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Database monitoring Systems �A database management system (DBMS), or database program, is software application that permits you to create, access, and manage a database. �DBMSs are accessible for plenty of sizes and species of computers.




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Database management Systems


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Data thesaurus �A data dictionary, sometimes referred to as a repository, has data around each field in those files. �For each document it stores details such together the file name, description, the file’s partnership to other files, and the number of records in the file. �For each field, it shop the field name, description, ar type, ar size, default value, validation rules, and also the field’s connection to various other fields.


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Data dictionary �Because the data dictionary contains details about data, some contact it metadata, meta definition more comprehensive. �It is a crucial backbone come a DBMS therefore only experienced professionals need to update its contents. �It is offered to execute validation checks and limit the form of data that deserve to be entered.


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Data thesaurus �A data dictionary enables users come specify a default value for a field, which is a value that the DBMS initially screens in a field. ◦ Ex. If most students live in Indiana, the default value can read ‘IN’. �The user doesn’t have to kind the default value which help in reduce errors.


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Data dictionary


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File Retrieval and Maintenance �A DBMS provides several tools that allow users and programs to retrieve and maintain data in the database (adding, modifying, and deleting). �To retrieve or select data in a database, friend query it, which is a request for details data indigenous the database. �Users deserve to instruct the DBMS to display, print, or store the results of a query, making it one of the an ext powerful database features.


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Query Language �A questions language consists of simple, English-like statements that enable users to specify the data come display, print, or store. �Each has its very own grammar and vocabulary. �A person without programming experience deserve to learn a ask language in a brief time. �Most queries are supplied to retrieve data. �Some DBMSs provide wizards to overview


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Query by example �Most DBMSs encompass query by example (QBE), a attribute that has actually a graphical user interface to help users with retrieving data.


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Form �A form, sometimes called a data entrance form, is a home window on the screen that provides locations for start or modifying data in a database. �Well-designed creates should validate data as it is entered. �A kind that sends entered data across a network or the internet is referred to as an eform, quick for electronic form. �E-forms generally use a means to for sure the data while it is transported across the network.


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Form


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Report Generator �A report generator, also called a report writer, enables users to design a report ~ above the screen, retrieve data right into the report design, and then display screen or publish the report. �Unlike a form, report generators can only retrieve data. �Report generators enable you to format the page and some enable you to create a report together a internet page.


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Report Generator


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Data security �A DBMS provides method to ensure that just authorized customers can accessibility data at allowed times. �Most DBMSs enable different level of access privileges come be established for each ar in the database, defining the actions that a details user or group can perform.


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Data defense �Access privileges because that data involve creating who can enter brand-new data, modify existing data, delete undesirable data, and also view data. ◦ Ex. A college student would have actually read-only privileges: enabling them to view the perform of available classes but not readjust them. ◦ Ex. A department head would be able to modify the data. ◦ Ex. Various other users would have no access privileges come the data.


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Data security �Many organizations adopt a principle of least privilege policy, whereby users’ accessibility privileges are minimal to the shortest level vital to perform required tasks.


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Backup and Recovery �Occasionally a database is damaged or destroyed, so a DBMS offers a selection of approaches to gain back the database come a usable form. �A backup, or copy, that the whole database have to be made on a continuous basis. �Some DBMSs have a built-in backup utility if others require a different utility.


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Backup and also Recovery �More complicated DBMSs maintain a log, which is a listing of activities that modify the components of the database. ◦ Ex. A it is registered clerk modifies a student’s address, the change will show up in the log. �The log in contains: ◦ A copy the the record prior to the change called the prior to image ◦ The change being do ◦ and a copy of the document after the change called the after image ◦ The log in may additionally store who made the adjust and when.


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Backup and also Recovery �DBMSs that develop logs usually provide a recovery unit, which uses the logs and/or backups to regain a database as soon as it i do not care damaged or damaged using rollforward and also rollback techniques. �In a rollforward, or front recovery, the DBMS supplies the log to reenter transforms made come the database due to the fact that the last save or backup. �In a rollback, or backward recovery, the DBMS uses the log to undo any kind of changes made to the database throughout a details


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Backup and also Recovery �Continuous back-up is a backup setup in which all data is donate up whenever a change is made. �Continuous backup provides restore in a issue of seconds. �This method can cost an ext but is farming in popularity because of its benefits.


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Relational, Object-Oriented, and also Multidimensional Databases �Every database and DBMS is based on a details data model. �A data model is composed of rules and standards that define how the database organizes data.


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Relational, Object-Oriented, and also Multidimensional Databases �Three famous data models in usage today space relational, object-oriented, and multidimensional. �Some are called object-relational databases due to the fact that they integrate features of the relational and objectoriented data models.


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Relational Databases �A relational database is a database the stores data in tables the consist the rows and columns. �Each row has a primary crucial and every column has a distinct name. �A developer of a relational database refers to a file as a relation, a record as a tuple, and also a field as an attribute.


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Relational Databases �A user the a relational database describes a document as a table, a record as a row, and also a ar as a column. �In enhancement to storing data, a relational database also stores data relationships, which are links within the data. �With a relational database, you can collection up a relationship in between tables with common fields.


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Relational Databases


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Relational Databases �A developer the relational databases supplies normalization come organize the data in the database. �Normalization is a procedure designed to ensure the data in ~ the connections (tables) contains the the very least amount the duplication.


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SQL �Structured query Language (SQL) is a popular query language that permits users come manage, update, and also retrieve data. �SQL has actually special keywords and also rules that users encompass in SQL statements.


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Object-Oriented Databases �An object-oriented database (OODB) shop data in objects. �An object is an object that contains data, and the actions that check out or process the data. �OODBs have the right to store much more types of data than relational databases, accessibility data faster, and permit programmers to reuse objects.


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Object-Oriented Databases �A multimedia database stores images, audio clips, and/or video clip clips. ◦ Ex. Voice mail mechanism �A groupware database stores papers such as schedules, calendars, manuals, memos, and reports. ◦ Ex. Schedule for conference times.


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Object-Oriented Databases �A computer-aided style (CAD) database shop data around engineering, architectural, and scientific designs. ◦ includes a list of components of the item gift designed, the relationship among components, and design drafts. �A hypertext database consists of text web links to other varieties of documents. �A hypermedia database has text, graphics, video, and sound.


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Object questions Language �Object-oriented and also object-relational databases often use a ask language referred to as object query language (OQL) to manipulate and retrieve data. �OQL is similar to SQL and also uses numerous of the exact same rules, grammar, and keywords.


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Multidimensional Databases �A multidimensional database stores data in dimensions. �Whereas a relational database is a two-dimensional table, a multidimensional database can store more than 2 dimensions that data. �These lot of dimensions, known as hypercube, allow users to access and analyze any type of view the the database data.


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Multidimensional Databases �The number of dimensions varies. ◦ Ex. A retail service might have actually 4: products, customers, regions, and also time. �Nearly every multidimensional database has a dimension of time. �Multidimensional databases have the right to consolidate data much faster than a relational database.


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Data Warehouses �One applications that uses multidimensional databases is a data warehouse, i m sorry is a huge database the stores and also manages the data required to analyze historical and current transactions. �A data warehouse frequently has a userfriendly user interface so users have the right to easily interact with the data.


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Data Warehouses �Data in a spread database exists in countless separate places through a network or the Internet and is easily accessible through a solitary server. �Data warehouses regularly use a process called data mining to find patterns and relationships among data. ◦ Ex. E-commerce because that customer choices �A smaller version that a data warehouse, a data mart, has a database the helps a details group or department do decisions.


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Web Databases �Much the the details on the net exists in databases save on computer on the Web. �Some internet databases space collaborative databases, where users store and share photos, videos, recordings, and other an individual media v registered users. �The net page is provided as the front end to the database.


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Web Database �A web database usually lives on a database server, i m sorry is a computer that stores and provides accessibility to a database. �One kind of regimen that manages the sending and receiving of data in between the former end and the database server is a CGI (Common Gateway Interface) script.


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Database administration �Managing a company’s database requires a an excellent deal the coordination. �The function of coordinating the usage of the database belongs to the database experts and administrators.


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Database design Guidelines �A very closely designed database makes it simpler for a user to query the database, change its data, and also create reports. ◦ recognize the purpose of the database ◦ style the tables or files ◦ style the records and fields for each table ◦ determine the relationship amongst the tables




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Role the the Database experts and Administrators �The database analyst (DA), or data modeler, focuses on the definition and consumption of data. �The DA decides ~ above the appropriate placement of fields, defines the relationships amongst data, and also identifies users’ access privileges. �The database administrator (DBA) calls for a much more technical inside watch of the data. �The DBA creates and also maintains the data dictionary, manages defense of the database, monitors the power of the database, and checks backup and recovery procedures.


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Role of the Employee as a User �Today, employees accessibility databases from their office desktop computer computers, notebook computers, or also smart phones and other mobile devices. �Employees interact with databases pertained to inventory and identify brand-new data in the database.