Types of Data Models
Explain various Data Models used in DBMS.
There are different types of data models:1. Relational Model
The relational model is developed by E.F. Codd. relational record relatiaonal record-based relational database is a type of record-based relation.
-Relational database is an attempt to simplify the data structure by making use of tables. Tables are used to represent the data and their relationships. A table is a collection of rows and columns. Tables are also known as relations.
-Records are known as tuples and fields are known as attributes.
-The relational model is called;({a record-based model because the database is structured in fixed format records of different types. A record consists of fields or attributes.
-In the relational model, every record must have a unique identification or key based on the data.
In the following table, Stud_ID is the key through which we can identify the record wriquely uniquely in the relatiOT'._-Relational data model is the most widely used record-based data model.
Advantages of Relational Data Model
a)Supports SQL
-For accessing the data in the Relational data model we have a language known as Structured Query Language (SQL).
-This language is used to access, and insert. update or delete the data from the table. By using a relational data model we can execute the complex queries.
b)Flexible
-We can easily manipulate the information which is linked with various tables.
-We can extract the information from different tables simultaneously by using this model.
2. Hierarchical Model
-A data model in which the data is organized into_ a tree structure is known as a hierarchical data model.
Hierarchical data model structure contains parent child relationship where the root of the tree is a par. ent which then branches into its children. It is another type of record-based data model.
-The data is stored in the form of records. These records are connected to one another.
-A record is a collection of fields; each field contains only one value. The hierarchical data models represent ta according to its hierarchy
-In the hierarchical model, there is a business rule. The rule is that one pare!!_t_ node can have many child nodes but one child node can have only one parent node. This type of model is not in use currently.
Advantages of Hierarchical Model
a)Simple to understand: Due to its hierarchical structure, it is easy to understand. Most of the time data have a hierarchical relationships hierarchical relationship. Therefore, it is easy to arrange the data in that manner.
b)Database Integrity: In a hierarchical data model there is always a pare. it child association between different records on different levels. Due to this inherent structure integrity gets maintained.
c)Efficient: The performance of this model is very efficient due to its hierarchical structure when a database contains a large amount of data that has various related records.
3. Network Database Model
-It is an extended type of hierarchical data model. This data model is also represented as hierarchical, but any child in the tree can have multiple parents.
-In the network data model there is no need for the parent-child association. There is no downward tree structure.
-It is a flexible way of representing objects and their relationship. A network data model allows multiple records linked in the same file. '
-Basically, the network database model forms a network-like structure between the entities.
Advantages of Network Model
a)Design is simple: The. network rrwdet is simple and easy to design and under d. There is no complex structure in the network model.
b)It can handle various relationships
4 Entity Relationship (E-R) Model:
- This model describes interrelated things of interest in a specific domain of knowledge. An ER model is composed of entity .types (which classify the things of interest) and specifies relationships that can exist between instances of those entity types. In the next Sections 1.10 and I. ll, we will study this model in detail.
Advantages of Entity Relationship Model:
a) Simple Design: The ER model is simple and easy to design. It shows the logical view of the data and its relationships. This model is easy to understand.
b) Effective representation: The presentation of the to Entity-Relationship Model is very simple and effective. The programmer and designer can easily understand the flow of the system by referring to the ER Model
c) Connected with Relational Model: The Entity-Relationship Model.is connected with the relational model. Due to this advantage, we can develop a well-structured design.
5 Object-Oriented Database Model
- Object-oriented data model is nothing but the collection of objects or elements with its methods.
- Nowadays all advanced programming languages support the con pts of Object Oriented Programming.
-The network model can handle the one-to-many and many-to-many relationships which is useful to
- This model is a paradigm. This database. based on the paradigm the Object-oriented is defined for
developing the database.
c) Easy to access: The data access is easy and
- It is an extension of the E-R model w with,w with the integration of concepts like object, method, and encapsulation.
flexible than the hierarchical data model. In - the network model there is no hierarchy in the
Applications of data modeling contain the key concepts of object-oriented.
objects and their relations therefore it is very easy
to access the data in the network model.
Advantages of Object-Oriented Data Model:
a) Object-oriented data Model supports inheritance. Due to this, we can reuse attributes and functionalities. It reduces the cost of maintaining data multiple times.
b) Due to inheritance, and encapsulation this model becomes more flexible.
c) We can bind each class with its attributes and functionality. It helps in representing real-world objects.
d) We can see each object as a real-world entity in this model. Hence it is more understandable.
6 Physical Data Model:
- The description of data storage in the computer in the form of information is provided by Physical data models.
The physical data model shows the table structure which includes column name, column data, constraints, and foreign relationship the between · tables. Physical data models define all the components of
logical database.
Advantages of Physical Model
a) We can specify the all tables and columns using the physical data model.
b) We can use a foreign key to join the tables. By using foreign keys we can identify the related data from the different tables.
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