What is data modeling for a Database ? DBMS

 DATA MODELING FOR A DATABASE :-

                        Data modeling is a way to structure and organize data so it can be used easily by dases. Unstructured data can be found in word processing documents, email messages, processing by a database. So in a way, data modeling is concerned with how the data looks .

                          Data modeling is routinely used in conjunct with a database management system, Dat INTRODUCTION it has been modeled and made ready for this svstem can be identified in various ways, sle as ccording to what they represent or how thev relate to other data. "The idea is to make da P Dle as possible, so analysis and integration can be done wIth as nnue ettort a necessary.

1. Conceptual Data Modeling - It identifies the highest-level relationships between different entities .
   
   
2. Enterprise Data Modeling - Enterprise data modeling is similar to conceptual dat modeling. but addresses the unique requirements of a specific business. 
   
   
3. Logical Data Modeling This data modeling illustrates the specific entities, attribute and relationships involved in a business function. It serves as the basis for the creation of th physical data model. 
   
   
4. Physical Data Modeling- It represents an application and database-speciti implementation of a logical data model.
   
   
   
   

• DATA INTEGRATION:-

                                               Data integration combines data from multiple sources into a single data store, such as motho data warehouse. These sources may include multiple databases, data cubes, or flat files.

Why Data Integration is required?

                  Often large companies and enterprises maintain separate departmental databases to store the data pertaining to the specific department. Although such separations of the data provide them beter manageability and security, performing any cross departmental analysis on these .

                   For exanmple, if marketing department and sales department maintain two secluded databases, then it might not be possible to analyze the effect of a certain advertising campaign hy the marketing department on sales of a product. Similarly, if HR department and production department maintain their individual databases, it might not be possible to analyze he correlation between yearly incentives and employec's productivity .

                    Data integration provides a mechanism to integrate these data from different departments into a single database schema.

• DATA ABSTRACTION :-
                                              The major purpose of a database system is to provide users with an abstract view of the system. The system hides certain complex details from the user like- how data is stored and shows only those database records to the user which he/she demands. This is called Data sal dat abstraction. 

                                     

           In DBMS, the database can have different aspects to reveal if seen from different levels of abstraction. The term abstraction means the amount of detail you want to hide. Any entity can be seen from different perspectives and levels of complexity to make it a reveal its tribute of the pecific current amount of abstraction. Let us illustrate by a simple example: 

                                                  A computer reveals the minimum of its internal details, when seen from outside. We do not know what parts it is built with. This is the highest level of abstraction, meaning very few details are visible. If we open the computer case and look inside at the hard disk, motherboard, CD drive, CPU and RAM, we are in middle level of abstraction. If we move on to open the hard disc and examine its tracks, sectors and read-write heads, we are at the lowest level of abstraction, where no details are invisible. 

                                        In the same manner, the database can also be viewed from different levels of abstraction to reveal different levels of details. From a bottom-up manner, we may find that there are three levels of abstraction or views in the database:

1. External or User view: In this database view, maximum detail about the database wille hidden from the user. In this view, only the restricted portion of the database is available to end users. It implements highest level of data abstraction .
   
   
2. Conceptual or Logical view: This view will provide some more detail about the database to the user like- structure or schema detail of the database. It implements middle level of data abstraction. 
   
   
3. Internal view: This view will provide internal or storage detail about the database. It implements lowest level of data abstraction .