The structure of database is more like graph rather than tree structure. So network, database model was emerged to arranged non-hierarchical database. Suppose, if an employee relates to two departments, then the hierarchical database model cannot able to arrange records in proper place. Network database model: it replaced hierarchical network database model due to some limitations on the model. The relationship between the records is called parent child relationship in which any child record relates to only a single parent type record. All records are arranged in database as tree like structure. In this model data is represented in the form of records. HierarchicDal database model: this is one of the oldest type of database models. In some cases, top-down design can lead to unsatisfactory results because the analyst and end-users can miss something that is important and is necessary for the system. The top-down method also can have shortcomings. Using the top-down method requires that the analyst has a detailed understanding of the system. The analyst will then work with the users to determine what data should be kept in the database. Basically, you start with a general idea of what is needed for the system and then ask the end-users what data they need to store. The top-down method starts from the general and moves to the specific. Later, the programming team looks at the requirements of each of those database components and the process is repeated. The technique for designing a database using top-down methods is to write a main database parts that names all the major storage and retrievals it will need. It allows accessing the files, updating the records and retrieving data as requested. The database system which stores and displays data in tabular format of rows and columns, like spreadsheet, is known as Relational Database Management System.ĭatabase: it is a collection of related information about a subject organized in a useful manner that provides a base or foundation for procedure, such as retrieving information, drawing conclusion and make decision.ĭBMS: A DBMS is a set of programs that manages the database files. Relational Database Management System (RDBMS)

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