Database models are primarily known as database schemas, which are used to express database structure and the format of a database that is maintained by the database management system DBMS. The database models describe the attention and feel of the database. There are different types of database models like a hierarchical model, Flat Model, Network Model, and Context model. These all kinds of database models have separate looks from each other and the actions implemented on this type of database model are distinct from each other. The uses of database models modify as per the user demands.
Types of Database Models
Given below are the different types of database models:
- Hierarchical Model
- Flat Model
- Network Model
- Dimensional Model
- Relational Model
- Context model
Hierarchical Model
In the hierarchical model, the data is saved in the tree-like structure in which there is a root node where the data is originated to save. The sort field is used for the sibling record to have some order while saving data in the hierarchical model. The hierarchical database model is often used when there is a need for managing an information control system. In this database model there exist a one-to-many relationship among data. The retrieval of data has many techniques in the hierarchical model.
The technique follows operating a descending direction using the pointers so that data can be accessed sequentially. Because of this system, the hierarchical database model has a limitation as it is not capable of handling all types of database operations. The retrieval time of data is more parallel to other types of database models. The records are not compared to the hierarchical model. And the model consists of a higher link that is used to describe the hierarchy of data saved in the database system.
Flat Model
In the flat database model, there is a single two-dimensional array of the data elements in which columns are supposed to have a comparable standard of values and in the row, the elements should have relational value and relational to one another.
For example, there are two columns called username and password which can be used by any safety system. So each row is used to store different passwords and usernames. No two entry is the same in the flat model. In the flat model, the table format is used for saving the database. This database model has a limitation as it is unable to store huge chunks of data in the two-dimensional array because it is hard to maintain such a large set of entries in a flat database model.
Network Model
The network structure database model has a similar structure as connected with the hierarchical model. This model provides a many-to-many relationship in the tree-like structure model. It means there can be multiple parents. The network model uses the two basic concepts i.e. sets and records. The records hold file which can be in hierarchical form and sets which are used to represent the many-to-many relationship among the records. The set uses the circular linked list as the data structure in which one record which is a parent can appear once in a circle and the child of that special parent can appear more than once in each circle.
In the network database model, the records are correlated to each other. In this way, the hierarchy is preserved among the records. The data path in this database model is either in sequential form or can be in a circular linked list pattern. And there can be multiple paths to access any special record. The problem of this network model is that it holds redundancy among the records which indicates one record can perform more than one time in the database model.
Dimensional Model
The dimensional database model is represented as a specific version of the relational database model. This model is used to describe data in the data warehouses in such a way so that data can be compiled using OLAP queries and online analytical processing. In the dimensional database model, the database schema consists of a single table of a large size that contains facts and dimensions. The dimension is used to describe the context of fact and is in hierarchical form. The dimensional database model uses the star schema which contains a highly normalized table that has facts and dimensions.
Relational Model
The relational database model is composed to remove the dependency in the database management system. The development of the relational database model is targeted mostly at microcomputer systems. The three keys which are used in relational database models are domains, relations, and attributes. The relation is represented as a table that holds rows and columns. The columns present in the table are called attributes in the relational database model. And the domain is described as a set of values that can be inserted into the database model. The data structure used is a table in this model and the data is saved in the form of rows and columns in the model. The rows are also known as tuples.
For example, there is a relation named man/woman details. It can have multiple attributes like name, age, gender. And there can be multiple tuples for one single relation named man/woman details. The key which can be used to uniquely recognize any row is called the primary key. And these keys can be used to join more than one table at the same time. For example, there can be a column named location in the employee table and the column location can be the primary key of the location table.
Context model
This model can incorporate elements from other database models as required. It cobbles together elements from object-oriented, semistructured, and Network models.
Conclusion
The database models are extensively used to save data in different structural forms. The goal is to preserve the structure well so that data retrieval time is minimal as feasible. And the database operations can be implemented quickly in different types of database models.