Introduction to Types of Database Models
Database models are basically known as database schemas, which are used to represent database structure and the format of database which is managed by the database management system. The database models represent the look and feel of the database. There are various types of database models like network model, entity-relationship model, hierarchical model, object-oriented model and object model. These all types of database models have different looks from each other and the operations performed on this type of database model are different from each other. The uses of database models vary as per the user requirements.
Types of Database Models
Given below are the different types of database models:
1. Flat Model
In the flat database model, there is a single two-dimensional array of the data elements in which columns are assumed to have a similar type of values and in the row, the elements should have relational value relational to one another.
For example, there are two columns named as name and password which can be used by any security 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 storing the database. This database model has a disadvantage as it is unable to store huge chunks of data in the two-dimensional array because it is difficult to manage such a large set of entries in a flat database model.
2. Hierarchical Model
In the hierarchical model, the data is stored in the tree-like structure in which there is a root node where the data is started to store. The sort field is used for the sibling record to maintain some order while storing data in the hierarchical model. The hierarchical database model is mostly used when there is a need for maintaining an information management system. In this database model there exist a one-to-many relationship among data. The retrieval of data has a different technique in the hierarchical model.
The technique follows navigating a downward direction using the pointers so that data can be accessed sequentially. Because of this technique, the hierarchical database model has a disadvantage as it is not capable of handling all types of database operations. The retrieval time of data is more compare to other types of database models. The records are not connected to the hierarchical model. And the model consists of an upward link that is used to represent the hierarchy of data stored in the database system.
3. Network Model
The network structure database model has a very similar structure as compared to the hierarchical model. This model allows a many-to-many relationship in the tree-like structure model. It means there can be multiple parents. The network model uses the two fundamental concepts i.e. sets and records. The records contain file which can be in hierarchical form and sets which are used to define 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 particular parent can appear more than once in each circle.
In the network database model, the records are connected to each other. In this manner, the hierarchy is maintained among the records. The data access 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 to any particular record. The disadvantage of this network model is that it contains redundancy among the records which means one record can appear more than one time in the database model.
4. Relational Model
The relational database model is designed to remove the dependency in the database management system. The development of the relational database model is targeted for mostly microcomputer systems. The three keys which are used in relational database models are domains, attributes, and relations. The relation is defined as a table that contains rows and columns. The columns present in the table are called attributes in the relational database model. And the domain is defined as a set of values that can be inserted in the database model. The data structure used is a table in this model and the data is stored in the form of rows and columns in the model. The rows are also known as tuples.
For example, there is a relation named employee details. It can have multiple attributes like name, age, gender. And there can be multiple tuples for one single relation named as employee details. The key which can be used to uniquely identify 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.
By this key, the two table location table and employee table can join and the operations can be performed on the join table. The relational database model uses the structured query language (SQL) to perform operations on the database system. The relational model contains multiple tables which look like flat database model. One of the key advantages of this model is whenever the value appears more than on time in two different records there exist some relationships among them.
5. Dimensional Model
The dimensional database model is defined as a specialized version of the relational database model. This model is used to represent data in the data warehouses in such a manner so that data can be summarized using OLAP queries and online analytical processing. In the dimensional database model, the database schema consists of a single table of a huge size which contains facts and dimensions. The dimension is used to define 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.
Conclusion
The database models are widely used to store data in different structural forms. The goal is to maintain the structure properly so that data retrieval time is minimum as possible. And the database operations can be performed easily in different types of database models.
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