Database : Database is an organized collection of interrelated data stored in a computer. Show
Importance of Database: • It allows large amount of data to be stored systematically and these data to be easily retrieved, filtered, sorted and updated efficiently and accurately. Types of Database Model Database Model: It determines the logical structure of a database and fundamentally determines in which manner data can be stored, organized and manipulated. There are four common types of database model that are useful for different types of data or information. Depending upon your specific needs, one of these models can be used. 1. Hierarchical databases. 1. Hierarchical databases It is one of the oldest database model developed by IBM for information Management System. In a hierarchical database model, the data is organized into a tree-like structure. In simple language we can say that it is a set of organized data in tree structure. This type of Database model is rarely used nowadays. Its structure is like a tree with nodes representing records and branches representing fields. The windows registry used in Windows XP is an example of a hierarchical database. Configuration settings are stored as tree structures with nodes. The following figure shows the generalized the structure of Hierarchical database model in which data is stored in the form of tree like structure (data represented or stored in root node, parent node and child node). The following figure shows the example of hierarchical database model for the university management system. This type of database employs the “parent-child” relationship of storing data.
Advantages • The model allows us easy addition and deletion of new information. Disadvantages • It requires data to be repetitively stored in many different entities.
2. Network databases This is looks like a Hierarchical database model due to which many time it is called as modified version of Hierarchical database. Network database model organised data more like a graph and can have more than one parent node. The network model is a database model conceived as a flexible way of representing objects and their relationships. Advantage • The network model is conceptually simple and easy to design. Disadvantage: • All the records are maintained using pointers and hence the whole database structure becomes very complex. 3. Relational Database A relational database is developed by E. F. Codd in 1970. The various software systems used to maintain relational databases are known as a relational database management system (RDBMS). In this model, data is organised in rows and column structure i.e., two-dimensional tables and the relationship is maintained by storing a common field. It consists of three major components. In relational model, three key terms are heavily used such as relations, attributes, and domains. A relation nothing but is a table with rows and columns. The named columns of the relation are called as attributes, and finally the domain is nothing but the set of values the attributes can take. The following figure gives us the overview of rational database model. Terminology used in Relational Model • Tuple: Each row in a table is known as tuple. Keys of a relation- • Primary key- it is the key that uniquely identifies a table. It doesn’t have null values. Some of the example of relational database are as follows. Oracle: Oracle Database is commonly referred to as Oracle RDBMS or simply as Oracle. It is a multi-model database management system produced and marketed by Oracle Corporation. MySQL: MySQL is an open-source relational database management system (RDBMS) based on Structured Query Language (SQL). MySQL runs on virtually all platforms, including Linux, UNIX, and Windows. Microsoft SQL Server: Microsoft SQL Server is an RDBMS that supports a wide variety of transaction processing, business intelligence, and analytics applications in corporate IT environments. PostgreSQL: PostgreSQL, often simply Postgres, is an object-relational database management system (ORDBMS) with an emphasis on extensibility and standards compliance. DB2: DB2 is an RDBMS designed to store, analyze, and retrieve data efficiently. The following tables shows the sample relational database model for the bank environment where the data associated with the bank is stored in the form two dimensional tables. Advantage • Relational model is one of the most popular used database model. Disadvantages • Mapping of objects in relational database is very difficult. 4. Object-oriented databases An object database is a system in which information is represented in the form of objects as used in object-oriented programming. Object oriented databases are different from relational databases which are table-oriented. The object-oriented data model is based on the object-oriented- programming language concept, which is now in wide use. Inheritance, polymorphism, overloading. object-identity, encapsulation and information hiding with methods to provide an interface to objects, are among the key concepts of object-oriented programming that have found applications in data modelling. The object-oriented data model also supports a rich type system, including structured and collection types. The following figure shows the difference between relation and object-oriented database model. The following figure shows an example of object-oriented model. Advantages • Object database can handle different types of data while relational data base handles a single data. Unlike traditional databases like
hierarchical, network or relational, the object-oriented databases can handle the different types of data, for example, pictures, voice video, including text, numbers and so on.
Disadvantages • There is no universally defined data model for an OODBMS, and most models lack a theoretical foundation. What is the type of logical database model that treats data as if they were stored in twoRelational Database
The various software systems used to maintain relational databases are known as a relational database management system (RDBMS). In this model, data is organised in rows and column structure i.e., two-dimensional tables and the relationship is maintained by storing a common field.
Which of the following database types would be best suited for storing multimedia?Which of the following database types would be best suited for storing multimedia? NoSQL DBMS.
What is the logical view of a database?A logical view of data is a representation of data that resides in an enterprise. A logical view of data includes a logical data model, logical data objects, and logical data object mappings.
What is the proper term for activities that detect and correct data in a database that are incorrect incomplete improperly formatted or redundant?Data cleansing, also known as data scrubbing, consists of activities for detecting and correcting data in a database or file that are incorrect, incomplete, improperly formatted, or redundant.
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