chapter 10

                                                                    Chapter 10

-Database is a structured set of data held in a computer, especially one that is accessible in various ways.

-Data is defined as facts or figures, or information that's stored in or used by a computer. An example of data is information collected for a research paper. An example of data is an email.

-Information processing is the change (processing) of information in any manner detectable by an observer.As such, it is a process that describes everything that happens (changes) in the universe, from the falling of a rock (a change in position) to the printing of a text file from a digital computer system.

-A database management system (DBMS) is a computer software application that interacts with the user, other applications, and the database itself to capture and analyze data. Also users to : create a computerized database , add/modify/delete ,sort and retrieved ,create forms and report forms data .

-Data integrity is a fundamental component of information security.

-Garbage in, garbage out (GIGO) in the field of computer science or information and communications technology refers to the fact that computers, since they operate by logical processes, will unquestioningly process unintended, even nonsensical, input data ("garbage in") and produce undesired, often nonsensical, output.

- Valuable information should have the following characteristics : accurate ,verifiable ,timely ,organized , accessible ,useful, cost effective.

-Data hierarchy refers to the systematic organization of data, often in a hierarchical form. Data organization involves fields, records, files and so on. A data field holds a single fact or attribute of an entity. ... A record is a collection of related fields.

- Common data types include : text ,data ,numeric ,memo ,object , auto number, yes/no , attachment ,currency, hyperlink.

-A record type is a data type that describes such values and variables. Most modern computer languages allow the programmer to define new record types.

-A primary key, also called a primary keyword, is a key in a relational database that is unique for each record.

-File maintenance is the periodic updating of master files. For example, adding/deleting employees and customers, making address changes and changing product prices.

-Validation is an automatic computer check to ensure that the data entered is sensible and reasonable. It does not check the accuracy of data.

-File processing system :

•Each department has its own set of files

•Used for many years

•Have data redundancy

•Isolate data.

-Database approach  is a way in which data is stored within a computer. It is organized into various charts that are accessed by a variety of computer applications from different locations.

-Data dictionary is a set of information describing the contents, format, and structure of a database and the relationship between its elements, used to control access to and manipulation of the database.

-Database system provides several tools that allows users and programs too retrieve and maintain data in the database: Query language

                                            Query by example

                                            form

                                            Report generator

-Query language is a language for the specification of procedures for the retrieval (and sometimes also modification) of information from a database.

-Query by example  is a database query language for relational databases.

-Form is a window on the screen that provides areas for entering or modifying data in a database.

-Report generator is a computer program whose purpose is to take data from a source such as a database, XML stream or a spreadsheet, and use it to produce a document in a format which satisfies a particular human readership.

-DTBS provide a variety like : backup ,log ,recovery utility, continuous backup.

-Data model consists of rules and standards that define how the database organizes data.

- A relation database stores data in tables that consist of rows and columns.

-Structured query language is a standard computer language for relational database management and data manipulation. SQL is used to query, insert, update and modify data.

-A multidimensional database (MDB) is a type of database that is optimized for data warehouse and online analytical processing (OLAP) applications.

-data warehouse (DW or DWH), also known as an enterprise data warehouse (EDW), is a system used for reporting and data analysis, and is considered a core component of business intelligence.

-Database on the web allows to: buy/sell, search for a job etc...