Terminal table
A database is a collection of tables that is used for some purpose (typically an application of some sort). A database model is a description of that database, and describes how the tables relate to each other. Typically, a model is designed first, then the actual database is implemented using the model as a blueprint.
network model is a collection data in which records are physically linked through linked lists .A DBMS is said to be a Network DBMS if the relationships among data in the database are of type many-to-many. The relationships among many-to-many appears in the form of a network. Thus the structure of a network database is extremely complicated because of these many-to-many relationships in which one record can be used as a key of the entire database. A network database is structured in the form of a graph that is also a data structure .
In software engineering, an Entity - Relationship model(ER model for short) is an abstract and conceptual representation of data. Entity-relationship modeling is a database modeling method, used to produce a type of conceptual schema or semantic data model of a system, often a relational database, and its requirements in a top-down fashion. Diagrams created by this process are called entity-relationship diagrams or ER diagrams.learn more www.ngprakasam.hpage.com
ADVANTAGESProvide very efficient "High-speed" retrievalSimplicityThe network model is conceptually simple and easy to design.Ability to handle more relationship typesThe network model can handle the one-to-many and many-to-many relationships.Ease of data accessIn the network database terminology, a relationship is a set. Each set comprises of two types of records.- an owner record and a member record, In a network model an application can access an owner record and all the member records within a set.Data IntegrityIn a network model, no member can exist without an owner. A user must therefore first define the owner record and then the member record. This ensures the integrity.Data IndependenceThe network model draws a clear line of demarcation between programs and the complex physical storage details. The application programs work independently of the data. Any changes made in the data characteristics do not affect the application program.DISADVANTAGESSystem complexityIn a network model, data are accessed one record at a time. This males it essential for the database designers, administrators, and programmers to be familiar with the internal data structures to gain access to the data. Therefore, a user friendly database management system cannot be created using the network modelLack of Structural independence.Making structural modifications to the database is very difficult in the network database model as the data access method is navigational. Any changes made to the database structure require the application programs to be modified before they can access data. Though the network model achieves data independence, it still fails to achieve structural independence.Read more: The_advantages_and_disadvantages_of_database_network_model
Entity-relationship model advantages and disadvantages AdvantagesDisadvantagesConceptual simplicityVisual representationEffective communicationIntegration with the relational database modelLimited constraint representationLimited relationship representationNo representation of data manipulationLoss of information
combination of interpreter and compiler.
Relational Database Model
it is the theoretical foundation of a database which fundamentally
Relational model of database is a good way to represent the database. Also network data model and hierarchical model can be used depending on the requirements.
A database is a collection of tables that is used for some purpose (typically an application of some sort). A database model is a description of that database, and describes how the tables relate to each other. Typically, a model is designed first, then the actual database is implemented using the model as a blueprint.
The logic structure is independent of any kind of data model,in the practical application, the general database used by theenvironment has given (such as SQL Server or Oracel or MySQL. Due to the current use of the database basically is relational database, so the first thing to the E-R diagram into relation model, and then according to the characteristics andlimitations of specific DBMS conversion for the specificsupport of DBMS data model, the final optimization
what is the architecture of database network
simplified standard model of database
One of the advantages of a relational database model is that the broken keys and records and the data complexity are usually simplified. The disadvantage of the relational database model is that it requires sophisticated processing power which is very costly.
A hierarchical model is a database model which represents the database in a tree diagram. It thus helps the user to work with(i.e., use, modify, extract etc.) the database without even bothering about the complicated algorithms or flow chart used by the system to deal with the database.
Answering "List the advantage and disadvantage of object oriented database model?" Answering "List the advantage and disadvantage of object oriented database model?"
the ---- of a database presents the views that the end user have