Please Wait...

download

download
The database is a collection of information stored in computer storage media such as hard disk so that systematically can be checked using a computer program to obtain information on the contents of the database. The software used to manage and call query a database called database management system (database management system, DBMS).
The basic concept of a database is a collection of records, or pieces of knowledge. A database has structured explanation of the type of data that is a collection of facts stored in it (may be referred to as a scheme). Schemes describe the object represented a data base, and the relationship between the objects to other objects such. The means used to obtain such a scheme is one that paluing common approach is to use the model of relational, in which way it works is to look at the relationships between entities (representing a real individual) on the business processes that occur.
ERD (entity relational diagram) is an approach that uses a database of relationships between entities that are described in the data model in the form of graphic notation in the conceptual data model that describes the relationship between the depositor. The data model itself is a collection of methods, tools to describe the data that have relationships with one another, semantic, and consistency constraints. The data model consists of the entity relationship model and relational model. Entity relationship diagrams found in the book by Peter Chen Entity Relational Model-Toward a Unified of Data. Chen the formulation of the fundamentals of the model and after it was developed and modified by Chen and many other experts. At that time the entity relationship diagrams created as part of the software is also a special modification, since no single form and standard of the entity relationship diagram.
download
download 
ERD (entity relational diagram) had a symbol - a symbol in order to make the modeling that where ERD has four symbols: Rectangles, declared entity set. Oval, stating attribute (key attribute is underlined). Rhombus, stated set of relations. Line, stated a link between a set of relations with the entity and the entity set with attribute
ERD in function is used to construct the conceptual data model, modeling data structures and relationships between data and implement database logically and physically with DBMS (Database Management System). With this entity relationship diagram we can test the model by ignoring the process that must be done. Entity relationship diagrams can assist in answering the question of the necessary data and how that data is interconnected .
example for ERD

The database basically have their own language so that in order to create a database we have to understand the language used in the database, where the database language pliers grouped into two, namely:
  1. Data Definition Language (DDL)
  2. Data Manipulation Language (DML)
in addition to having its own language data base also has a stage - in its design stages, namely:
  1. Planning database
  2. Defining the system
  3. Analysis and gather requirements
  4. Database design
  5. application design
  6. Creating a prototype
  7. Implementation
  8. conversion of data
  9. examination
  10. operational maintenance
After understanding the notion and stages and the language used database, we must also know the database software, such as the following: 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 Approach, db2, MongoDB