving many applications, a database centralizes data and controls for redundant data. A Database Management System (DBMS) is a piece of software that interacts with users, applications, and the database itself to capture, organize, store and analyze data. The DBMS makes the database available for user questioning and reporting. The most typical type of DBMS today for PCs as well as for larger computers is the relational DBMS. Relational databases represent data as two-dimensional tables, called relations. 350 Each table contains data on an entity and its attributes (for instance, a supplier and the part he supplies, respectively). If two tables share a common data element, they can be combined to respond to user requests...
eBook - ePubInformation Systems
What Every Business Student Needs to Know, Second Edition
- Efrem G. Mallach(Author)
- 2020(Publication Date)
- CRC Press(Publisher)
...Accessing data in a database doesn’t have to be, though. Software packages can manage databases so you don’t have to deal with the details. Such packages are called Database Management Systems. DBMS are a type of system software. They are above the operating system, below users and their applications. Applications access databases through a DBMS, as shown in Figure 5.19. It’s based on Figure 4.3, which shows where software fits in the overall scheme of a system. The DBMS accesses data via the OS, which coordinates access to storage hardware as a shared resource. FIGURE 5.19 Application access to data via a DBMS. Databases include metadata as well as data. Metadata means “data about data.” DBMS access data via metadata. Metadata includes the name of a data element, so users and applications can refer to it; describes its format, such as a photo or a decimal number; and tells the DBMS where it’s stored. Metadata may also include access control information: who may access a data item and what each such person may do with it. An application that needs data sends a message to the DBMS saying what it requires, often using Structured Query Language (SQL, sometimes pronounced “sequel”). A SQL request for names and email addresses of Finance majors with cumulative grade point averages of at least 3.0, with the data in a table named STUDENT, could be written: SELECT NAME, EMAIL FROM STUDENT WHERE MAJOR='FINANCE' AND GPA >=3 The DBMS sends back the (name, email) pairs that meet these criteria. SQL can match keys to find information that is stored across more than one table. To get names and email addresses of MIS301 students, where the REGISTRATION table has student IDs but not their names, one could write: SELECT NAME, EMAIL FROM STUDENT WHERE REGISTRATION.COURSE='MIS301' AND STUDENT.ID=REGISTRATION.ID Simple SQL as in these examples is not difficult to learn, but mastering it takes time and effort. Figure 5.20 shows a user accessing a database...
eBook - ePubBioinformatics
Genes, Proteins and Computers
- Christine Orengo, David Jones, Janet Thornton, Christine Orengo, David Jones, Janet Thornton(Authors)
- 2003(Publication Date)
- Taylor & Francis(Publisher)
...Programs now access data in a shared, integrated database by using the services of a DBMS, which is able to ensure data is shared, integrated and consistent. It might be imagined from the above that having data managed by a DBMS rather than using ordinary files is always advantageous. Indeed, many scientists use a DBMS as though the very fact of having data in a ‘real’ database gives benefits. In fact there are disadvantages in using a DBMS including the following. • A DBMS is expensive. This can include the cost of purchasing the DBMS software, but equally importantly a DBMS is a large piece of software which requires more computer resources such as memory than conventional programs accessing files. File-based access to data does not incur these costs. • DBMSs are complex. If a scientist writing a Perl program to access a file finds the program is not working as expected, there is every chance that the source of the problem can be discovered and corrected. If the same program is using a DBMS, there are many areas of the DBMS’s operation which are complex and can only be corrected with specialist knowledge of the DBMS. • Access to data by a DBMS may be slow. The DBMS software is potentially carrying out a great deal of work to enable access to data reliably by many different programs concurrently and there is an inevitable overhead associated with this. A skilled programmer will always be able to write a program accessing file-based data more quickly. Figure 17.1 File-based v DBMS-based data In summary, the advantages of a DBMS are that it provides shared, integrated access to data, with the ability to modify the types and formats of stored data for the needs of new applications, while allowing existing applications to continue working without modification...
eBook - ePub- James P. Neelankavil(Author)
- 2015(Publication Date)
- Routledge(Publisher)
...A database includes all data, regardless of form, found within the organization. The database and computerized data processor combine to create value by converting data inputs into information. A database is part of an overall management information system. An MIS is an information system that facilitates management control by producing structured, summarized reports on a regular basis. In other words, an MIS is the design and use of effective information systems in business. An integrated information system implies centralized, coordinated information planning and control activities through decentralized information-processing activities. Decentralization makes it possible for information to be processed through data collection, coding, and data conversion. Many users may be linked to a single database. Database design involves the definition, classification, selection, and coding of the data elements to be stored. Databases can be internal or external. Internal databases are developed by companies to assist them in their information needs. Internal databases are company specific and therefore can be used for various activities within the firm. External databases, organized by research suppliers and governments, form a strong base of secondary sources. Some of these external databases, especially from the government and other international organizations, are available at no cost. In contrast, private research companies charge a fee for the use of their databases. C HAPTER R EVIEW 1. What is a database? 2. What is a management information system? 3. How is a database designed? 4. What are the types of databases? 5. How are databases used? 6. Identify and explain some of the frequently used databases. 7. How is an MIS developed? 8. What are the various parts of an MIS? 9. What are the uses of an MIS? 10. What are some of the problems associated with the development of international databases? N OTES 1. Kenneth C...
eBook - ePub- Rob Huddleston(Author)
- 2010(Publication Date)
- Visual(Publisher)
...Chapter 13: Adding Information from a Database Creating a dynamic site gives you the ability to allow your site to interact with a database. Databases are used to store information, which your site can then both display and manipulate. Understanding Relational Databases Create a Database Create a Table Populate the Table with Data Connect PHP to the Database Display the Contents of a Table on a Web Page Search the Database Insert New Data into a Table with PHP Understanding Relational Databases A database, in the simplest terms, is a structured collection of information, or records. Computer databases can be used to store massive amounts of information in a format that makes it easy to sort and find specific data points. Early databases were first developed in the years following World War II. In the 1970s, a new model was proposed that more efficient data storage would be possible if databases were created as a series of related tables. Today, almost every major database system on the market follows this relational database model. Database Management Systems A computer program that stores data is technically called a Database Management System, or DBMS. Many hundreds of DBMS systems are available today, and Web developers mostly rely on one of three systems for their work: Microsoft SQL Server, MySQL, and Oracle. Each has advantages and disadvantages. Due to its close relationship with PHP and its inclusion in the WAMP and MAMP installers, this book looks at MySQL. Relational Databases A relational database is one that stores its information in a collection of tables. Each table stores data about one specific topic. For example, in a database with product ordering information, the details about the products would be in a table, and the details about the customers would be kept separate in a different table...
eBook - ePub- Renata Tesch(Author)
- 2013(Publication Date)
- Routledge(Publisher)
...As data base managers became more popular, software producers added some calculation capacities (a facility on which spreadsheets are based), stretched the size limits on individual entries, as well as the entire data base, allowed different databases to be connected with each other, and provided means by which the user could customize the data base manager. Today hundreds of data base managers are commercially available, and the most powerful of them can be used to handle the entire record keeping of a large business, service agency, or academic institution. Data base managers are now so diverse that it is just about impossible to say anything about them as a group that is true for all of them. There will always be a program that is the exception. Some are no longer called data base managers, because they are meant for special applications. Mail mergers, note takers, text retrievers, all are based on the original data base manager notion and are variations or outgrowths of them. In this chapter, we will provide a rudimentary description of the data base manager concept, and familiarize you sufficiently with the terminology and basic principles so you can judge whether your research work would be facilitated by a data base manager. Basic Principles and Original Structure The basic functions of data base managers are to store information, to modify (add, update, delete) that information, to sort it, and to search/select/retrieve it. Data are entered directly into the data base manager, although by now most of them also import data from other sources (often rather cumbersomely). The basic data unit is the ‘character’, i.e., anything, whether numeric or textual, can be stored and retrieved. In the beginning, all data base managers were structured. This means that they had ‘boxes’, so to speak, into which the user placed information items. The vocabulary used to describe these boxes is fairly standard: they are called ‘fields’...
- Robert C. Hughes(Author)
- 2018(Publication Date)
- Chapman and Hall/CRC(Publisher)
...Human Capital Information stored in a database consists of many changing pieces of data that include employee personal data, pay data, benefit program data, and so on. Nearly all of the information contained in HCMSs is date-sensitive since changes over time need to be kept and maintained in a historical perspective. RELATIONAL Database Management SystemS Since the mid-1980s Relational Database Management Systems (RDMSs) from Major Database Software Vendors such as IBM®, Oracle®, Sybase®, and others have been the predominant Database System used in HCMSs and nearly all other Business Application Databases. This is true whether the system is supplied by a software vendor, custom built in-house, or designed using a combination of these approaches. An Integrated Database Management System (IDMS) is a network-based Database Management System for mainframes and Information Management Systems (IMSs) that uses a hierarchical approach and preceded the introduction of RDMSs in the early 1980s. Edgar Frank Codd invented the relational model for database management while working at IBM. His work formed the basis for RDMSs. RDMS software products such as SQL/DS and later DB2 from IBM and Oracle Database from Oracle Corporation are examples of RDMS software based on Relational Database Theory. In A Relational Model of Data for Large Shared Data Banks (Codd 2003), Codd proposed replacing the hierarchical or navigational structure in then-existing Database Systems with simple tables containing rows and columns. This Two-Dimensional Approach, similar to the same concept used in spreadsheets, lays the cornerstone for modern-day RDMS Table structures. Later we will examine and work with Multidimensional Table Structures found today in Online Analytical Processing (OLAP) Relational Databases. RELATIONAL Database Management System TABLE STRUCTURES In Two-Dimensional RDMS Table Structures, Rows represent Records, and Columns represent Data Fields...
