The advantages and disadvantages of database network model? ADVANTAGES
Provide very efficient "High-speed" retrieval Simplicity
The network model is conceptually simple and easy to design.
Ability to handle more relationship types
The network model can handle the one-to-many and many-to-many relationships.
Ease of data access
In 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 Integrity
In 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 Independence
The 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. DISADVANTAGES
System complexity
In 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 model
Lack 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.
What is Hierarchical Model,Advantages and Disadvantages of Hierarchical Model HIERARCHICAL MODEL Hierarchical database model is one of the oldest database models, dating from late 1950s. One of the first hierarchical database information management systems (IMS) was developed jointly by North American Rockwell Company and IBM. This model is like a structure of a tree with the records forming the nodes and fields forming the branches of the tree.
Hierarchical Model Advantages and disadvantages of Hierarchical model 1.Simplicity: Since the database is based on the hierarchical structure, the relationship between the various layers is logically simple. 2.Data Security :Hierarchical model was the first database model that offered the data security that is provided by the dbms. 3.Data Integrity: Since it is based on the parent child relationship, there is always a link between the parent segment and the child segment under it. 4.Efficiency: It is very efficient because when the database contains a large number of 1:N relationship and when the user require large number of transaction. Disadvantages of Hierarchical model: 1. Implementation complexity: Although it is simple and easy to design, it is quite complex to implement. 2.Database Management Problem: If you make any changes in the database structure, then you need to make changes in the entire application program that access the database.
3.Lack of Structural Independence: there is lack of structural independence because when we change the structure then it becomes compulsory to change the application too. 4.Operational Anomalies: Hierarchical model suffers from the insert, delete and update anomalies, also retrieval operation is difficult.
What is Relational Model, Advantages and Disadvantages of Relational Model
Relational Model: Relational model stores data in the form of tables. The relational model consists of three major components 1. The set of relations and set of domains that defines the way data can be represented ( data structure). 2. Integrity rules that define the procedures to protect the data (data integrity). 3. The operation that can be operate on the data (data manipulation).
Relational Model A relational model database is defined as a database that allows you to group its data items into one or more independent tables that can be related to one another by using fields common to each related table. Basic terminology used in relational model
Attributes Emp_code Name Year 12 Saurav 1984 Tuples 13 Chirag 1985 14 Jagdeep 1983 Tuples of a Relation: Each row in data is actually a tuple. Cardinality of a Relation: The number of tuples in a relation determines its cardinality. Degree of relation: Each column in the tuple is called attribute. The umber of attributes in tuple determines its degree. Domain: a domain. Specifies the type of data represented by the attribute or a domain is all kind of values that an attribute can validly contain. Domains are often confused by data types; data type is physical concept while domain is logical. Number is data type and age is domain. Keys of a Relation: it is a set of one or more columns whose combined values are unique. Some different types of keys are: Primary key: primary key is an attribute or set of attributes of relation which posses the properties of uniqueness. Foreign Key: foreign Key is the attribute of a table, which refers to the primary key of some other table. Foreign key permits only those values, which appear in the primary key of the table to which it refers.
Advantages of Relational Model: Conceptual Simplicity: We have seen that both the hierarchical and network models are conceptually simple, but relational model is simpler than both of those two. Structural Independence: In the Relational model, changes in the structure do not affect the data access. Design Implementation: the relational model achieves both data independence and structural independence. Ad hoc query capability: the presence of very powerful, flexible and easy to use capability is one of the main reason for the immense popularity of the relational database model. Disadvantages of Relational Model: Hardware overheads: relational database systems hide the implementation complexities and the physical data storage details from the user. For doing this, the relational database system need more powerful hardware computers and data storage devices. Ease of design can lead to bad design: the relational database is easy to design and use. The user needs not to know the complexities of the data storage. This ease of design and use can lead to the development and implementation of the very poorly designed database management system.
What is the difference between an object-oriented and object-relational database? "In an object oriented database, information is represented in the form of objects as used in ObjectOriented Programming. When database capabilities are combined with object programming language capabilities, the result is an object database management system (ODBMS). An ODBMS makes database objects appear as programming language objects in one or more object programming languages. An ODBMS extends the programming language with transparently persistent data, concurrency control, data recovery, associative queries, and other c apabilities. Some object-oriented databases are designed to work well with object-oriented programming languages such as Python, Java, C#, Visual Basic .NET, C++ and Smalltalk. Others have their o wn programming languages. ODBMSs use exactly the same model as object-oriented programming languages. Object databases are generally re commended when there is a business need for high performance processing on complex data." -wiki "An object-relational database (ORD) or object-relational database management system (ORDBMS) is a relational database management system that allows developers to integrate the database with their own custom data types and methods. The term object-relational database is sometimes used to describe external software products running over tr aditional DBMSs to provide similar features; these systems are more correctly referred to as object-relational mapping systems. Whereas RDBMS or SQL-DBMS products focused on the efficient management of data drawn from a limited set of data types (defined by the relevant language standards), an object-relational DBMS allows software developers to integrate t heir own types and the methods that apply to them into the DBMS. The goal of ORDBMS technology is to allow developers to raise the level of abstraction at which they view the problem domain."
