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Traditional file based system is basically a file based system, in which we manually or through computer handle the database such as updating, insertion ,deletion adding new files to database etc.
We either manually or through computer handle databse. In other words files are upated, deleted or inserted in a databse.This traditional file based sysem is in use for a verylong time.
There are a number of advantages of traditional file system that includes,
External storage is not necessary.
A person with limited technical knowkedge can handle databse.
Comparatively processing speed is good than DBMS
Advantage of Traditional File system
No need of external storage
No need of highly technical person to handle the database.
Processing speed is high as compare to DBMS
Disadvantages of Traditional File system
Provide less security.
Redundancy is more
High complexity in updating of database
Database Management System
A special data processing system, or part of a data processing system, which aids in the storage, manipulation, reporting, management, and control of data. Abbreviated DBMS.
Reduced data redundancy
Reduced updating errors and increased consistency
Greater data integrity and independence from applications programs
Improved data access to users through use of host and query languages
Improved data security
Reduced data entry, storage, and retrieval costs
Facilitated development of new applications program
Database systems are complex, difficult, and time-consuming to design
Substantial hardware and software start-up costs
Damage to database affects virtually all applications programs
Extensive conversion costs in moving form a file-based system to a database system
Initial training required for all programmers and users
Data model explicitly determines the meaning of data, which in this case is known as structured data (as opposed to unstructured data for example an image binary file or a natural language text, where the meaning has to be leeboard).Typical applications of data model include database models, design of information system, and enabling exchange of data .usually data models are specified in a data modeling language
A data model can be sometimes referred to as a data structure especially in the context of programming languages data models are often complemented by function models especially in the context of enterprise models
Hierarchical data model
Network data model
Relational data model
Object oriented data model
Post Relational data model
Deductive data model
Hierarchical data model
A hierarchical data model is a data model in which the data is organized into a tree-like structure. The structure allows repeating information using parent/child relationships: each parent can have many children but each child only has one parent. All attributes of a specific record are listed under an entity type.
In a database, an entity type is the equivalent of a table; each individual record is represented as a row and an attribute as a column. Entity types are related to each other using 1:ÂÂ N mapping, also known as one-to-many relationships.
The hierarchical data model organizes data in a tree structure. There is a hierarchy of parent and child data segments. This structure implies that a record can have repeating information, generally in the child data segments. Data in a series of records, which have a set of field values attached to it. It collects all the instances of a specific record together as a record type. These record types are the equivalent of tables in the relational model, and with the individual records being the equivalent of rows. To create links between these record types, the hierarchical model uses Parent Child Relationships. These are a
1: N mapping between record types. This is done by using trees, like set theory used in the relational model, "borrowed" from maths. For example, an organization might store information about an employee, such as name, employee number, department, salary. The organization might also store information about an employee's children, such as name and date of birth. The employee and children data forms a hierarchy, where the employee data represents the parent segment and the children data represents the child segment. If an employee has three children, then there would be three child segments associated with one employee segment. In a hierarchical database the parent-child relationship is one to many. This restricts a child segment to having only one parent segment. Hierarchical DBMSs were popular from the late 1960s, with the introduction of IBM's Information Management System (IMS) DBMS, through the 1970s
The hierarchical data model has the following features:
Each hierarchical tree can have only one root record type and this record type does not have a parent record type
The root carts have any number of child record types and each of which can itself be a root of a hierarchical sub tree
Each child record type can have only one parent record type; thus a M: N relationship cannot be directly expressed between two record types
Data in a parent record applies to all its children records
Network data model
The network model is a database model conceived as a flexible way of representing objects and their relationships. Its distinguishing feature is that the schema, viewed as a graph in which object types are nodes and relationship types are arcs, is not restricted to being a hierarchy or lattice
The network data model was formalized in the late 1960s by the Database Task Group of the Conference on Data System Language (DBTG/CODASYL). Their first report which has been revised a number of times, contained detailed specifications for the network data model (a model conforming to these specifications is also known as the DBTG data model).
The popularity of the network data model coincided with the popularity of the hierarchical data model. Some data were more naturally modeled with more than one parent per child. So, the network model permitted the modeling of many-to-many relationships in data. In 1971, the Conference on Data Systems Languages (CODASYL) formally defined the network model. The basic data modeling construct in the network model is the set construct. A set consists of an owner record type, a set name, and a member record type. A member record type can have that role in more than one set, hence the multivalent concept is supported. An owner record type can also be a member or owner in another set. The data model is a simple network, and link and intersection record types (called junction records by IDMS) may exist, as well as sets between them
Implementation of the Network Data Model
The record is a basic unit to represent data in the DBTG network database model. The implementation of the one-to-many relationships of a set is represented by linking the members of a given occurrence of a set to the owner record occurrence. The actual method of linking the member record occurrence to the owner is immaterial to the user of the database; however, for our discussion, we can assume that the set is implemented using a linked list. The list starts at the owner record occurrence and links all the member record occurrences with the pointer in the last member record occurrence leading back to the owner record.
Rows and columns can be logically manipulated by Boolean operators ("and," "or," "not") to determine records that satisfy complex associations (e.g., any record that has both parent S and parent T).
A bit map can be manipulated equally as well in either a row or column access (all the row records for a common column or all the column records for a common row) and can be easily extended for n-ray relationships).
Relational data model
(RDBMS - relational database management system) A database based on the relational model developed by E.F. Cod. A relational database allows the definition of data structures, storage and retrieval operations and integrity constraints. In such a database the data and relations between them are organized in tables. A table is a collection of records and each record in a table contains the same fields.
Properties of Relational Tables:
Values Are Atomic
Each Row is Unique
Column Values Are of the Same Kind
The Sequence of Columns is Insignificant
The Sequence of Rows is Insignificant
Certain fields may be designated as keys, which mean that searches for specific values of that field will use indexing to speed them up. Where fields in two different tables take values from the same set, a join operation can be performed to select related records in the two tables by matching values in those fields. Often, but not always, the fields will have the same name in both tables. For example, an "orders" table might contain (customer-ID, product-code) pairs and a "products" table might contain (product-code, price) pairs so to calculate a given customer's bill you would sum the prices of all products ordered by that customer by joining on the product-code fields of the two tables. This can be extended to joining multiple tables on multiple fields. Because these relationships are only specified at retrieval time, relational databases are classed as dynamic database management system. The RELATIONAL database model is based on the Relational Algebra.
The differences that arise in the relational approach is in setting up relationships between different tables. This actually makes use of certain mathematical operations on the relation such as projection, union, joins, etc. These operations from relational algebra and relational calculus are discussion in some more details in the second Block of this course. Similarly in order to achieve the organization of the data in terms of tables in a satisfactory manner, a technique called normalization is used.
Example of a Relational Model
Let us see important features of a RDBMS through some examples as shown in before table a relation has the following properties:
Each column contains values about the same attribute, and each table cell value must be simple (a single value).
Each column has a distinct name (attribute name), and the order of columns is immaterial.
Each row is distinct; that is, one row cannot duplicate another row for selected key attribute columns.
Components of data base system
The hardware are the parts of computer itself including the central processing Unit (CPU) and related microchips and micro-circuitry, keyboards, monitors, case, and drives (Floppy, hard, CD, DVD, optical, tape, etc..). Other extra parts called peripheral components or devices include mouse, printers, modems, scanners, digital, cameras and cards (sound, colour, video) etcââ‚¬Â¦ together they are often referred to as a personal computers or Pcââ‚¬â„¢s
The software is the information that the computer uses to get the job done. Software needs to be accessed before it can be used. There are many terms used for process of accessing software including running, executing, starting up, opening, and others.
System analyst and Software programmer
Importance of DBMS in commercial & non commercials:
Database management system (DBMS) is computer software that manages databases. DBMS may use any of a variety of database models, such as the network model or relational model. In large systems, a DBMS allows users and other software to store and retrieve data in a structured way.
A DBMS is a set of software programs that controls the organization, storage, management, and retrieval of data in a database. DBMS are categorized according to their data structures or types. It is a set of prewritten programs that are used to store, update and retrieve a Database. The DBMS accepts requests for data from the application program and instructs the operating system to transfer the appropriate data. When a DBMS is used, information systems can be changed much more easily as the organization's information requirements change. New categories of data can be added to the database without disruption to the existing system.
Organizations may use one kind of DBMS for daily transaction processing and then move the detail onto another computer that uses another DBMS better suited for random inquiries and analysis. Overall systems design decisions are performed by data administrators and systems analysts. Detailed database design is performed by database administrators.
Database servers are specially designed computers that hold the actual databases and run only the DBMS and related software. Database servers are usually multiprocessor computers, with RAID disk arrays used for stable storage. Connected to one or more servers via a high-speed channel, hardware database accelerators are also used in large volume transaction processing environments. DBMSs are found at the heart of most database applications. Sometimes DBMSs are built around a private multitasking kernel with built-in networking support although nowadays these functions are left to the operating system.
Database management system is the system of computer software that is aimed to provide a managing tool for maintaining the data, through various data models. If you look over the large companies or even the smaller ones, can you believe that all of them are maintaining the manual registers for the collection of data? Obviously not! The invention of computer and the software has made it easy to manage the data of all types in the database management system
and then having a direct access to data more quickly and easily than the manual system. For example, if you go to your doctor for a routinely check up, he will have a record of the last time you visited him. This shows that for each patient he will have the same record and this is what the database management system is supposed to do.