Data Model is a logical map that represents the inherent properties of the data independent of software, hardware, or machine performance considerations. The model shows data elements grouped into records, as well as the association around those records.
Since the data model is the basis for data implementation regardless of software or hardware platforms, the data model should present descriptions about a data in an abstract manner which does not mention detailed information specific to any hardware or software such as bits manipulation or index addition.
There are two generally accepted meanings on the term data model. The first is that the data model could be some sort of theory about the formal description of the data’s structure and use without any mention of heavy technical terms related to information technology. The second is that a data model instance is the application of the data model theory in order to create to meet requirements of some applications such as those used in a business enterprise.
The structural part of a data model theory refers to the collection of data structures which make up a data when it is being created. These data structures represent entities and objects in the database model. For instance the data model may that be of a business enterprise involved in sales of toys.
The real life things of interest would include customers, company staff and of course the toy items. Since the database which will keep the records of these things of interest cannot understand the real meaning of customers, company staff and toy item, there should be created a data representation of this real life things.
The integrity part of a data model refers to the collection of rules which governs the constraints on the data structures so that structural integrity could be achieved. In the integrity aspect of a data model, the formal definition of an extensive sets of rules and consistent application of data is defined so that the data can be used for its intended purpose.
Techniques are defined on hot to maintain data in the data resource and to ensure that the data consistently contains value which is loyal to its source while at the same time accurate in its destination. This is to ensure that data will always have data value integrity, data structure integrity, data retention integrity, and data derivation integrity.
The manipulation part of a data model refers to the collection of operators which be applied to the data structures. These operations include query and update of data within the database. This is important because not all data can be allowed for altering or deletion. The data manipulation part works hand in hand with the integrity part so that the data model can result in high quality in the database for the data consumers to enjoy.
As an example, let us take the relational model. The data model defined in the structural part refers to the modified concept of the mathematical relation. The reasoning about such data is represented as n-ary which is a subset of the Cartesian product of n domains.
The integrity part refers to the expression in the first order logic and the manipulation part refers to the relational algebra as well as tuple and domain calculus.
The process of defining a data model is extremely important in any database implementation in that there can only be one data model which is the basis for a wide variety of data implementation.
Hence, any database management system such as Access, Oracle or MySQL can be implementing and maintaining a database based on one data model only.