Question

3.
What are the different types of databases? Explain each of them briefly.​

Answer 1

A system that contains databases is called a database management system, or DBM. We discussed four main types of databases: text databases, desktop database programs, relational database management systems (RDMS), and NoSQL and object-oriented databases.

Answer 2

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☞Types of Database Management Systems:-

☞There are several types of database management systems:-

➝Here is a list of seven common database management systems:-

•Hierarchical databases

•Network databases

•Relational databases

➜Hierarchical Databases:

In a hierarchical database management system (hierarchical DBMSs) model, data is stored in a parent-children relationship node. In a hierarchical database, besides actual data, records also contain information about their groups of parent/child relationships.

In a hierarchical database model, data is organized into a tree-like structure. The data is stored in the form of a collection of fields where each field contains only one value. The records are linked to each other via links into a parent-children relationship. In a hierarchical database model, each child record has only one parent. A parent can have multiple children.

To retrieve a field’s data, we need to traverse through each tree until the record is found.

The hierarchical database system structure was developed by IBM in the early 1960s. While the hierarchical structure is simple, it is inflexible due to the parent-child one-to-many relationship. Hierarchical databases are widely used to build high-performance and availability applications usually in the banking and telecommunications industries.

The IBM Information Management System (IMS) and Windows Registry are two popular examples of hierarchical databases.

→Advantage :

A hierarchical database can be accessed and updated rapidly. As shown in the figure above, its model structure is like a tree and the relationships between records are defined in advance. This feature is a double-edged sword.

→Disadvantage:

This type of database structure is that each child in the tree may have only one parent. Relationships or linkages between children are not permitted, even if they make sense from a logical standpoint. Hierarchical databases are like this in their design. Adding a new field or record requires that the entire database be redefined.

➜Network Databases:

Network database management systems (Network DBMSs) use a network structure to create a relationship between entities. Network databases are mainly used on large digital computers. Network databases are hierarchical databases, but unlike hierarchical databases where one node can have a single parent only, a network node can have a relationship with multiple entities. A network database looks more like a cobweb or interconnected network of records.

In network databases, children are called members and parents are called occupiers. The difference between each child or member is that it can have more than one parent.

The approval of the network data model is similar to a hierarchical data model. Data in a network database is organized in many-to-many relationships.

The network database structure was invented by Charles Bachman. Some of the popular network databases are the Integrated Data Store (IDS), IDMS (Integrated Database Management System), Raima Database Manager, TurboIMAGE, and Univac DMS-1100.

➜Relational Databases:

In a relational database management system (RDBMS), the relationship between data is relational and data is stored in tabular form of columns and rows. Each column of a table represents an attribute and each row in a table represents a record. Each field in a table represents a data value.

Structured Query Language (SQL) is the language used to query RDBMS, including inserting, updating, deleting, and searching records. Relational databases work on each table that has a key field that uniquely indicates each row. These key fields can be used to connect one table of data to another.

Relational databases are the most popular and widely used databases. Some of the popular DDBMS are Oracle, SQL Server, MySQL, SQLite, and IBM DB2.

→The relational database has two major advantages:

1.Relational databases can be used with little or no training.

2.Database entries can be modified without specifying the entire body.

→Properties of Relational Tables

In a relational database, we have to follow the properties given below:

• Values are Atomic
• Each Row is alone.
• Column Values are the same thing.
• Columns are undistinguished.
• Sequence of Rows is Insignificant.
• Each Column has a common name.