Uderstanding Database

UNDERSTANDING DATABASE

 

The database is a collection of related data, organized in such a way, stored in a particular storage medium without the monetization (redundancy), so that later can be recovered quickly and easily. In another sense the data base (in English: a database), or databases are often spelled, is a collection of information stored on the computer in a systematic way so that it can be checked using a computer program to obtain information from the database. The software used to manage and call the query (query) data base called a database management system (database management system, DBMS). Database systems are studied in information science.

The term "database" originated from computer science. Despite the increasingly widespread then it means, put things outside the field of electronics, this article is about computer databases. Note that similar to the data base is already there before the industrial revolution in the form of ledgers, receipts and collection of data related to the business.

The basic concept of the database is a collection of records, or pieces of knowledge. A structured database has an explanation of the types of facts that are stored in it: the explanation is called a schema. The scheme describes the objects that represented a data base, and the relationship between these objects. There are many ways to organize the scheme, or modeling the database structure: this is known as the model database or data model. Model commonly used today is the relational model, which is layman's terms represents all information in the form of tables that are interconnected with each table consists of rows and columns (the true definition uses mathematical terminology). In this model, relationships between tables are represented premises 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 the collection of data related to each other, and the software should be referred to as a database management system (database management system / DBMS). If the context is clear, many administrators and programmers use the term data base for both these meanings.

Database software 
Database software are widely used in programming and database tools are high level (high level): Microsoft SQL Server, Oracle, Sybase, Interbase, Xbase, Firebird, MySQL, PostgreSQL, Microsoft Access, dBase III, Paradox, FoxPro, Visual FoxPro, Arago, Force, Recital, dbFast, dbXL, Quicksilver, Clipper, Flagship, Harbour, Visual dBase, Lotus Smart Suite and Approach.

In addition to the above software, there are also database programming software low level (low level), including:Btrieve and Tsunami Record Manager

Data base System Advantages: 
1. Speed ​​and easy (Speed)
2. Storage Space Efficiency (Space)
3. Accuracy (Accuracy)
4. Availability (Availability)
5. Completeness (Completeness)
6. Security (Security)
7. Togetherness (Sharability)
 
Terms in the Database.

1. Table. 
The table is part of a database that stores data grouped in the form of rows and columns like a spreadsheet. Each row represents a record, and each column is an attribute or field. Each column contains one type of information.

2. View. 
View can be defined as a virtual table (virtual) or a logical that consists of a set of query results. Unlike most tables in a relational database, the view is not part of the physical schema. View is dynamic. It contains data from the table that it represents. Thus, when the table is the source data changes, the data in view will also change.

3. Entities. 
Entities are a group of the object, (in the world of OOP is called a class) that have attributes.

4. Attribute (field). 
Attributes are qualitative traits possessed by an object, which reflects the properties of the object. Field data of the smallest states have meaning. Another term for the field of data elements, the column item. Examples of fields that a person's name, the number of items purchased, and the person's date of birth.

5. Record (recording) 

state data collection from a number of interrelated elements. For example, name, address, date of birth, and gender of the person preparing a record. Another term that also claimed the record of tuples and rows.

6. Key attributes. 
Key attribute is an attribute that is unique, meaning no other objects are still one entity has the same attribute values.

7. Relation. 
Relation is a relation between the tables that represent relationships between objects in the real world. Various Kinds Relationships between tables:

a. One-to-many. 
Suppose there is a relation between mother and child table table relation name "has" and the relationship one-to-many. That is one record in the table may relate to the mother (had) a lot of records in child table. But one record in the child table may only relate to one record at a table alone mothers Pictures relation one-to-many.

 b. One-to-one.
If two tables to relate one-to-one means that each record in the first entity will only be associated with one record at a second entity and vice versa. Conrohnya relation between the tables employees and employee address. One employee records relate only to one record beitu employee addresses and vice versa. Entity 3 is a unique attribute in the entity 4. Figure relationship one-to-one.

 c. Many-to-many. 
If the table relates to one of two tables with any relation-to-many means that there are many records in entities and entities of the two that are interconnected with one another. For example the relation many-to-many transactions between the tables and stuff. The transaction record can be associated with many records of goods, and vice versa. Figure relation many-to-many: In the database, required an analytical technique of determining the entities, attributes and relationships among entities. Usual determination is based on a Memorandum of clients (companies) are asking to be made database. Here's an example analysis of the data list items, entities, attributes, and relationships between entities that exist.

DATABASE CONCEPTS
 
According Edhy Sutanta (2004:1-3), knowledge of database concepts emerge and begin to grow in line with the needs of data processing to meet the information needs. The development of the concept of a data base can be divided into five stages, namely:

1. Phase I (early 1960s), development of computer technology that had been discovered in 1945, has spawned new views and knowledge about the concept of storing data in a database, which uses many previous manual methods. The concepts of data base developed at that time known as the concept of phase I. The data base Feature of the database concept of Phase I is the data processed on the basis of the file (file processing) on ​​a mainframe computer environment.

2. Phase II (late 1960s), in the late 1960's saw a striking advances and changes in the concept of a data base and further the concepts of data base at that time referred to as the concept of phase II data base. At this stage has been changing and improving the methods of storage in the database. The main characteristic of this stage the data base concept is the concept of database system (Data Base Systems / DBS), the concept of database management system (Data Base Management Systems / DBMS), information services online and text-based information services.

3. Phase III (early 1970s), the development of methods of data storage in a better data base occurred in the early 1970's. Storage hardware that is used when it has been getting better. These conditions have affected their views and knowledge of database concepts is the better. Furthermore, the concepts of database as it is referred to as the concept of phase III data base. The main feature of the database concept in phase III is the emergence of database applications based expert system (Expert Systems / ES) in decision support systems (Decission Support System / DSS), as well as object-oriented programming (Object Ocriented Programming / OOP).

4. Stage IV (beginning in the 1980s), very rapid development in computer technology and data storage since the 1980's has influenced the views and knowledge in database concepts. This resulted in the emergence of the view changes and new knowledge about the concept of a data base. The concept of a data base at that time known as the concept of phase IV data base. The main feature of the database concept in phase IV is a hypertext-based system that allows the appearance of information based on search queries that can be done at random.

5. Phase V (starting in the 1990s), development of database concept in the 1990's has evolved towards database applications for artificial intelligence systems (Artificial Intelligent / AI), the database for multimedia applications that involve text data , sound, images and animation, object-oriented database application (Object Oriented Data Base / OODB), as well as database applications online (online data base) for a global computer network or the Internet. Application of the concept of fuzzy data base (fuzzy) is also color the concept of database at this time.