Difference between Hierarchical Database and Relational Database

The storing and processing of data in database management systems is one of the most significant functions that business organisations perform with their data. Users of a database management system can access their data in the way they like, because the system hides the storage details. Users are provided an abstraction of the data through the usage of database models.

When it comes to building databases, the two most popular types of database models are hierarchical and relational.

What is a Hierarchical Database?

IBM's first attempt at developing a data model in traditional database systems, which took place in 1968, resulted in the hierarchical data model. It is a model in which the data is stored in a parent-child model, but the child in question has only one parent.

  • It creates a structure similar to a tree, where the records act as child nodes and are connected to one another by links. The initial node in the tree structure is referred as the root node.

  • A single child node can only have one connection to its parent node, even though the parent node can have several child nodes. As a result, both one-to-one and one-to-many relationships are supported by the hierarchical database model.

  • The simplicity and consistency with which one can access one's data is perhaps the most significant benefit offered by a hierarchical database.

  • Both the "fetch" and the "update" operations are straightforward to optimise. The hierarchical database structure is straightforward yet adaptable.

Drawbacks of Using Hierarchical Database

Here is a list of some of the drawbacks of using a hierarchical database −

  • The fact that the database's linkages are hardcoded and cannot be changed is the system's most significant shortcoming.

  • If there is any chance that the database may need to be modified in the future, then the entire database will have to be reconstructed.

  • It saves redundant information, which makes it more difficult to retrieve the material later on.

  • Because the hierarchical database has to be coded into the application, any change that is made to the database necessitates the developer making changes to the code that is in the application.

Hierarchical databases are still utilised on IBM mainframes, despite the fact that their use is discouraged in today's application development.

What is a Relational Database?

E.F. Codd is credited with developing the relational database model in the year 1970. The records in a relational database are saved in the corresponding tables. The tables are organised in rows and columns, with each row representing a different entity and each column describing an attribute of a record. Tables and relations are only connected when they have characteristics in common with one another.

  • Relational databases are more popular in industries than hierarchical databases because they are easier to use, more straightforward to program, and need less maintenance.

  • Oracle, DB2, Microsoft SQL Server, and Informix are examples of relational database management systems. Other options include MySQL.

  • A relational database is not dependent on the applications that use it, and any changes made to the database will not have any effect on the application programming.

  • Relational databases may also be used for simply constructing complex associations between tables, which is a useful capability.

  • In relational database systems, the logical structure of the data is stored in a distinct location from where the data itself is physically stored. This allows for the structures to be managed in a manner that is distinct from one another without influencing one another.

  • Integrity rules are followed in relational databases in order to prevent the entry of duplicate data into the tables. In order to access the data from the database in a manner that is both reliable and precise, the SQL query language is utilised.

Relational databases keep data in a consistent format, which makes it easy to retrieve any necessary databases. During times of crisis, it is not only simple to create backups of the data but also simple to import and export it.

Difference between Hierarchical Database and Relational Database

The following table highlights the differences between a Hierarchical database and a Relational database −

Basis of comparison
Hierarchical Database
Relational Database
Developed byIBM in 1968E.F. Codd in 1970
ComplexityMore complexity is possible.No possibility of complexity.
IndependenceData independence is lacking in this paradigm.Data independence is provided by this model.
GenerationIt is a data model of the very first generation.It is a data model of the second generation.
StructureA hierarchical structure in the form of a tree, with parent nodes and child nodesTabular representation, which consists of rows and columns
RelationshipsOne-to-one, one-to-manyOne-to-one, one-to-many, many-to-many
Data retrievalThe tree must be traversed from root to required node.SQL query language is used.


In a nutshell, the two primary kinds of databases are relational databases and hierarchical databases. The most important distinction between a hierarchical database and a relational database is that the former adheres to the relational model and organises its data in tables, while the latter adheres to the hierarchical model and organises its data in a tree-like structure.

Updated on: 28-Jul-2022

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