ABSTRACT DATA The main purpose of database system is that user can arrange a view of data abstraction. It aims to simplify the intraction between users with the system and the database can present different views to its users, programmers, and administrators. Since not all database users are well trained and users are divided into various levels, the database complexity will be hidden from the user through multiple levels of data abstraction. When looking at the database, users can be grouped into 3 levels (levels), namely:
>Physical Level (physical view / internal view). It is the lowest level in data abstraction showing how data is stored in actual conditions. This level is the most complex form, where the lowest level data structure is depicted at this level.
>Conceptual Level. It is a level that describes what data is actually (functionally) stored in the database, along with the relationships that occur between the data. This level describes the entire database, where the database administrator (DBA) builds and processes the database, while the user does not care about complexity in the physical level structure again. For example: the user will know that the sale is stored in the table of goods, production, finance, marketing.
>User View Level. It is a level with the highest level, which describes only one part of the entire database. Some database users do not need all the contents of the database eg the personnel section only requires employee file data and salary, does not require the data file warehouse, transaction goods entered.
The data abstraction level can provide an overview or view of the architecture of the Database Management System (DBMS), which will add to the notion of data independence. Data independence can be divided into two parts:
>Physical Data Independence
Ability to change the physical pattern of a database without causing a program application to be rewritten. Modifications to the physical level are usually at the time of improving usability.
>Logical Data Independenceata model Data model is a collection of concepts that can digunakakn to draw the data structure. Database structure includes data types, relationships, and some requirements that must be met database.
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In one file there are records of the same kind, the same size, the same form, which is a set of uniform entities. A record consisting of an interconnected field indicates that the field is in one complete sense and recorded in a single record. Each field value or content has the same space or width capacity. The type of data content of a field must match its data type. The name of a file should describe the contents of the data file. To complete the definition of a file, in the database known entity names (entities) and attributes. Entetis is the person, place, event, or concept whose information is recorded. each entity has an attribute or a title to represent an entity. For example in a lecture system; mahasiwa, course, payment, lecturer is as entity. Whereas student entity has attribute of parent number, name, department, and so on. Or from the above example the entity is an employee, ang has NIP attribute, name, address, tgl_lahir, jns_kel The database system is a combination of database and database management system (SMBD). A complex database and accompanied by documentation techniques and manipulation procedures will establish a Database Management System (DBMS). In short the DBMS is a database and a program to access it.

The above definition can illustrate to us that the database has several important criteria, namely:

>Data-oriented and not program-oriented.
>Can be used by some application programs without needing to change its data base.
>Can be developed easily, both volume and structure.
>Can meet the needs of new systems easily.
>Can be used in different ways.

The components of the database system are:

>Hardware, as a support for data processing operations such as CPU, memory, disk, terminal, and so forth.
>Software operating system, (Windows 9x, Windows 2000 / XP, Linux, Unix.)
>Database management software (DBMS) such as MS-Access, SQL, Oracle.
>Software application programs such as Visual Basic, Delphi, Visual Foxpro.
>Database (all data required, maintained, managed by Database system)
>User / user database (user).

User (user) database includes:

>Database Administrator, a user who has authority as a central controller of all systems both database and programs that access it, determine the pattern of database structure, modify, divide processing tasks and provide a certain orientation, and so on.
>Aplication Programmers, an application programmer that interacts with the system through a Data Manipulation Language (DML) invocation entered into a write program.
Sophisticated Users, ie users who berintraksi with tapa system must write their own program, but replaced with a request (request) in the form of database query language. Such as using MS-Accsess, SQL, and so on.
>Specialized Users, users who write special database application programs that do not fit the traditional data processing framework. Examples: expert system, multimedia, and so forth.
>Naive Users, ie most users who mengintraksi with the system by calling one of the application programs that have been provided. Example: the operator on the teller, personnel, and so forth.

THE ROLE OF DATA BASES The data base is important in the management of data in using the computer, because bebrapa reasons are:

>As a major component or important in information systems, as it is the basis for providing information.
>Determine the quality of information fast, accurate, relevant, so that the information presented is not stale.     Information can be said to be worth when the benefits are more effective than the cost of getting it.

Preparation of a database is used to overcome the problems on the preparation of data. Benefits derived from the preparation of the database are to:

>Addressing data redundancy. The same data storage in some places besides can make it difficult for the user about data actualization also wasting the storage place, then the database will detect and avoid in case of data kerangkapan.
>Avoiding data inconsistencies. Another consequence if there is data kerangkapan, then if there is a change in the data one while the other is not changed will occur data inconsistency. For that the database will adjust to the same data in case of changes, if all data will always be updated
>Overcoming difficulties in accessing data. Facilitate if one day will be taken or printed data that has certain criteria, for example on a certain date, a particular address, a certain amount, and so forth.
>Formulate the standard format of a data. Dta ayang same on different files must have the data format of the type and the range should be the same. The inequality of the data format will result in difficult or inefficient access to other data.
>Usage by multiple users. A database can be utilized simultaneously by multiple users (multiuser)
Conducting protection and data security (data security). Any data can only be accessed over manipulated by the authorized party by providing login and password to each data.
>Develop data integrity and independence. The database is complex data that can be integrated, so we can manipulate to get various forms of worksheets and reports we want. However, each data is not interdependent on other data. The data in the database can stand on their own.

Database or database
Database or database is a collection of information stored in the computer systematically so that it can be accessed using a computer program to obtain information from the database. The software used for query management and query databases is called database management system (database management system, DBMS). Data-driven system.

The term "basic data" starts with computer science. However it is getting wider, enter things outside the field of electronics, this article on computer databases. Similar records to the database actually existed before the industrial revolution in the form of ledgers, receipts and data related to business.

The basic concept of a database is a collection of records, or pieces of knowledge. A database has a structured explanation of the types of facts stored in it: this is called schemas. The schema describes the object represented by a database, and the relationship between the object. There are many ways to organize the schema, or model the database structure: this is known as a database model or data model. The commonly used model now is the relational model, which, in layman terms, represents all information in the form of interconnected tables in which each table consists of rows and columns (the actual definition uses mathematical terminology). In this model, relationships between tables are represented by using the same values ​​between tables. Other models such as hierarchical models and network models use a more explicit way to represent relationships between tables

The term database refers to a collection of interconnected data, and the software should refer to a database management system (DBMS). If the context is clear, many administrators and programmers use database terms for both meanings.

So the concept of a database or database is a collection of data that form a file (file) are interconnected (relation) with certain procedures to form new data or information. Or database (database) is a collection of interconnected data (relation) between one another that is organized based on a particular scheme or structure. On a computer, the database is stored in a hardware storage device, and with certain software is manipulated by certain interests or interests. Relationships or data relationships are usually indicated by the key (key) of each file. Data is a fact or value (value) that recorded or represent the description of an object. Data that is a recorded fact and subsequent processing (process) into a useful form or useful for the wearer will form what is called information. The complex and integrated form of information and processing of a database with the computer will be used for the decision-making process in management to develop the Management Information System (MIS), the data in the database is the smallest and most important item to build a good and valid database. Data in the database is integrated and shared:

      Integrated (integrated), the data files in the database are interrelated (data dependencies occur);
      Shared data (shared), the same data can be used by a number of users at the same time. Often called            multiuser system

Data is a very useful resource for almost all organizations. With the availability of abundant data, then the problem of regulating data effectively becomes a very important thing in the development of management information system. Therefore, the purpose of the arrangement of data is as follows:

     Provides data storage to be used by organizations now and in the future.
     As a means of data entry so as to facilitate the task of the operator and also related to the time required         by the user to obtain the data and rights owned to the data handled
     Control of data for each cycle to keep data up to date and can reflect the specific changes that occur in         each system.
     Security of data against possible additions, modifications, theft, and other disturbances.

A database building has the following levels:

     Characters, are the smallest pieces of data in the form of numbers, letters, or special characters that                makeup a data item or field. Examples A, B, X, Y, 2,1,2,9,0, =, <,> and so on.
     Field / item, is a representation of an attribute and record (tape / tuple) of a kind that shows an item of           data. Name field example (contains data of employee names), department field (contains part data or job       specification), and so on.
     Record / tape / tuple: A collection of fields form a record or recording. Records describe a specific unit         of individual data. Example: employee file, where each record contains a collection of data names,                 addresses, departments, which can represent each data.
     File, is a collection of records that describe a unity of similar data. Examples of employee files contain           data about all employee-related personnel such as employee name, employee's address, department,             which can represent each data.
     Database, is kumupan of file or table that form a database. An example of PT Maju Continent employee       database consists of employee files, payroll files, group files, and so on.